Faculty Profiles - HONDA, Yoshio

Polarization properties in InGaN/GaN multiple quantum well on semipolar(1-101)GaN/Si

KUSHIMOTO Maki, TANIKAWA Tomoyuki, HONDA Yoshio, YAMAGUCHI Masahito, AMANO Hiroshi

IEICE technical report. Component parts and materials Vol. 112 ( 33 ) page： 15 - 18 2012.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

We grew high-quality semipolar (1-101) GaN stripes on a Si substrate by selective area growth and regrew InGaN/GaN MQW on these stripes with MOVPE. The PL peak wavelength at 300 K and InGaN well thickness for the obtained samples were 435-590 nm and 2-9 nm, respectively. In PL measurements from the surface, we found that a shorter wavelength and thinner well sample have PL polarization perpendicular to the c axis. On the other hand, as the PL wavelength is longer and/or the well is thicker, the PL polarization shifts from perpendicular to parallel. In the PL measurement from the (11 -22) edge surface of the sample with shorter wavelength, we observed the narrowing of PL spectrum. In addition, the parallel component of PL polarization increased with increase in well thickness. Therefore, we can control the direction of polarization by managing well thickness and indium composition and apply to make a LD structure.

Crystal Growth of Semipolar GaN on Si Substrate(<Special Issue>Breakthrough in Nitride Crystal Growth for Next Generation Devices)

Strain relaxation in thick ($1{\bar {1}}01$) InGaN grown on GaN/Si substrate Reviewed

Tanikawa Tomoyuki, Honda Yoshio, Yamaguchi Masahito, Amano Hiroshi, Sawaki Nobuhiko

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Vol. 249 ( 3 ) page： 468 - 471 2012.3

Impurity incorporation in semipolar (1-1 0 1) GaN grown on an Si substrate Reviewed

Sawaki Nobuhiko, Hagiwara Kiyotaka, Hikosaka Toshiki, Honda Yoshio

SEMICONDUCTOR SCIENCE AND TECHNOLOGY Vol. 27 ( 2 ) 2012.2

Honda Yoshio

Journal of the Japanese Association for Crystal Growth Vol. 38 ( 4 ) page： 241 - 248 2012

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Association for Crystal Growth

(1-101) GaN and (11-22) GaN was grown by MOVPE on etched Si substrate. A characteristic of optical, electrical and impurity was evaluated on each face GaN. We also reported an Indium incorporation and a process of dislocation propagation on the (1-101) GaN in this paper.

DOI： 10.19009/jjacg.38.4_241

Improvement of Light Extraction Efficiency for AlGaN-Based Deep Ultraviolet Light-Emitting Diodes Reviewed

Inazu Tetsuhiko, Fukahori Shinya, Pernot Cyril, Kim Myung Hee, Fujita Takehiko, Nagasawa Yosuke, Hirano Akira, Ippommatsu Masamichi, Iwaya Motoaki, Takeuchi Tetsuya, Kamiyama Satoshi, Yamaguchi Masahito, Honda Yoshio, Amano Hiroshi, Akasaki Isamu

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 50 ( 12 ) 2011.12

AlGaN-Based Deep Ultraviolet Light-Emitting Diodes Fabricated on Patterned Sapphire Substrates Reviewed

Kim Myunghee, Fujita Takehiko, Fukahori Shinya, Inazu Tetsuhiko, Pernot Cyril, Nagasawa Yosuke, Hirano Akira, Ippommatsu Masamichi, Iwaya Motoaki, Takeuchi Tetsuya, Kamiyama Satoshi, Yamaguchi Masahito, Honda Yoshio, Amano Hiroshi, Akasaki Isamu

APPLIED PHYSICS EXPRESS Vol. 4 ( 9 ) 2011.9

Effect of lateral vapor phase diffusion during the selective growth of InGaN/GaN MQW on semipolar and nonpolar GaN stripes Reviewed Open Access

Tanikawa Tomoyuki, Honda Yoshio, Yamaguchi Masahito, Amano Hiroshi

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE Vol. 208 ( 5 ) page： 1175 - 1178 2011.5

Optical properties of (1 (1)over-bar 0 1) semi-polar InGaN/GaN multiple quantum wells grown on patterned silicon substrates Reviewed

Chiu Ching-Hsueh, Lin Da-Wei, Lin Chien-Chung, Li Zhen-Yu, Chen Yi-Chen, Ling Shih-Chun, Kuo Hao-Chung, Lu Tien-Chang, Wang Shing-Chung, Liao Wei-Tsai, Tanikawa Tomoyuki, Honda Yoshio, Yamaguchi Masahito, Sawaki Nobuhiko

JOURNAL OF CRYSTAL GROWTH Vol. 318 ( 1 ) page： 500 - 504 2011.3

Drastic Reduction of Dislocation Density in Semipolar (11(2)over-bar2) GaN Stripe Crystal on Si Substrate by Dual Selective Metal-Organic Vapor Phase Epitaxy Reviewed

Murase Tasuku, Tanikawa Tomoyuki, Honda Yoshio, Yamaguchi Masahito, Amano Hiroshi, Sawaki Nobuhiko

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 50 ( 1 ) 2011.1

Semi-polar GaN LEDs on Si substrate Reviewed

Sawaki Nobuhiko, Honda Yoshio

SCIENCE CHINA-TECHNOLOGICAL SCIENCES Vol. 54 ( 1 ) page： 38 - 41 2011.1

Reduction of Efficiency Droop in Semipolar (1(1)over-bar01) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates Reviewed

Chiu Ching-Hsueh, Lin Da-Wei, Lin Chien-Chung, Li Zhen-Yu, Chang Wei-Ting, Hsu Hung-Wen, Kuo Hao-Chung, Lu Tien-Chang, Wang Shing-Chung, Liao Wei-Tsai, Tanikawa Tomoyuki, Honda Yoshio, Yamaguchi Masahito, Sawaki Nobuhiko

APPLIED PHYSICS EXPRESS Vol. 4 ( 1 ) 2011.1

Raman Spectroscopic Study Of Residual Strain In (1-101) GaN And (0001) GaN Layers Grown On Si Substrate Reviewed

Sugiura Toko, Kim Eun-Hee, Honda Yoshio, Takagi Hiroyuki, Tsukamoto Takehiko, Andoh Hiroya, Yamaguchi Masahito, Sawaki Nobuhiko

PHYSICS OF SEMICONDUCTORS: 30TH INTERNATIONAL CONFERENCE ON THE PHYSICS OF SEMICONDUCTORS Vol. 1399 2011

Achieving high-growth-rate in GaN homoepitaxy using high-density nitrogen radical source Reviewed

Kawai Yohjiro, Chen Shang, Honda Yoshio, Yamaguchi Masahito, Amano Hiroshi, Kondo Hiroki, Hiramatsu Mineo, Kano Hiroyuki, Yamakawa Koji, Den Shoji, Hori Masaru

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 8, NO 7-8 Vol. 8 ( 7-8 ) 2011

Raman spectroscopic study of residual strain and stress in GaN layer grown on Si substrates

Touko SUGIURA, Yoshio HONDA, Akihiro OKAMOTO, Hiroyuki TAKAGI, Takehiko TSUKAMOTO, Hiroya ANDOH

Journal of National Institute of Technology, Toyota College Vol. 42 ( 0 ) page： 19 - 22 2010

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：National Institute of Technology, Toyota College

We have studied the residual strain and stress in semi-polar (1-101)GaN and conventional (0001)GaN grown on Si by means of Raman spectroscopy. By adopting the stress coefficients reported in the references, the residual strain of samples were deduced from the frequency shifts of the phonon modes in Raman spectra. As the results, it was found that the strain tensor of (1-101) GaN/Si was smaller than that of the (0001)GaN/Si in good agreement with the results obtained from the X-ray diffraction measurements.

DOI： 10.20692/toyotakosenkiyo.kj00005889042

Influence of a SiO2 Mask on the Growth of Semi-Polar (11-22) GaN on Patterned Si (311) Substrates Reviewed

Yang Min, Ahn Hyung Soo, Tanikawa Tomoyuki, Honda Yoshio, Yamaguchi Masahito, Sawaki Nobuhiko

JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. 54 ( 6 ) page： 2363 - 2366 2009.6

Growth and properties of semi-polar GaN on a patterned silicon substrate Reviewed

Sawaki Nobuhiko, Hikosaka Toshiki, Koide Norikatsu, Tanaka Shigeyasu, Honda Yoshio, Yamaguchi Masahito

JOURNAL OF CRYSTAL GROWTH Vol. 311 ( 10 ) page： 2867 - 2874 2009.5

Maskless selective growth of semi-polar (11(2)over-bar2) GaN on Si (311) substrate by metal organic vapor phase epitaxy Reviewed

Yang Min, Ahn Hyung Soo, Tanikawa Tomoyuki, Honda Yoshio, Yamaguchi Masahito, Sawaki Nobuhiko

JOURNAL OF CRYSTAL GROWTH Vol. 311 ( 10 ) page： 2914 - 2918 2009.5

Scattering times in the two-dimensional electron gas of AlxGa1-xN/AlN/GaN heterostructures Reviewed

Han Xiuxun, Honda Yoshio, Narita Tetsuo, Yamaguchi Masahito, Sawaki Nobuhiko, Tanaka Tooru, Guo Qixin, Nishio Mitsushiro

JOURNAL OF PHYSICS D-APPLIED PHYSICS Vol. 42 ( 4 ) 2009.2

Electron-beam-induced-current investigation of GaN/AlGaN/Si heterostructures using scanning transmission electron microscopy Reviewed

TANAKA Shigeyasu, AOYAMA Kentaro, ICHIHASHI Mikio, ARAI Shigeo, HONDA Yoshio, SAWAKI Nobuhiko

Journal of electron microscopy Vol. 56 ( 4 ) page： 141 - 144 2007.8

Electron-beam-induced-current investigation of GaN/AlGaN/Si heterostructures using scanning transmission electron microscopy Reviewed

Tanaka Shigeyasu, Aoyama Kentaro, Ichihashi Mikio, Arai Shigeo, Honda Yoshio, Sawaki Nobuhiko

JOURNAL OF ELECTRON MICROSCOPY Vol. 56 ( 4 ) page： 141 - 144 2007.8

Application of electron holography to the determination of contact potential difference in an AlGaN/AlN/Si heterostructure Reviewed

TANAKA Shigeyasu, NAITO Akiyuki, HONDA Yoshio, SAWAKI Nobuhiko, ICHIHASHI Mikio

Journal of electron microscopy Vol. 56 ( 2 ) page： 37 - 42 2007.4

Application of electron holography to the determination of contact potential difference in an AIGaN/AIN/Si heterostructure Reviewed

Tanaka Shigeyasu, Naito Akiyuki, Honda Yoshio, Sawaki Nobuhiko, Ichihashi Mikio

JOURNAL OF ELECTRON MICROSCOPY Vol. 56 ( 2 ) page： 37 - 42 2007.4

Mg doping in (1(1)over-bar01)GaN grown on a 7 degrees off-axis (001)Si substrate by selective MOVPE Reviewed

Hikosaka Toshiki, Koide Norikatsu, Honda Yoshio, Yamaguchi Masahito, Sawaki Nobuhiko

JOURNAL OF CRYSTAL GROWTH Vol. 298 page： 207 - 210 2007.1

Carbon incorporation on (1101) facet of AlGaN in metal organic vapor phase epitaxy Reviewed

Koide Norikatsu, Hikosaka Toshiki, Honda Yoshio, Yamaguchi Masahito, Sawaki Nobuhiko

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS Vol. 45 ( 10A ) page： 7655 - 7660 2006.10

The surface diffusion of Ga on an AlGaN/GaN stripe structure in the selective MOVPE Reviewed

Narita Tetsuo, Honda Yoshio, Yamaguchi Masahito, Sawaki Nobuhiko

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Vol. 243 ( 7 ) page： 1665 - 1668 2006.6

Series resistance in n-GaN/AIN/n-Si heterojunction structure Reviewed

Kondo Hiroyuki, Koide Norikatsu, Honda Yoshio, Yamaguchi Masahito, Sawaki Nobuhiko

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS Vol. 45 ( 5A ) page： 4015 - 4017 2006.5

The effect of Si and C doping to the (1-101)GaN grown on a 7-degree-off oriented (001)Si substrate

HIKOSAKA Toshiki, KOIDE Norikatsu, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

Technical report of IEICE. SDM Vol. 105 ( 94 ) page： 69 - 74 2005.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Using a selective MOVPE method, (1-101)GaN was grown on a 7-degree off-axis (001)Si substrate. The top (1-101) surface of the sample was terminated with N, which is contrast to that the (0001) face is terminated with Ga. The doping of Si and C was attempted to control the type of conduction. A nominally undoped GaN/AlN heterostructure showed p-type conduction. The doping of Si changed the type of conduction from p-type to n-type. On the other hand, the hole concentration increased with the C doping level. These results proves that Si acts as a donor and C acts as an acceptor in (1-101)GaN. We might conclude that the p-type conduction is due to the incorporation of C on the top surface of the N face of the GaN.

Selective Growth of GaN/AlGaN Microstructures by Metalorganic Vapor Phase Epitaxy. Reviewed

[Congenital middle ear cholesteatoma: experience in 48 cases].

Kojima H, Miyazaki H, Tanaka Y, Shiwa M, Honda Y, Moriyama H

Nihon Jibiinkoka Gakkai kaiho Vol. 106 ( 9 ) page： 856 - 65 2003.9

Kato Tomonobu, Honda Yoshio, Kawaguchi Yasutoshi, Yamaguchi Masahito, Sawaki Nobuhiko

Japanese Journal of Applied Physics Vol. 40 ( 3B ) page： 1896 - 1898 2001

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Applied Physics

A GaN/AlGaN double heterostructure was fabricated on the (1101) facets of a GaN triangular structure prepared by selective area growth by metalorganic vapor phase epitaxy. The photoluminescence (PL) and cathode luminescence (CL) spectra were investigated to characterize the structure. It was found that the PL peak wavelength due to the GaN quantum well is dependent on the well thickness. However, the Al composition of the AlGaN layer is dependent on the position on the (1101) facet. The anomalous gradient of the composition is attributed to the difference in the diffusion coefficients of Al and Ga on the surface.

DOI： 10.1143/jjap.40.1896

Selective Area Growth of GaN on Si Substrate Using SiO2 Mask by Metalorganic Vapor Phase Epitaxy. Reviewed

Kawaguchi Yasutoshi, Honda Yoshio, Matsushima Hidetada, Yamaguchi Masahito, Hiramatsu Kazumasa, Sawaki Nobuhiko

Japanese Journal of Applied Physics Vol. 37 ( 8B ) page： L966 - L969 1998

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Applied Physics

Selective area growth (SAG) of GaN on (111) Si substrate was studied using AlGaN as an intermediate layer. A hexagonal dot with a (0001) plane on the top and of a 5 µm or a submicron size was obtained using a patterned dot structure of silicon dioxide (SiO2) mask. The facet structure revealed that the <11\=20> axis of hexagonal GaN is parallel to the <110> axis of the Si substrate. The cathodoluminescence (CL) spectrum at 133 K exhibited a strong near-band-edge emission band for the submicron dots, which suggests excellent crystallinity. Epitaxial lateral overgrowth (ELO) of GaN on the Si substrate is demonstrated.

DOI： 10.1143/jjap.37.l966

Sn-doped n-type GaN freestanding layer: Thermodynamic study and fabrication by halide vapor phase epitaxy Open Access

Kazuki Ohnishi, Kansuke Hamasaki, Shugo Nitta, Naoki Fujimoto, Hirotaka Watanabe, Yoshio Honda, Hiroshi Amano

Journal of Crystal Growth Vol. 648 2024.12

Language：English Publishing type：Research paper (scientific journal)

Results of a thermodynamic study of Sn doping and fabrication of a Sn-doped GaN freestanding layer with high structural quality by halide vapor phase epitaxy (HVPE) are described in this paper. Thermodynamic analysis revealed that SnCl2 and/or SnCl act as Sn precursors through the reaction between Sn metal and HCl gas. The equilibrium partial pressures of SnCl2 and SnCl increase with the input HCl partial pressure. To generate Sn precursors effectively, it is desirable that the reaction between Sn metal and HCl gas occurs in the inert gas ambient. On the basis of results of the thermodynamic study, the Sn-doped GaN freestanding layer with a Sn concentration of 5.7 × 1019 cm−3 is fabricated by removing the GaN seed substrate after HVPE growth. The Sn-doped GaN freestanding layer has high crystal quality, and the lattice constants along the c- and a-axes of the Sn-doped GaN freestanding layer are larger than those of the GaN seed substrate because of the high electron density and the size effect of Sn atoms.

DOI： 10.1016/j.jcrysgro.2024.127923

Impacts of vacancy complexes on the room-temperature photoluminescence lifetimes of state-of-the-art GaN substrates, epitaxial layers, and Mg-implanted layers

Shigefusa F. Chichibu, Kohei Shima, Akira Uedono, Shoji Ishibashi, Hiroko Iguchi, Tetsuo Narita, Keita Kataoka, Ryo Tanaka, Shinya Takashima, Katsunori Ueno, Masaharu Edo, Hirotaka Watanabe, Atsushi Tanaka, Yoshio Honda, Jun Suda, Hiroshi Amano, Tetsu Kachi, Toshihide Nabatame, Yoshihiro Irokawa, Yasuo Koide

Journal of Applied Physics Vol. 135 ( 18 ) 2024.5

Language：English Publishing type：Research paper (scientific journal) Publisher：AIP Publishing

For rooting the development of GaN-based optoelectronic devices, understanding the roles of midgap recombination centers (MGRCs), namely, nonradiative recombination centers and deep-state radiative recombination centers, on the carrier recombination dynamics is an essential task. By using the combination of time-resolved photoluminescence and positron annihilation spectroscopy (PAS) measurements, the origins of major MGRCs in the state-of-the-art GaN epilayers, bulk crystals, and Mg-implanted layers were identified, and their concentrations were quantified for deriving the capture coefficients of minority carriers. In this article, potential standardization of the room-temperature photoluminescence lifetime for the near-band-edge emission (τPLRT) as the concentration of major MGRCs well below the detection limit of PAS is proposed. For n-GaN substrates and epilayers grown from the vapor phase, τPLRT was limited by the concentration of carbon on N sites or divacancies comprising a Ga vacancy (VGa) and a N vacancy (VN), [VGaVN], when carbon concentration was higher or lower, respectively, than approximately 1016 cm−3. Here, carbon and VGaVN act as major deep-state radiative and nonradiative recombination centers, respectively, while major MGRCs in bulk GaN crystals were identified as VGa(VN)3 vacancy clusters in Na-flux GaN and VGa or VGaVN buried by a hydrogen and/or VGa decorated with oxygen on N sites, VGa(ON)3–4, in ammonothermal GaN. The values of τPLRT in n-GaN samples are compared with those of p-GaN, in which τPLRT was limited by the concentration of VGa(VN)2 in Mg-doped epilayers and by the concentrations of VGaVN and (VGaVN)3 in Mg-implanted GaN right after the implantation and after appropriate activation annealing, respectively.

DOI： 10.1063/5.0201931

Sn-doped n-type GaN layer with high electron density of 1020 cm−3 grown by halide vapor phase epitaxy

Kansuke Hamasaki, Kazuki Ohnishi, Shugo Nitta, Naoki Fujimoto, Hirotaka Watanabe, Yoshio Honda, Hiroshi Amano

Journal of Crystal Growth Vol. 628 page： 127529 - 127529 2024.2

Impacts of off-angle and off-direction on surface morphology of GaN grown by metalorganic vapor phase epitaxy on (0001) GaN substrate

Hirotaka Watanabe, Shugo Nitta, Yuto Ando, Kazuki Ohnishi, Yoshio Honda, Hiroshi Amano

Journal of Crystal Growth Vol. 628 page： 127552 - 127552 2024.2

Optical activation of praseodymium ions implanted in gallium nitride after ultra-high pressure annealing

Shin Ito, Shin ichiro Sato, Michał S. Boćkowski, Manato Deki, Hirotaka Watanabe, Shugo Nitta, Yoshio Honda, Hiroshi Amano, Ken ichi Yoshida, Hideaki Minagawa, Naoto Hagura

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms Vol. 547 2024.2

Language：English Publishing type：Research paper (scientific journal)

Lanthanide (Ln)-implanted gallium nitride (GaN) semiconductors have a variety of potential applications as light-emitting devices and quantum light sources, but their optical properties are not well understood. In this study, we investigate the room temperature optical properties of praseodymium (Pr) ion implanted single-crystal GaN and their changes upon ultrahigh pressure annealing (UHPA) up to 1480 °C. Photoluminescence (PL) spectra, luminescence transition lifetime, and excitation cross section of the implanted Pr ions are analyzed. In addition, the recovery of implantation-induced damage and the thermal diffusion of implanted Pr ions by UHPA are investigated by X-ray diffraction, Raman spectroscopy, and secondary ion mass spectrometry. The results show that the implantation damage is recovered by annealing at temperatures above 1200 °C, but Pr ions thermally diffuse to the surface as the annealing temperature increases. The annealing temperature at which a maximum PL intensity is obtained increases with increasing the implantation dose. However, the PL intensity decreases in all cases after annealing at 1480 °C, indicating that a quenching factor is dominant in this temperature range.

DOI： 10.1016/j.nimb.2023.165181

Investigation of Electrical Properties of N‐Polar AlGaN/AlN Heterostructure Field Effect Transistors

Daisuke Inahara, Shunsuke Matsuda, Wataru Matsumura, Ryo Okuno, Koki Hanasaku, Taketo Kowaki, Minagi Miyamoto, Yongzhao Yao, Yukari Ishikawa, Atsushi Tanaka, Yoshio Honda, Shugo Nitta, Hiroshi Amano, Satoshi Kurai, Narihito Okada, Yoichi Yamada

physica status solidi (a) Vol. 220 ( 16 ) 2023.8

Lateral p-type GaN Schottky barrier diode with annealed Mg ohmic contact layer demonstrating ideal current–voltage characteristic Reviewed

Shun Lu, Manato Deki, Takeru Kumabe, Jia Wang, Kazuki Ohnishi, Hirotaka Watanabe, Shugo Nitta, Yoshio Honda, Hiroshi Amano

Applied Physics Letters Vol. 122 ( 14 ) 2023.4

Temperature field, flow field and temporal fluctuations thereof in ammonothermal growth of bulk GaN - transition from dissolution stage to growth stage conditions Reviewed Open Access

S. Schimmel, D. Tomida, T. Ishiguro, Y. Honda, S. F. Chichibu, H. Amano

Materials Vol. 16 ( 5 ) page： 2016 1 - 27 2023.3

Red emission from InGaN active layer grown on nanoscale InGaN pseudosubstrates

Wentao Cai, Jia Wang, Jeong-Hwan Park, Yuta Furusawa, Heajeong Cheong, Shugo Nitta, Yoshio Honda, Markus Pristovsek, Hiroshi Amano

Japanese Journal of Applied Physics Vol. 62 ( 2 ) page： 020902 - 020902 2023.2

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

Abstract

We demonstrated nanoplatelet In x Ga1−x N pseudosubstrates with In content varying from 0 to 0.3 on low-dislocation-density GaN substrates. These nanoplatelets efficiently relax in-plane strain, thus allowing for the use of a thick active layer to reduce built-in polarization. The 15 nm thick InGaN active layers grown under the same conditions on these nanoplatelets showed a remarkable cathodoluminescence redshift from 460 to 617 nm, suggesting enhanced In incorporation efficiency in InGaN nanoplatelets with higher In content. Moreover, the 617 nm-emitting sample presented an imperceptible blueshift under excitation-power-dependent photoluminescence, indicating a weak polarization field introduced by the high-In-content pseudosubstrates and the thick active layer.

DOI： 10.35848/1347-4065/acb74c

Scanning electron microscope imaging by selective e-beaming using photoelectron beams from semiconductor photocathodes

Other Link： https://iopscience.iop.org/article/10.35848/1347-4065/acb74c/pdf

Tomohiro Nishitani, Yuta Arakawa, Shotaro Noda, Atsushi Koizumi, Daiki Sato, Haruka Shikano, Hokuto Iijima, Yoshio Honda, Hiroshi Amano

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B Vol. 40 ( 6 ) 2022.12

Language：English Publishing type：Research paper (scientific journal) Publisher：A V S AMER INST PHYSICS

Pulsed electron beams from a photocathode using an InGaN semiconductor have brought selectively scanning technology to scanning electron microscopes, where the electron beam irradiation intensity and area can be arbitrarily selected within the field of view in SEM images. The p-type InGaN semiconductor crystals grown in the metalorganic chemical vapor deposition equipment were used as the photocathode material for the electron beam source after the surface was activated to a negative electron affinity state in the electron gun under ultrahigh vacuum. The InGaN semiconductor photocathode produced a pulsed electron beam with a rise and fall time of 3 ns, consistent with the time structure of the irradiated pulsed laser used for the optical excitation of electrons. The InGaN photocathode-based electron gun achieved a total beam operation time of 1300 h at 15 mu A beam current with a downtime rate of 4% and a current stability of 0.033% after 23 cycles of surface activation and continuous beam operation. The InGaN photocathode-based electron gun has been installed in the conventional scanning electron microscope by replacing the original field emission gun. SEM imaging was performed by selective electron beaming, in which the scanning signal of the SEM system was synchronized with the laser for photocathode excitation to irradiate arbitrary regions in the SEM image at arbitrary intensity. The accuracy of the selection of regions in the SEM image by the selective electron beam was pixel by pixel at the TV scan speed (80 ns/pix, 25 frame/s) of the SEM.

DOI： 10.1116/6.0002111

High In content nitride sub-micrometer platelet arrays for long wavelength optical applications

Wentao Cai, Yuta Furusawa, Jia Wang, Jeong-Hwan Park, Yaqiang Liao, Hea-Jeong Cheong, Shugo Nitta, Yoshio Honda, Markus Pristovsek, Hiroshi Amano

Applied Physics Letters Vol. 121 ( 21 ) 2022.11

Language：English Publishing type：Research paper (scientific journal) Publisher：AIP Publishing

We demonstrate high, up to 30% In content InGaN sub-micrometer platelets on GaN by metalorganic vapor phase epitaxy. These InGaN platelets were selectively grown on flat GaN seeds formed in sub-micrometer-scale openings in a SiNx mask. The platelets were highly uniform without any dislocations or pits, with an atomically flat (0001) surface. The typical height was ∼120 nm, which significantly exceeded the normal critical layer thickness of a c-plane InGaN film. The strain state was comprehensively characterized by microbeam x-ray diffraction and transmission electron microscopy. Due to a gradual elastic relaxation of strain, the In content increased almost linearly from bottom to top because of the strong strain-dependent In incorporation. These platelets can serve as high-quality strain-relaxed templates for long wavelength micro-light-emitting diodes.

DOI： 10.1063/5.0120723

Substitutional diffusion of Mg into GaN from GaN/Mg mixture Open Access

Yuta Itoh, Shun Lu, Hirotaka Watanabe, Manato Deki, Shugo Nitta, Yoshio Honda, Atsushi Tanaka, Hiroshi Amano

Applied Physics Express Vol. 15 ( 11 ) page： 116505 - 116505 2022.11

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

Abstract

We evaluated Mg-diffusion into GaN from GaN/Mg mixture. The diffusion depth of Mg increased with diffusion temperature from 1100 °C to 1300 °C, whereas the Mg concentration remained constant at 2–3 × 1018 cm−3 independent of temperature. The estimated activation energy for Mg diffusion was 2.8 eV, from which the substitutional diffusion mechanism was predicted. Mg-diffused GaN samples showed p-type conductivity with a maximum hole mobility of 27.7 cm2 V−1 s−1, suggesting that substitutional diffusion contributes to Mg activation. This diffusion technique can be used to easily form p-type GaN and has potential as a p-type selective doping technique.

DOI： 10.35848/1882-0786/ac9c83

Other Link： https://iopscience.iop.org/article/10.35848/1882-0786/ac9c83/pdf

The photoemission characteristics of a NEA InGaN photocathode by simultaneously supplying Cs and O2 Open Access

Masahiro Kashima, Yuya Itokawa, Toshiya Kanai, Daiki Sato, Atsushi Koizumi, Hokuto Iijima, Tomohiro Nishitani, Yoshio Honda, Hiroshi Amano, Takashi Meguro

APPLIED SURFACE SCIENCE Vol. 599 2022.10

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER

A high quantum efficiency (QE) can be obtained on negative electron affinity (NEA) surfaces. It is well-known that NEA surfaces can be formed on semiconductor materials such as GaAs by the alternating supply of cesium (Cs) and oxygen (O2), which is called the yo-yo method. While GaN and related compounds such as InGaN are expected to realize an NEA photocathode with a long lifetime, the surface reactions between GaAs and nitride semiconductors are completely different with respect to the increasing rate of QE induced by the supply of O2. In addition, the surface processes of photoemission from NEA nitride semiconductors have not yet been elucidated. In the present study, a higher QE was achieved in InGaN by simultaneously supplying Cs and O2 instead of using the conventional yo-yo method. The possible Cs adsorption states in relation to the photoemission are also discussed based on the QE tendencies and the temperature programmed desorption (TPD) spectra of the NEA surfaces formed under elevated temperature conditions. This study suggests that the Cs oxide species, which is one of the key compounds for imparting the NEA nature, decomposes at approximately 350 degrees C and that the InGaN-Cs2O2 structure is a possible candidate for NEA photocathodes.

DOI： 10.1016/j.apsusc.2022.153882

High-energy computed tomography as a prospective tool for in situ monitoring of mass transfer processes inside high-pressure reactors - a case study on ammonothermal bulk crystal growth of nitrides including GaN Reviewed Open Access

Tuning the p-type doping of GaN over three orders of magnitude via efficient Mg doping during halide vapor phase epitaxy Reviewed Open Access

Kazuki Ohnishi, Naoki Fujimoto, Shugo Nitta, Hirotaka Watanabe, Shun Lu, Manato Deki, Yoshio Honda, Hiroshi Amano

Journal of Applied Physics Vol. 132 ( 14 ) 2022.10

S. Schimmel, M. Salamon, D. Tomida, S. Neumeier, T. Ishiguro, Y. Honda, S. F, Chichibu, H. Amano

Materials 15 (17) Vol. 15 ( 17 ) page： 6165 1 - 17 2022.9

Surface kinetics in halide vapor phase epitaxial growth of GaN layers on GaN (0001) freestanding substrates Reviewed Open Access

Kazuki Ohnishi, Naoki Fujimoto, Shugo Nitta, Hirotaka Watanabe, Yoshio Honda, Hiroshi Amano

Journal of Crystal Growth Vol. 592 page： 126749 - 126749 2022.8

Weak metastability of AlxGa1−xN (x = 13/24, 15/24, 17/24) shown by analyzing AlGaN grown on AlN with dense macrosteps Reviewed International journal

Akira Hirano, Yosuke Nagasawa, Masamichi Ippommatsu, Hideki Sako, Ai Hashimoto, Ryuichi Sugie, Yoshio Honda, Hiroshi Amano, Kazunobu Kojima, Shigefusa F. Chichibu

Applied Physics Express Vol. 15 ( 7 ) page： 075505 1 - 5 2022.7

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

Abstract

Energy-dispersive X-ray signals calibrated by Rutherford backscattering indicated the generation of Al13/24Ga11/24N in Ga-rich stripes in a nonflat Al0.58Ga0.42N layer. Also, the CL peak wavelengths of ∼259 and 272 nm also showed the generation of Al15/24Ga9/24N and Al13/24Ga11/24N in Al-rich zones and Ga-rich stripes, respectively. The wavelength of a strong CL peak at ∼246 nm, which was observed from the Al0.7Ga0.3N layer in our previous study, is also considered to correspond to the near-band-emission wavelengths of Al17/24Ga7/24N. In particular, the stronger reproducibility of metastable Al15/24Ga9/24N generation was confirmed, in agreement with the computed predictions by other research groups.

DOI： 10.35848/1882-0786/ac79a1

Space–Charge Profiles and Carrier Transport Properties in Dopant‐Free GaN‐Based p‐n Junction Formed by Distributed Polarization Doping

Other Link： https://iopscience.iop.org/article/10.35848/1882-0786/ac79a1/pdf

Takeru Kumabe, Seiya Kawasaki, Hirotaka Watanabe, Shugo Nitta, Yoshio Honda, Hiroshi Amano

physica status solidi (RRL) – Rapid Research Letters Vol. 16 ( 7 ) 2022.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley

Herein, the operation of dopant‐free GaN‐based p‐n junctions formed by distributed polarization doping (DPD) is experimentally demonstrated and their space charge profiles and carrier transport properties are investigated. The device exhibits ideal space charge profiles explained by polarization effects and demonstrates the excellent controllability of DPD. In addition, it shows rectification and electroluminescence under forward‐biased conditions. The carrier transport properties could be explained by the conventional recombination/diffusion model used for impurity‐doped p‐n junctions. Repeatable breakdowns are also observed in all devices and the temperature‐dependent breakdown voltages reveal that the breakdowns are caused by avalanche multiplication, which is also the same as those reported in impurity‐doped GaN p‐n diodes. These results indicate that DPD is a promising doping technology for GaN‐based power devices overcoming any issues associated with conventional impurity doping.

DOI： 10.1002/pssr.202200127

Dual-peak electroluminescence spectra generated from Aln/12Ga1-n/12N (n=2, 3, 4) for AlGaN-based LEDs with nonflat quantum wells Reviewed

Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/pssr.202200127

Y. Nagasawa, K. Kojima, A. Hirano, M. Ippommatsu, Y. Honda, H. Amano, S. F. Chichibu

Journal of Physics D: Applied Physics Vol. 55 ( 25 ) page： 255102 1 - 11 2022.6

“Regrowth-free” fabrication of high-current-gain AlGaN/GaN heterojunction bipolar transistor with N-p-n configuration Open Access

Takeru Kumabe, Hirotaka Watanabe, Yuto Ando, Atsushi Tanaka, Shugo Nitta, Yoshio Honda, Hiroshi Amano

Applied Physics Express Vol. 15 ( 4 ) page： 046506 - 046506 2022.4

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

Abstract

An AlGaN/GaN heterojunction bipolar transistor (HBT) with N-p-n configuration was fabricated by the “regrowth-free” method, resulting in a contamination-free emitter-base AlGaN/GaN heterojunction. The low-bias-power-based low-damage inductively coupled plasma–reactive ion etching was employed in this study for emitter mesa definition instead of the conventional selective-area-regrowth technique. The method successfully minimized the etching-induced damage in the p-GaN base layer and the contamination at the emitter-base AlGaN/GaN heterojunction. Consequently, the fabricated device exhibited a high current gain of 25, the highest current density of 15.0 kA cm−2, and the lowest on-state voltage offset of 0.75 V ever reported for AlGaN/GaN HBTs.

DOI： 10.35848/1882-0786/ac6197

Structural design optimization of 279 nm wavelength AlGaN homojunction tunnel junction deep-UV light-emitting diode Open Access

Other Link： https://iopscience.iop.org/article/10.35848/1882-0786/ac6197/pdf

Kengo Nagata, Satoshi Anada, Hiroshi Miwa, Shinichi Matsui, Shinya Boyama, Yoshiki Saito, Maki Kushimoto, Yoshio Honda, Tetsuya Takeuchi, Hiroshi Amano

Applied Physics Express Vol. 15 ( 4 ) page： 044003 - 044003 2022.4

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

Abstract

We demonstrated the structural optimization of AlGaN tunnel junction (TJ) deep-ultraviolet light-emitting diodes by changing the thickness and impurity concentrations of p+-type and n+-type AlGaN constituting the TJ. By decreasing the total thickness of the TJ to 23 nm, the operating voltage reached a minimum of 8.8 V at 63 A cm−2. Further decrease in TJ thickness markedly increases the operating voltage. This finding implies that the depletion layer width becomes greater than the TJ thickness if it is smaller than 12 nm. Therefore, we conclude that the TJ thickness must be greater than the depletion layer width.

DOI： 10.35848/1882-0786/ac60c7

Sputtered polycrystalline MgZnO/Al reflective electrodes for enhanced light emission in AlGaN-based homojunction tunnel junction DUV-LED Open Access

Other Link： https://iopscience.iop.org/article/10.35848/1882-0786/ac60c7/pdf

Taichi Matsubara, Kengo Nagata, Maki Kushimoto, Shigekazu Tomai, Satoshi Katsumata, Yoshio Honda, Hiroshi Amano

Applied Physics Express Vol. 15 ( 4 ) 2022.4

Language：English Publishing type：Research paper (scientific journal)

In this study, we enhanced the emission power of AlGaN-based tunnel junction deep-ultraviolet LEDs (TJ LEDs) by using a MgZnO and aluminum stacked structure as UV reflective electrodes on the anode side. The emission wavelength of the fabricated TJ LED was 284 nm, and the emission power was 57.3 mW at 63 A cm-2. The polycrystalline MgZnO enabled both conductivity and UV transmittance to be achieved, approximately doubling with a reflectance of the fabricated TJ LED at 284 nm compared to conventional TJ LED with Ti/Al. These factors contributed to the increased emission power of TJ LEDs.

DOI： 10.35848/1882-0786/ac5acf

Visualization of depletion layer in AlGaN homojunction p–n junction Open Access

Kengo Nagata, Satoshi Anada, Yoshiki Saito, Maki Kushimoto, Yoshio Honda, Tetsuya Takeuchi, Kazuo Yamamoto, Tsukasa Hirayama, Hiroshi Amano

Applied Physics Express Vol. 15 ( 3 ) 2022.3

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

<title>Abstract</title>
We analyzed the p–n junction of an aluminum gallium nitride (AlGaN) homojunction tunnel junction (TJ) deep-ultraviolet light-emitting diode by phase-shifting electron holography. We clearly obtained a phase image reflecting the band alinement of the p–n homojunction and derived a depletion layer width of approximately 10 nm. In addition, the observed depletion layer width for the AlGaN TJ was in good agreement with the simulated one reflecting the diffusion profile of Mg and Si, thus enabling a discussion on the electrical conduction mechanism for an AlGaN p-n junction.

DOI： 10.35848/1882-0786/ac53e2

Other Link： https://iopscience.iop.org/article/10.35848/1882-0786/ac53e2/pdf

Effect of beam current on defect formation by high-temperature implantation of Mg ions into GaN Open Access

Yuta Itoh, Hirotaka Watanabe, Yuto Ando, Emi Kano, Manato Deki, Shugo Nitta, Yoshio Honda, Atsushi Tanaka, Nobuyuki Ikarashi, Hiroshi Amano

Applied Physics Express Vol. 15 ( 2 ) 2022.2

Language：English Publishing type：Research paper (scientific journal)

We evaluated the beam current dependence of defect formation during Mg ion implantation into GaN at a high temperature of 1100 °C with two beam currents. Photoluminescence spectra suggest that low-beam-current implantation reduced the vacancy concentration and activated Mg to a greater extent. Moreover, scanning transmission electron microscopy analysis showed that low-beam-current implantation reduced the density of Mg segregation defects with inactive Mg and increased the density of intrinsic dislocation loops, suggesting decreases in the densities of Ga and N vacancies. The formation of these defects depended on beam current, which is an important parameter for defect suppression.

DOI： 10.35848/1882-0786/ac481b

Threshold increase and lasing inhibition due to hexagonal-pyramid-shaped hillocks in AlGaN-based DUV laser diodes on single-crystal AlN substrate Open Access

Maki Kushimoto, Ziyi Zhang, Yoshio Honda, Leo J. Schowalter, Chiaki Sasaoka, Hiroshi Amano

Japanese Journal of Applied Physics Vol. 61 ( 1 ) page： 010601 - 010601 2022.1

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

Abstract

The presence of hexagonal-pyramid-shaped hillocks (HPHs) in AlGaN epitaxial films affects device characteristics; this effect is significant in DUV laser diodes (LDs) on AlN substrates, where the presence of HPHs under the p-electrode increases the threshold current density and inhibits the lasing. In this study, we investigated the difference between the lasing characteristics of LDs with and without HPHs. It was found that in the presence of HPHs, the threshold excitation power density increased and the slope efficiency decreased by optical excitation. To investigate the cause of these phenomena, we performed structural, optical, and electrical analyses of the HPHs. Various imaging techniques were used to directly capture the characteristics of the HPHs. As a result, we concluded that HPHs cause the degradation of LD characteristics due to a combination of structural, optical, and electrical factors.

DOI： 10.35848/1347-4065/ac3a1d

Discrete wavelengths observed in electroluminescence originating from Al1/2Ga1/2N and Al1/3Ga2/3N created in nonflat AlGaN quantum wells Reviewed

Other Link： https://iopscience.iop.org/article/10.35848/1347-4065/ac3a1d/pdf

Ohmic contact on low-doping-density p-type GaN with nitrogen-annealed Mg Reviewed Open Access

Shun Lu, Manato Deki, Jia Wang, Kazuki Ohnishi, Yuto Ando, Takeru Kumabe, Hirotaka Watanabe, Shugo Nitta, Yoshio Honda, Hiroshi Amano

Applied Physics Letters Vol. 119 ( 24 ) page： 242104 - 242104 2021.12

Yosuke Nagasawa, Kazunobu Kojima, Akira Hirano, Hideki Sako, Ai Hashimoto, Ryuichi Sugie, Masamichi Ippommatsu, Yoshio Honda, Hiroshi Amano, Shigefusa F Chichibu

Journal of Physics D: Applied Physics Vol. 54 ( 48 ) page： 485107-1 - 10 2021.12

Multiple electron beam generation from InGaN photocathode

Daiki Sato, Haruka Shikano, Atsushi Koizumi, Tomohiro Nishitani, Yoshio Honda, Hiroshi Amano

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B Vol. 39 ( 6 ) 2021.12

Language：English Publishing type：Research paper (scientific journal) Publisher：A V S AMER INST PHYSICS

In this study, we generated 25 multielectron beam (MEB) using an InGaN photocathode with a negative electron affinity state irradiating with 25 multilaser beam. The uniformity of the MEB and the total electron beam current were evaluated. A laser beam was split into 25 laser beams using a spatial light modulator. The coefficient of variation (CV) of laser power was 20%. The CV of quantum efficiency was 1.1%. The CV of electron beam current was 12%, and the total current was about 1.2 mu A. These results will enhance the development of the MEB-defect inspection using the InGaN photocathode.

DOI： 10.1116/6.0001272

Vertical GaN p+-n junction diode with ideal avalanche capability grown by halide vapor phase epitaxy Reviewed Open Access

Kazuki Ohnishi, Seiya Kawasaki, Naoki Fujimoto, Shugo Nitta, Hirotaka Watanabe, Yoshio Honda, Hiroshi Amano

Applied Physics Letters Vol. 119 ( 15 ) page： 152102 - 152102 2021.10

Effective neutron detection using vertical-type BGaN diodes Reviewed

Takayuki Nakano, Ken Mochizuki, Takuya Arikawa, Hisaya Nakagawa, Shigeyoshi Usami, Yoshio Honda, Hiroshi Amano, Adrian Vogt, Sebastian Schütt, Michael Fiederle, Kazunobu Kojima, Shigefusa F. Chichibu, Yoku Inoue, Toru Aoki

Journal of Applied Physics Vol. 130 ( 12 ) page： 124501-1 - 10 2021.9

Language：English Publishing type：Research paper (scientific journal) Publisher：AIP Publishing

In this study, vertical-type thick BGaN PIN diodes were successfully fabricated to improve the neutron capture rate of BGaN diodes by improving the BGaN epitaxial growth technique. In this technique, 5-μm-thick epitaxial growth was achieved using trimethylboron as a B metal-organic source, which suppressed the gas-phase reaction. The α-particle energy spectrum, the neutron pulse signal, and the residual energy of particles emitted from a neutron capture reaction were measured using the fabricated BGaN diodes by performing radiation detection measurements. The detected signal position in the neutron detection signal spectrum was similar to that of 2.3 MeV α-particles. These results indicate that vertical-type BGaN diodes can be used as effective neutron detectors.

DOI： 10.1063/5.0051053

Smart-cut-like laser slicing of GaN substrate using its own nitrogen Open Access

Atsushi Tanaka, Ryuji Sugiura, Daisuke Kawaguchi, Toshiki Yui, Yotaro Wani, Tomomi Aratani, Hirotaka Watanabe, Hadi Sena, Yoshio Honda, Yasunori Igasaki, Hiroshi Amano

Scientific Reports Vol. 11 ( 1 ) page： 17949 2021.9

Language：English Publishing type：Research paper (scientific journal)

We have investigated the possibility of applying lasers to slice GaN substrates. Using a sub-nanosecond laser with a wavelength of 532 nm, we succeeded in slicing GaN substrates. In the laser slicing method used in this study, there was almost no kerf loss, and the thickness of the layer damaged by laser slicing was about 40 µm. We demonstrated that a standard high quality homoepitaxial layer can be grown on the sliced surface after removing the damaged layer by polishing.

DOI： 10.1038/s41598-021-97159-w

Gallium nitride wafer slicing by a sub-nanosecond laser: effect of pulse energy and laser shot spacing Open Access

Hadi Sena, Atsushi Tanaka, Yotaro Wani, Tomomi Aratani, Toshiki Yui, Daisuke Kawaguchi, Ryuji Sugiura, Yoshio Honda, Yasunori Igasaki, Hiroshi Amano

Applied Physics A: Materials Science and Processing Vol. 127 ( 9 ) 2021.9

Language：English Publishing type：Research paper (scientific journal)

Gallium nitride (GaN)-based devices surpass the traditional silicon-based power devices in terms of higher breakdown voltage, faster-switching speed, higher thermal conductivity, and lower on-resistance. However, heteroepitaxial GaN growths like GaN on sapphire are not suitable for power devices due to the threading dislocation densities as high as 108/cm2. Recently, homoepitaxial GaN growth has become possible thanks to the native GaN substrates with dislocation densities in the order of 104/cm2 but the extremely high cost of the GaN substrates makes the homoepitaxy method unacceptable for industrial applications, and the slicing of wafers for reusing them is an effective solution for cost reduction. In this study, we will investigate a route for slicing the GaN single crystal substrate by controlling the laser pulse energy and changing the distance between each laser shot. The 2D and 3D crack propagations are observed by a multiphoton confocal microscope, and the cross section of samples is observed by a scanning electron microscope (SEM). The results showed that two types of radial and lateral cracking occurred depending on the pulse energy and shot pitch, and controlling them was of importance for attaining a smooth GaN substrate slicing. Cross-sectional SEM images showed that at suitable pulse energy and distance, crack propagation could be controlled with respect to the irradiation plane.

DOI： 10.1007/s00339-021-04808-y

Reduction in operating voltage of AlGaN homojunction tunnel junction deep-UV light-emitting diodes by controlling impurity concentrations Open Access

Kengo Nagata, Hiroaki Makino, Hiroshi Miwa, Shinichi Matsui, Shinya Boyama, Yoshiki Saito, Maki Kushimoto, Yoshio Honda, Tetsuya Takeuchi, Hiroshi Amano

Applied Physics Express Vol. 14 ( 8 ) 2021.8

Language：English Publishing type：Research paper (scientific journal)

We reduced the operating voltage of AlGaN homojunction tunnel junction (TJ) deep-ultraviolet (UV) light-emitting diodes (LEDs) by two approaches: the suppression of carbon incorporation and the doping of a high concentration of silicon in an n+-AlGaN layer. The AlGaN homojunction TJ deep-UV LEDs had a significantly reduced forward voltage upon suppressing the incorporation of carbon in the n+-AlGaN layer. The suppression of electron compensation by carbon in nitrogen sites and the doping of a high concentration of silicon in an n+-AlGaN layer are important for reducing the operating voltage of AlGaN homojunction TJ deep-UV LEDs.

DOI： 10.35848/1882-0786/ac0fb6

Impact of gate electrode formation process on Al<inf>2</inf>O<inf>3</inf>/GaN interface properties and channel mobility

Yuto Ando, Manato Deki, Hirotaka Watanabe, Noriyuki Taoka, Atsushi Tanaka, Shugo Nitta, Yoshio Honda, Hisashi Yamada, Mitsuaki Shimizu, Tohru Nakamura, Hiroshi Amano

Applied Physics Express Vol. 14 ( 8 ) 2021.8

Language：English Publishing type：Research paper (scientific journal)

The interface properties of GaN metal-insulator-semiconductor (MIS) structures with a gate electrode metal deposited by electron beam (EB) or resistive heating evaporation were investigated. Also, the impact of the interface properties on the channel mobility in GaN MIS field-effect transistors was investigated. It was confirmed that interface charges including both interface states and positive fixed charges were introduced to an Al2O3/GaN interface by the formation of a gate electrode by EB evaporation. Consequently, the introduced interface charges degraded the electron mobility in the MIS channel.

DOI： 10.35848/1882-0786/ac0ffa

Improving light output power of AlGaN-based deep-ultraviolet light-emitting diodes by optimizing the optical thickness of p-layers

Yusuke Matsukura, Tetsuhiko Inazu, Cyril Pernot, Naoki Shibata, Maki Kushimoto, Manato Deki, Yoshio Honda, Hiroshi Amano

Applied Physics Express Vol. 14 ( 8 ) page： 084004 - 084004 2021.8

Electrical properties and structural defects of p-type GaN layers grown by halide vapor phase epitaxy Reviewed

Kazuki Ohnishi, Yuki Amano, Naoki Fujimoto, Shugo Nitta, Hirotaka Watanabe, Yoshio Honda, Hiroshi Amano

Journal of Crystal Growth Vol. 566 page： 126173 - 126173 2021.7

Vertical GaN-on-GaN nanowire Schottky barrier diodes by top-down fabrication approach

Yaqiang Liao, Tao Chen, Jia Wang, Yuto Ando, Wentao Cai, Xu Yang, Hirotaka Watanabe, Jun Hirotani, Atsushi Tanaka, Shugo Nitta, Yoshio Honda, Kevin J. Chen, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 60 ( 7 ) 2021.7

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

An optimized top-down approach was utilized to fabricate vertical GaN-on-GaN nanowire Schottky barrier diodes (NWSBDs) in this letter. The suppressed reverse leakage current and enhanced breakdown voltage (BV) of the vertical GaN NWSBDs are attributed to the reduced electric field at the interface of the Schottky junction achieved through the dielectric reduced surface field technique. As-fabricated NWSBD delivers a low turn-on voltage of 0.80 V, a near-unity ideality factor of 1.04, along with a soft BV of 480 V. The measured soft BV is comparable with the avalanche BV of the p-n diode with a similar net doping concentration in the drift region.

DOI： 10.35848/1347-4065/ac06b5

Etching-induced damage in heavily Mg-doped p-type GaN and its suppression by low-bias-power inductively coupled plasma-reactive ion etching Open Access

Takeru Kumabe, Yuto Ando, Hirotaka Watanabe, Manato Deki, Atsushi Tanaka, Shugo Nitta, Yoshio Honda, Hiroshi Amano

Japanese Journal of Applied Physics Vol. 60 ( SB ) 2021.5

Language：English Publishing type：Research paper (scientific journal)

Inductively coupled plasma–reactive ion etching (ICP–RIE)-induced damage in heavily Mg-doped p-type GaN ([Mg] = 2 × 1019 cm−3) was investigated by low-temperature photoluminescence (PL) and depth-resolved cathodoluminescence (CL) spectroscopy. From PL measurements, we found broad yellow luminescence (YL) with a maximum at around 2.2–2.3 eV, whose origin was considered to be isolated nitrogen vacancies (VN), only in etched samples. The depth-resolved CL spectroscopy revealed that the etching-induced YL was distributed up to the electron-beam penetration depth of around 200 nm at a high ICP–RIE bias power (Pbias). Low-bias-power (low-Pbias) ICP–RIE suppressed the YL and its depth distribution to levels similar to those of an unetched sample, and a current–voltage characteristic comparable to that of an unetched sample was obtained for a sample etched with Pbias of 2.5 W.

DOI： 10.35848/1347-4065/abd538

Impact of heat treatment process on threshold current density in AlGaN-based deep-ultraviolet laser diodes on AlN substrate Open Access

Maki Kushimoto, Ziyi Zhang, Naoharu Sugiyama, Yoshio Honda, Leo J. Schowalter, Chiaki Sasaoka, Hiroshi Amano

Applied Physics Express Vol. 14 ( 5 ) page： 051003 - 051003 2021.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

Abstract

The electroluminescence (EL) uniformity of AlGaN-based deep UV laser diodes on AlN substrate was analyzed by using the EL imaging technique. Although nonuniform EL patterns were observed, the uniformity was improved by changing the position of the p-electrode. The threshold current density was also reduced by suppressing the inhomogeneity of the EL. Cathodoluminescence analysis revealed that the cause of the non-uniformity is the degradation of the active layer and the nonuniformity emission formed by rapid thermal annealing at high temperature after mesa structure formation.

DOI： 10.35848/1882-0786/abf443

Discrete AlN mole fraction of n/12 (n = 4–8) in Ga-rich zones functioning as electron pathways created in nonflat AlGaN layers grown on high-miscut sapphire substrates

Other Link： https://iopscience.iop.org/article/10.35848/1882-0786/abf443/pdf

Yosuke Nagasawa, Akira Hirano, Masamichi Ippommatsu, Hideki Sako, Ai Hashimoto, Ryuichi Sugie, Yoshio Honda, Hiroshi Amano, Isamu Akasaki, Kazunobu Kojima, Shigefusa F. Chichibu

Journal of Applied Physics Vol. 129 ( 16 ) page： 164503 - 164503 2021.4

Experimental demonstration of GaN IMPATT diode at X-band

Seiya Kawasaki, Yuto Ando, Manato Deki, Hirotaka Watanabe, Atsushi Tanaka, Shugo Nitta, Yoshio Honda, Manabu Arai, Hiroshi Amano

Applied Physics Express Vol. 14 ( 4 ) 2021.4

Language：English Publishing type：Research paper (scientific journal)

We report the first experimental demonstration of microwave oscillation in GaN impact ionization avalanche time transit (IMPATT) diodes at the X-band. The device used in this study is a single drift diode with a p+–n simple abrupt junction and vertical mesa termination. The reverse I–V characteristic of the diode shows low leakage current, clear avalanche breakdown, and high avalanche capability, as required for IMPATT operation. Microwave testing is performed in an X-band waveguide circuit with a reduced-height waveguide resonant cavity. Oscillations are observed at 9.52 GHz at a power of ∼56 mW.

DOI： 10.35848/1882-0786/abe3dc

Numerical Simulation of Ammonothermal Crystal Growth of GaN—Current State, Challenges, and Prospects Open Access

Saskia Schimmel, Daisuke Tomida, Tohru Ishiguro, Yoshio Honda, Shigefusa Chichibu, Hiroshi Amano

Crystals Vol. 11 ( 4 ) page： 356 - 356 2021.4

Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG

Numerical simulations are a valuable tool for the design and optimization of crystal growth processes because experimental investigations are expensive and access to internal parameters is limited. These technical limitations are particularly large for ammonothermal growth of bulk GaN, an important semiconductor material. This review presents an overview of the literature on simulations targeting ammonothermal growth of GaN. Approaches for validation are also reviewed, and an overview of available methods and data is given. Fluid flow is likely in the transitional range between laminar and turbulent; however, the time-averaged flow patterns likely tend to be stable. Thermal boundary conditions both in experimental and numerical research deserve more detailed evaluation, especially when designing numerical or physical models of the ammonothermal growth system. A key source of uncertainty for calculations is fluid properties under the specific conditions. This originates from their importance not only in numerical simulations but also in designing similar physical model systems and in guiding the selection of the flow model. Due to the various sources of uncertainty, a closer integration of numerical modeling, physical modeling, and the use of measurements under ammonothermal process conditions appear to be necessary for developing numerical models of defined accuracy.

DOI： 10.3390/cryst11040356

Fabrication of GaN cantilever on GaN substrate by photo-electrochemical etching

Takehiro Yamada, Yuto Ando, Hirotaka Watanabe, Yuta Furusawa, Atsushi Tanaka, Manato Deki, Shugo Nitta, Yoshio Honda, Jun Suda, Hiroshi Amano

Applied Physics Express Vol. 14 ( 3 ) 2021.3

Language：English Publishing type：Research paper (scientific journal)

Photo-electrochemical (PEC) etching is a promising technique for fabricating GaN microelectromechanical systems devices. In this study, we demonstrate the fabrication of GaN cantilevers by the bandgap-selective PEC etching of an InGaN superlattice sacrificial layer. By using an InGaN superlattice as a sacrifice layer, we found the PEC etching rate became higher than using a normal InGaN layer. As a result, the InGaN superlattice was completely etched and we fabricated GaN-based cantilevers whose resonance characteristics were measured. The Young’s modulus of GaN was determined from the resonance characteristics of GaN cantilevers to be the same as the highest value reported previously.

DOI： 10.35848/1882-0786/abe657

Boundary Conditions for Simulations of Fluid Flow and Temperature Field during Ammonothermal Crystal Growth—A Machine-Learning Assisted Study of Autoclave Wall Temperature Distribution Reviewed Open Access

Saskia Schimmel, Daisuke Tomida, Makoto Saito, Quanxi Bao, Toru Ishiguro, Yoshio Honda, Shigefusa Chichibu, Hiroshi Amano

Crystals Vol. 11 ( 3 ) page： 254 -1 - 27 2021.3

Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG

Thermal boundary conditions for numerical simulations of ammonothermal GaN crystal growth are investigated. A global heat transfer model that includes the furnace and its surroundings is presented, in which fluid flow and thermal field are treated as conjugate in order to fully account for convective heat transfer. The effects of laminar and turbulent flow are analyzed, as well as those of typically simultaneously present solids inside the autoclave (nutrient, baffle, and multiple seeds). This model uses heater powers as a boundary condition. Machine learning is applied to efficiently determine the power boundary conditions needed to obtain set temperatures at specified locations. Typical thermal losses are analyzed regarding their effects on the temperature distribution inside the autoclave and within the autoclave walls. This is of relevance because autoclave wall temperatures are a convenient choice for setting boundary conditions for simulations of reduced domain size. Based on the determined outer wall temperature distribution, a simplified model containing only the autoclave is also presented. The results are compared to those observed using heater-long fixed temperatures as boundary condition. Significant deviations are found especially in the upper zone of the autoclave due to the important role of heat losses through the autoclave head.

DOI： 10.3390/cryst11030254

Development of pulsed TEM equipped with nitride semiconductor photocathode for high-speed observation and material nanofabrication Reviewed Open Access

Hidehiro Yasuda, Tomohiro Nishitani, Shuhei Ichikawa, Shuhei Hatanaka, Yoshio Honda, Hiroshi Amano

Quantum Beam Science Vol. 5 ( 1 ) page： 5 - 5 2021.3

Language：English Publishing type：Research paper (scientific journal) Publisher：{MDPI} {AG}

The development of pulsed electron sources is applied to electron microscopes or electron beam lithography and is effective in expanding the functions of such devices. The laser photocathode can generate short pulsed electrons with high emittance, and the emittance can be increased by changing the cathode substrate from a metal to compound semiconductor. Among the substrates, nitride-based semiconductors with a negative electron affinity (NEA) have good advantages in terms of vacuum environment and cathode lifetime. In the present study, we report the development of a photocathode electron gun that utilizes photoelectron emission from a NEA-InGaN substrate by pulsed laser excitation, and the purpose is to apply it to material nanofabrication and high-speed observation using a pulsed transmission electron microscope (TEM) equipped with it.

DOI： 10.3390/qubs5010005

Suppression of the regrowth interface leakage current in AlGaN/GaN HEMTs by unactivated Mg doped GaN layer Open Access

T. Liu, H. Watanabe, S. Nitta, J. Wang, G. Yu, Y. Ando, Y. Honda, H. Amano, A. Tanaka, Y. Koide

Applied Physics Letters Vol. 118 ( 7 ) 2021.2

Language：English Publishing type：Research paper (scientific journal)

The leakage current caused by the Si pileup at the regrowth interface of AlGaN/GaN high electron mobility transistors (HEMTs) is significantly suppressed by the semi-insulating Mg-doped GaN layer. Mg is unintentionally doped and can be originated from the graphite susceptor of metal organic vapor phase epitaxy. Before regrowth of the AlGaN/GaN heterostructure, the GaN template is treated with hydrochloric acid (HCl) and hydrogen peroxide/potassium hydroxide (H2O2/KOH) solution to promote the adsorption of Mg on the GaN surface. The Mg-doped GaN channel layer is highly resistive due to the passivation of hydrogen. The p-n junction formed by the weakly p-type Mg-doped GaN layer and the n-type Si pileup layer depletes the excess electrons at the regrowth interface. As a result, the off-state drain leakage current of the HEMT device can be decreased by two orders of magnitude at 40 V.

DOI： 10.1063/5.0034584

Electrical properties of GaN metal-insulator-semiconductor field-effect transistors with Al2O3/GaN interfaces formed on vicinal Ga-polar and nonpolar surfaces

Optical properties of neodymium ions in nanoscale regions of gallium nitride: erratum Open Access

Shin-Ichiro Sato, Manato Deki, Hirotaka Watanabe, Shugo Nitta, Yoshio Honda, Tomoaki Nishimura, Brant C. Gibson, Andrew D. Greentree, Hiroshi Amano, Takeshi Ohshima

Optical Materials Express Vol. 11 ( 2 ) page： 524 - 524 2021.2

Yuto Ando, Kentaro Nagamatsu, Manato Deki, Noriyuki Taoka, Atsushi Tanaka, Shugo Nitta, Yoshio Honda, Tohru Nakamura, Hiroshi Amano

Applied Physics Letters Vol. 117 ( 24 ) page： 242104 - 242104 2020.12

Detailed analysis of Ga-rich current pathways using n-Al0.7Ga0.3N layer grown on AlN template with dense macrosteps

Yosuke Nagasawa, Akira Hirano, Masamichi Ipponmatsu, Hideki Sako, Ai Hashimoto, Ryuichi Sugie, Yoshio Honda, Hiroshi Amano, Isamu Akasaki, Kazunobu Kojima, Shigefusa F. Chichibu

Applied Physics Express Vol. 13 ( 12 ) 2020.12

Epitaxial Combination of Two-Dimensional Hexagonal Boron Nitride with Single-Crystalline Diamond Substrate

Xu Yang, Markus Pristovsek, Shugo Nitta, Yuhuai Liu, Yoshio Honda, Yasuo Koide, Hiroshi Kawarada, Hiroshi Amano

ACS APPLIED MATERIALS & INTERFACES Vol. 12 ( 41 ) page： 46466 - 46475 2020.10

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Hexagonal boron nitride (hBN) and diamond are promising materials for next-generation electronics and optoelectronics. However, their combination is rarely reported. In this study, we for the first time demonstrate the success to direct growth of two-dimensional (2D) hBN crystal layers on diamond substrates by metalorganic vapor phase epitaxy. Compared with the disordered growth we found on diamond (100), atomic force microscopy, X-ray diffraction, and transmission electron microscopy results all support 2D hBN with highly oriented lattice formation on diamond (111). Also, the epitaxial relationship between hBN and diamond (111) substrate is revealed to be [0 0 0 1](hBN) // [1 1 1](diamond) and [1 0 (1) over bar 0](hBN) // [1 1 (2) over bar](diamond) The valence band offset at hBN/diamond (111) heterointerface determined by X-ray photoelectron spectroscopy is 1.4 +/- 0.2 eV, thus yielding a conduction band offset of 1.0 +/- 0.2 eV and type II staggered band alignment with a bandgap of 5.9 eV assumed for hBN. Furthermore, prior thermal cleaning of diamond in a pure H-2 atmosphere smoothens the surface for well-ordered layered hBN epitaxy, while thermal cleaning in a mixed H-2 and NH3 atmosphere etches the diamond surface, creating many small faceted pits that destroy the following epitaxy of hBN.

DOI： 10.1021/acsami.0c11883

PubMed

Optical properties of neodymium ions in nanoscale regions of gallium nitride Open Access

Shin-Ichiro Sato, Manato Deki, Hirotaka Watanabe, Shugo Nitta, Yoshio Honda, Tomoaki Nishimura, Brant C. Gibson, Andrew D. Greentree, Hiroshi Amano, Takeshi Ohshima

OPTICAL MATERIALS EXPRESS Vol. 10 ( 10 ) page： 2614 - 2623 2020.10

Language：English Publishing type：Research paper (scientific journal) Publisher：OPTICAL SOC AMER

Wide bandgap semiconductors are increasingly important for bioimaging applications, as they can possess good biocompatibility and host a large range of fluorescent defects spanning the visible to infrared. Gallium nitride is one promising host for photostable fluorophores. In particular, neodymium (Nd)-doped gallium nitride (GaN) shows bright near-infrared fluorescence and narrow room temperature linewidth and is therefore a candidate material for fluorescent probes for bioimaging. To explore the conditions necessary to generate biomarkers based on Nd:GaN, this paper reports the room temperature photoluminescence (FL) properties of small ensembles of Nd ions implanted into the nanoscale regions of GaN epilayers. The minimum volume of Nd-implanted GaN that can be optically detected in this study is about 8x10(4) nm(3) and the minimum detected ensemble of Nd ions is about 4x10(3), although not all of implanted Nd ions activate as luminescence centers. We show from the PL excitation spectra that the strongest resonant excitation appears at 619 nm, attributed to the I-4(9/2) -> (4)G(5/2) ((4)G(7/)(2)) transition in the 4f-shell. We measure the luminescence lifetime to be several tens of microseconds. We also identify the presence of a different excitation mechanism from the resonant excitation when excited below 510 nm (above 2.43 eV). (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

DOI： 10.1364/OME.401765

Photoluminescence properties of implanted Praseodymium into Gallium Nitride at elevated temperatures Reviewed

Shin-ichiro Sato, Manato Deki, Tomoaki Nishimura, Hiroshi Okada, Hirotaka Watanabe, Shugo Nitta, Yoshio Honda, Hiroshi Amano, Takeshi Ohshima

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms Vol. 479 page： 7 - 12 2020.9

Low interface state densities at Al2O3/GaN interfaces formed on vicinal polar and non-polar surfaces Open Access

Yuto Ando, Kentaro Nagamatsu, Manato Deki, Noriyuki Taoka, Atsushi Tanaka, Shugo Nitta, Yoshio Honda, Tohru Nakamura, Hiroshi Amano

Applied Physics Letters Vol. 117 ( 10 ) page： 102102 - 102102 2020.9

Thermodynamic analysis of the gas phase reaction of Mg-doped GaN growth by HVPE using MgO Reviewed

Tomoya Kimura, Kazuki Ohnishi, Yuki Amano, Naoki Fujimoto, Masaaki Araidai, Shugo Nitta, Yoshio Honda, Hiroshi Amano, Yoshihiro Kangawa, Kenji Shiraishi

Japanese Journal of Applied Physics Vol. 59 ( 8 ) page： 088001 - 088001 2020.8

Pulsed-flow growth of polar, semipolar and nonpolar AlGaN Reviewed

Dinh Duc V, Hu Nan, Honda Yoshio, Amano Hiroshi, Pristovsek Markus

JOURNAL OF MATERIALS CHEMISTRY C Vol. 8 ( 25 ) page： 8668 - 8675 2020.7

Screw dislocation that converts p-type GaN to n-type: Microscopic study on Mg condensation and leakage current in p–n diodes Open Access

T. Nakano, Y. Harashima, K. Chokawa, K. Shiraishi, A. Oshiyama, Y. Kangawa, S. Usami, N. Mayama, K. Toda, A. Tanaka, Y. Honda, H. Amano

Applied Physics Letters Vol. 117 ( 1 ) page： 012105 - 012105 2020.7

Change of high-voltage conduction mechanism in vertical GaN-on-GaN Schottky diodes at elevated temperatures Reviewed

Sandupatla Abhinay, Arulkumaran Subramaniam, Ng Geok Ing, Ranjan Kumud, Deki Manato, Nitta Shugo, Honda Yoshio, Amano Hiroshi

APPLIED PHYSICS EXPRESS Vol. 13 ( 7 ) page： . 2020.7

Effect of Annealing on the Electrical and Optical Properties of MgZnO Films Deposited by Radio Frequency Magnetron Sputtering Reviewed

Kushimoto Maki, Sakai Tadayoshi, Ueoka Yoshihiro, Tomai Shigekazu, Katsumata Satoshi, Deki Manato, Honda Yoshio, Amano Hiroshi

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE Vol. 217 ( 14 ) 2020.7

Halide vapor phase epitaxy of p-type Mg-doped GaN utilizing MgO Reviewed Open Access

Ohnishi Kazuki, Amano Yuki, Fujimoto Naoki, Nitta Shugo, Honda Yoshio, Amano Hiroshi

APPLIED PHYSICS EXPRESS Vol. 13 ( 6 ) page： . 2020.6

Lattice bow in thick, homoepitaxial GaN layers for vertical power devices Open Access

Liu Qiang, Fujimoto Naoki, Shen Jian, Nitta Shugo, Tanaka Atsushi, Honda Yoshio, Sitar Zlatko, Bockowski Michal, Kumagai Yoshinao, Amano Hiroshi

JOURNAL OF CRYSTAL GROWTH Vol. 539 page： . - 125643 2020.6

Impact of high-temperature implantation of Mg ions into GaN Reviewed Open Access

Masahiro Takahashi, Atsushi Tanaka, Yuto Ando, Hirotaka Watanabe, Manato Deki, Maki Kushimoto, Shugo Nitta, Yoshio Honda, Kohei Shima, Kazunobu Kojima, Shigefusa F. Chichibu, Hiroshi Amano

Japanese Journal of Applied Physics Vol. 59 ( 5 ) page： 056502 - 056502 2020.5

Demonstration of Observation of Dislocations in GaN by Novel Birefringence Method

Tanaka Atsushi, Inotsume Syo, Harada Shunta, Hanada Kenji, Honda Yoshio, Ujihara Toru, Amano Hiroshi

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Vol. 257 ( 4 ) 2020.4

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

Herein, a newly developed birefringence microscope is used to observe dislocations in gallium nitride (GaN) substrates. The comparison results of the observation method using this microscope with other observation methods, such as X-ray topography and Raman microscopy, confirms that dislocations in a GaN substrate can be detected with a birefringence microscope. In addition, the observation can be carried out as easily as with an optical microscope. It is also found that under certain observation conditions, the direction of the edge component of dislocations can be determined.

DOI： 10.1002/pssb.201900553

Optimization of InGaN thickness for high-quantum-efficiency Cs/O-activated InGaN photocathode

On-wafer fabrication of etched-mirror UV-C laser diodes with the ALD-deposited DBR Reviewed Open Access

Sakai Tadayoshi, Kushimoto Maki, Zhang Ziyi, Sugiyama Naoharu, Schowalter Leo J, Honda Yoshio, Sasaoka Chiaki, Amano Hiroshi

APPLIED PHYSICS LETTERS Vol. 116 ( 12 ) 2020.3

Indium incorporation and optical properties of polar, semipolar and nonpolar InAlN Reviewed Open Access

Dinh Duc V, Hu Nan, Honda Yoshio, Amano Hiroshi, Pristovsek Markus

SEMICONDUCTOR SCIENCE AND TECHNOLOGY Vol. 35 ( 3 ) 2020.3

Dependence of quantum efficiency on InGaN thickness in InGaN photocathode

Sato Daiki, Honda Anna, Koizumi Atsushi, Nishitani Tomohiro, Honda Yoshio, Amano Hiroshi

JSAP Annual Meetings Extended Abstracts Vol. 2020.1 page： 1516 - 1516 2020.2

Sato Daiki, Honda Anna, Koizumi Atsushi, Nishitani Tomohiro, Honda Yoshio, Amano Hiroshi

MICROELECTRONIC ENGINEERING Vol. 223 2020.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER

The quantum efficiency (QE) of an InGaN photocathode as a function of InGaN layer thickness (240, 100, and 70 nm) was investigated. To activate the sample surface, Cs and O were deposited on the surface in an ultrahigh-vacuum chamber. The QE for different optical power densities was measured by irradiating excitation light from the front and back sides of each sample. The QEs for InGaN layer thickness of 240, 100, and 70 nm with back-side irradiation were 0.9, 9.8, and 7.5%, respectively. For the thicknesses of 70 and 100 nm, the QEs were higher for back-side irradiation than for front-side irradiation, whereas for the thickness of 240 nm, the QE was higher for front-side irradiation. The InGaN layer thickness dependence of the QEs for back- and front-side irradiations was calculated using a continuous equation considering processes such as excitation, diffusion, recombination, and escape of electrons from the surface of the photocathode. The tendency of the experimental results, where QE was maximum at 100-120 nm, corresponded to that of the calculated results.

DOI： 10.1016/j.mee.2020.111229

Analysis of trimethylgallium decomposition by high-resolution mass spectrometry

Ye Zheng, Nitta Shugo, Honda Yoshio, Pristovsek Markus, Amano Hiroshi

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 59 ( 2 ) 2020.2

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

The decomposition of trimethylgallium (Ga(CH3)(3)) was examined under H-2 and N-2 atmospheres using a high-resolution (about 0.002 u) time-of-flight mass spectrometry system, which enabled the separation of N-2 and ethene (C2H4) signals. Under H-2 atmosphere, the main decomposition product was methane (CH4) formed by the hydrogenolysis of Ga(CH3)(3). However, under N-2 atmosphere, the main product is ethane (C2H6) at temperature lower than 660 degrees C. Above 660 degrees C, the C2H6 further decomposes into CH4, acetylene (C2H2) and C2H4, and the main components in the gas phase are C2H2 and C2H4 above 1000 degrees C. Since these are effective carbon dopants, the molar ratio of H-2 to the Ga(CH3)(3) raw material in the carrier gas should be maintained above 300 to inhibit the formation of hydrocarbons in N-2. (C) 2020 The Japan Society of Applied Physics

DOI： 10.35848/1347-4065/ab6fb0

Scalable synthesis of multilayer h-BN on AlN by metalorganic vapor phase epitaxy: nucleation and growth mechanism

Visualization of Different Carrier Concentrations in n-Type GaN Semiconductors by Phase-Shifting Electron Holography with Multiple Electron Biprisms Reviewed Open Access

Kazuo Yamamoto, Kiyotaka Nakano, Atsushi Tanaka, Yoshio Honda, Yuto Ando, Masaya Ogura, Miko Matsumoto, Satoshi Anada, Yukari Ishikawa, Hiroshi Amano, Tsukasa Hirayama

Microscopy Vol. 69 ( 1 ) page： 1 - 10 2020.2

Yang Xu, Nitta Shugo, Pristovsek Markus, Liu Yuhuai, Liao Yaqiang, Kushimoto Maki, Honda Yoshio, Amano Hiroshi

2D MATERIALS Vol. 7 ( 1 ) 2020.1

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

We studied the nucleation and growth of hexagonal BN (h-BN) on AlN template on c-plane sapphire by metalorganic vapor phase epitaxy as functions of growth temperature, deposition time, and triethylboron (TEB) partial pressure. A lateral growth rate of about 25 nm min(-1) for h-BN nuclei was obtained by atomic force microscopy and a nucleation activation energy of 2.1 eV was extracted from the temperature dependence of the nucleation density. A large TEB flow rate strongly enhances the formation of h-BN nuclei. At a reduced TEB flow rate, we observed a significantly decreased nuclei density and a delay in nucleation due to TEB desorption. By fine tuning the growth parameters, single-crystalline multilayer h-BN was successfully formed on AlN surface, as confirmed by x-ray diffraction and transmission electron microscopy (TEM). The epitaxial relationship between h-BN and AlN was [0 0 0 1](h-BN) parallel to [0 0 0 1](AlN) and [1 0 -10](h-BN) parallel to [1 1 -20](AlN) from TEM and electron backscatter diffraction measurements. In addition, TEM showed that the initial h-BN layers are not parallel and tend to form half-domes. On those half-domes (cap-shaped-like) a 2D lateral growth sets on, resulting in a well-oriented 2D multilayer observed in TEM. Thus, the surface topography further develops to form a relatively flat surface without wrinkles and finally a typical hexagon-like wrinkled surface at thicker h-BN layers. Particularly, the small h-BN nuclei have dangling bonds at their periphery that can interact with the substrate, forming actual bonds with AlN. Hence the choice on the substrate is important, despite the basal planes of multilayer h-BN are bonded by a weak van der Waals force.

DOI： 10.1088/2053-1583/ab46e6

Recovery of quantum efficiency on Cs/O-activated GaN and GaAs photocathodes by thermal annealing in vacuum Open Access

Daiki Sato, Tomohiro Nishitani, Yoshio Honda, Hiroshi Amano

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B Vol. 38 ( 1 ) 2020.1

Language：English Publishing type：Research paper (scientific journal) Publisher：A V S AMER INST PHYSICS

In this paper, the authors describe the effectiveness of thermal annealing in vacuum for quantum efficiency (QE) recovery from Cs/O-activated GaN and GaAs photocathodes. The QE of Cs/O-activated GaN photocathodes at 3.4eV dropped from 1.0% to <0.001% upon exposure to nitrogen and then increased to 0.6% upon annealing. On the other hand, the QE of Cs/O-activated GaAs at 1.42eV did not increase after annealing. In addition, after Cs/O activation, the sample was exposed to normal laboratory air and installed in an X-ray photoemission spectroscopy system. Upon annealing at 330<degrees>C, three key results were confirmed as follows: (1) the work function decreased by 0.32eV, (2) the chemical states of Cs 4d and Ga 3d were unchanged, and (3) the intensities of O 1s and C 1s on the high-binding-energy side decreased. In conclusion, the experimental results indicate that the annealing recovers the QE of Cs/O-activated GaN photocathode.

DOI： 10.1116/1.5120417

Characterization of AlGaN multiple-quantum-wells grown on c-plane AlN/sapphire templates with macro-steps

Kojima Kazunobu, Nagasawa Yosuke, Hirano Akira, Ippommatsu Masamichi, Sugie Ryuichi, Honda Yoshio, Amano Hiroshi, Akasaki Isamu, Chichibu Shigefusa F.

Journal of the Japanese Association for Crystal Growth Vol. 47 ( 3 ) page： n/a 2020

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Association for Crystal Growth

The microscopic structural and optical characteristics of AlGaN light-emitting diodes (LEDs) fabricated on the AlN templates with dense macrosteps are shown to clarify the origin of their high internal quantum efficiency of radiation (IQE). The cross-sectional transmission electron microscopy observations under the high-angle annular dark field scanning mode and microscopic energy dispersive X-ray spectroscopy revealed that the AlGaN cladding layer under the AlGaN quantum well (QW) layer had a microscopic compositional modulation, which originates from the macrosteps at the AlN template surface. Moreover, Ga-rich portions in the cladding layer behaved as current micropaths, and the micropaths are connected with the carrier localization structure formed in QWs. The in-plane cathodoluminescence (CL) spectroscopy showed a significant inhomogeneity of the CL characteristics. The gentle slopes at the sample surface showed brighter emissions with a lower peak photon energy, confirming the carrier localization. This carrier localization structure in the QWs combined with the current micropaths in the cladding layer can increase the IQE as well as external quantum efficiency of the AlGaN LEDs.

DOI： 10.19009/jjacg.47-3-04

Dielectric Ruduced Surface Field Effect on Vertical GaN-on-GaN Nanowire Schottky Barrier Diodes

Yaqiang Liao, Tao Chen, Jia Wang, Yuto Ando, Xu Yang, Hirotaka Watanabe, Jun Hirotani, Maki Kushimoto, Manato Deki, Atsushi Tanaka, Shugo Nitta, Yoshio Honda, Kevin J. Chen, Hiroshi Amano

Proceedings of the International Symposium on Power Semiconductor Devices and ICs Vol. 2020-September page： 349 - 352 2020

Language：English Publishing type：Research paper (international conference proceedings)

In this work, gallium nitride (GaN) nanowire (NW) Schottky barrier diodes was fabricated using well-optimized top-down approach. As-fabricated $100 \times 800$-nm-diameter NWs SBD with high current density over 1kA/cm2 at a forward bias of 2.2V, a low differential specific ON-resistance of $0.15\mathrm{m} \Omega \cdot cm^{2}$ are demonstrated. By the virtue of dielectric Reduced Surface Field (RESURF) effect, the device also delivers a breakdown voltage of 515V, leading to a competitive Baliga's Figure of merit of 1.76 GW/cm2.

DOI： 10.1109/ispsd46842.2020.9170101

Untwinned semipolar (10(1)over-bar3) AlxGa1-xN layers grown on m-plane sapphire Reviewed

Dinh Duc V, Hu Nan, Amano Hiroshi, Honda Yoshio, Pristovsek Markus

SEMICONDUCTOR SCIENCE AND TECHNOLOGY Vol. 34 ( 12 ) 2019.12

Suppression of Green Luminescence of Mg-Ion-Implanted GaN by Subsequent Implantation of Fluorine Ions at High Temperature Reviewed

M. Takahashi, A. Tanaka, Y. Ando, H. Watanabe, M. Deki, M. Kushimoto, S. Nitta, Y. Honda, K. Shima, K. Kojima, S. F. Chichibu, K. J. Chen, H. Amano

Physica Status Solidi (b) Vol. 257 page： 1900554 - 1900554 2019.12

Two-dimensional analysis of the nonuniform quantum yields of multiple quantum wells for AlGaN-based deep-ultraviolet LEDs grown on AlN templates with dense macro-steps using cathodoluminescence spectroscopy Reviewed

Y. Nagasawa, R. Sugie, K. Kojima, A. Hirano, M. Ipponmatsu, Y. Honda, H. Amano, I. Akasaki, S. F. Chichibu

Journal of Applied Physics Vol. 126 ( 21 ) page： 215703 1 - 10 2019.12

Low Voltage High-Energy α-Particle Detectors by GaN-on-GaN Schottky Diodes with Record-High Charge Collection Efficiency. Reviewed Open Access

Sandupatla A, Arulkumaran S, Ranjan K, Ng GI, Murmu PP, Kennedy J, Nitta S, Honda Y, Deki M, Amano H

Sensors (Basel, Switzerland) Vol. 19 ( 23 ) 2019.11

Aluminium incorporation in polar, semi- and non-polar AlGaN layers: a comparative study of x-ray diffraction and optical properties Reviewed Open Access

Duc V Dinh, Hu Nan, Honda Yoshio, Amano Hiroshi, Pristovsek Markus

SCIENTIFIC REPORTS Vol. 9 ( 1 ) page： 15802 2019.11

V-shaped dislocations in a GaN epitaxial layer on GaN substrate Open Access

Tanaka Atsushi, Nagamatsu Kentaro, Usami Shigeyoshi, Kushimoto Maki, Deki Manato, Nitta Shugo, Honda Yoshio, Bockowski Michal, Amano Hiroshi

AIP ADVANCES Vol. 9 ( 9 ) 2019.9

Language：English Publishing type：Research paper (scientific journal)

In this study, V-shaped dislocations in a GaN epitaxial layer on a free-standing GaN substrate were observed. Our investigation further revealed that the V-shaped dislocations were newly generated at the interface in the epilayer rather than propagated from the GaN substrate. V-shaped dislocations consist of two straight parts. The straight parts of the V-shaped dislocations were separated from each other in the m-direction and tilted toward the step-flow direction of the GaN epitaxial layer. The V-shaped dislocations are continuous single dislocations having a Burgers vector component of 1a and an intrinsic stacking fault between their straight parts.

DOI： 10.1063/1.5114866

Precise Measurement of Carrier Concentrations in n-Type GaN by Phase-Shifting Electron Holography

Kazuo Yamamoto, Kiyotaka Nakano, Atsushi Tanaka, Yoshio Honda, Yuto Ando, Masaya Ogura, Miko Matsumoto, Satoshi Anada, Yukari Ishikawa, Hiroshi Amano, Tsukasa Hirayama

Microscopy and Microanalysis Vol. 25 ( S2 ) page： 50 - 51 2019.8

Origin of acceptor diffusion into silicon substrate during GaN growth by metal organic chemical vapor deposition Reviewed Open Access

Matsumoto Koji, Ono Toshiaki, Honda Yoshio, Torigoe Kazuhisa, Kushimoto Maki, Amano Hiroshi

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 58 ( 7 ) 2019.7

Ammonia decomposition and reaction by high-resolution mass spectrometry for group III - Nitride epitaxial growth Open Access

Ye Zheng, Nitta Shugo, Nagamatsu Kentaro, Fujimoto Naoki, Kushimoto Maki, Deki Manato, Tanaka Atsushi, Honda Yoshio, Pristovsek Markus, Amano Hiroshi

JOURNAL OF CRYSTAL GROWTH Vol. 516 page： 63 - 66 2019.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The decomposition of ammonia (NH3) in nitrogen (N-2) ambient was studied under non-equilibrium conditions similar to those in a metal organic vapor phase epitaxy (MOVPE) reactor during the epitaxial growth of group-III nitrides. The gas phase was sampled at different positions and analyzed using a time-of-flight mass spectrometry system with a high resolution (better than 0.002 u). Our results expand earlier findings. Even at the high temperature of 1200 degrees C, only 26% of NH3 decomposed in a clean metal-free reactor, whereas a higher ratio of NH3 decomposition was realized in the presence of stainless steel. The activation energy in the clean reactor was calculated to be 0.965 +/- 0.004 eV. These results demonstrate the capability of our setup and shed new light on the elucidation of the vapor phase growth mechanism of group III-nitrides by MOVPE.

DOI： 10.1016/j.jcrysgro.2019.03.025

Direct evidence of Mg diffusion through threading mixed dislocations in GaN p-n diodes and its effect on reverse leakage current Reviewed International journal

Shigeyoshi Usami, Norihito Mayama, Kazuya Toda, Atsushi Tanaka, Manato Deki, Shugo Nitta, Yoshio Honda, Hiroshi Amano

APPLIED PHYSICS LETTERS Vol. 114 ( 23 ) 2019.6

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

Mg diffusion is a common problem in GaN devices with p-n junctions. Although this impurity diffusion is reported to occur through threading dislocations (TDs), no direct evidence has yet been obtained. Therefore, we tried the direct observation of Mg diffusion by atom probe tomography (APT) analysis. The n-type drift layer of the fabricated p-n diode was exposed, and etch pits were formed on the drift layer to identify the TD position. The APT analysis around TDs was carried out by lifting out the drift layer around specific etch pits using a focused ion beam to include TDs. The relationship between the etch pit shape and the TD type was confirmed by cross-sectional scanning transmission electron microscopy observation. The APT analysis of two types of etch pits formed on the mixed dislocations was performed, and Mg diffusion was clearly observed through the mixed dislocations. In this work, we show direct evidence of Mg diffusion via mixed dislocations in GaN p-n diodes and its effect on reverse leakage current.

DOI： 10.1063/1.5097767

Computational fluid dynamics simulation study of the gas flow balance in a vertical HVPE reactor with a showerhead for low cost bulk GaN crystal growth Reviewed

Liu Qiang, Fujimoto Naoki, Nitta Shugo, Honda Yoshio, Amano Hiroshi

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 58 2019.6

Frontiers of Nitride Semiconductor Research FOREWORD

Chichibu Shigefusa F, Kumagai Yoshinao, Kojima Kazunobu, Deura Momoko, Akiyama Toru, Arita Munetaka, Fujioka Hiroshi, Fujiwara Yasufumi, Hara Naoki, Hashizume Tamotsu, Hirayama Hideki, Holmes Mark, Honda Yoshio, Imura Masataka, Ishii Ryota, Ishitani Yoshihiro, Iwaya Motoaki, Kamiyama Satoshi, Kangawa Yoshihiro, Katayama Ryuji, Kawakami Yoichi, Kawamura Takahiro, Kobayashi Atsushi, Kuzuhara Masaaki, Matsumoto Koh, Mori Yusuke, Mukai Takashi, Murakami Hisashi, Murotani Hideaki, Nakazawa Satoshi

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 58 2019.6

Effect of photoelectrochemical etching and post-metallization annealing on gate controllability of AlGaN/GaN high electron mobility transistors Reviewed International journal Open Access

Keisuke Uemura, Manato Deki, Yoshio Honda, Hiroshi Amano, Taketomo Sato

Japanese Journal of Applied Physics Vol. 58 ( SC ) page： SCCD20-1 - SCCD20-6 2019.6

Deeply and vertically etched butte structure of vertical GaN p-n diode with avalanche capability Reviewed International journal

Hayata Fukushima, Shigeyoshi Usami, Masaya Ogura, Yuto Ando, Atsushi Tanaka, Manato Deki, Maki Kushimoto, Shugo Nitta, Yoshio Honda, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 58 2019.6

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

A vertical p-n diode with a simple edge termination structure on a GaN free-standing substrate is demonstrated. The edge of this device is terminated simply by etching a drift layer deeply and vertically. A device simulation revealed that the electric field at the device edge was more relaxed and uniformly applied by etching the mesa deeper than the depletion region. The fabricated device showed low leakage current and avalanche capability, and its breakdown characteristics could be reproduced many times. By emission microscopy observation, we found that there was no leakage current at the side wall of the device and that avalanche breakdown occurred throughout the inside of the device. This indicates that the electric field crowding at the side wall of the device was completely suppressed and a uniform electric field distribution was obtained by this structure. (C) 2019 The Japan Society of Applied Physics

DOI： 10.7567/1347-4065/ab106c

Correlation between nanopipes formed from screw dislocations during homoepitaxial growth by metal-organic vapor-phase epitaxy and reverse leakage current in vertical p-n diodes on a free-standing GaN substrates Reviewed International journal Open Access

Shigeyoshi Usami, Atsushi Tanaka, Hayata Fukushima, Yuto Ando, Manato Deki, Shugo Nitta, Yoshio Honda, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 58 2019.6

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

We fabricated p-n diodes under different growth pressures on free-standing GaN substrates of the same quality and observed a noteworthy difference in the reverse leakage current. A large reverse leakage current was generated by nanopipes, which were formed from screw dislocations in the homoepitaxial layer. There were two types of screw dislocation observed in this study. The first type already existed in the substrate and the other was newly generated in the epilayer by the coalescence of edge and mixed dislocations. An increase in the growth pressure suppressed the transformation of screw dislocations into nanopipes, which led to a reduction in the reverse leakage current. To reduce the leakage current further, it is necessary to apply growth conditions that do not transform screw dislocation into nanopipes and to use a free-standing substrate without threading dislocations, that become nanopipes. (C) 2019 The Japan Society of Applied Physics

DOI： 10.7567/1347-4065/ab1250

Controlling the orientations of directional sputtered non- and semi-polar GaN/AlN layers Reviewed

Nan Hu, Dinh Duc V, Pristovsek Markus, Honda Yoshio, Amano Hiroshi

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 58 2019.6

Comparison of AlxGa1-xN multiple quantum wells designed for 265 and 285nm deep-ultraviolet LEDs grown on AlN templates having macrosteps Reviewed

Nagasawa Yosuke, Kojima Kazunobu, Hirano Akira, Ipponmatsu Masamichi, Honda Yoshio, Amano Hiroshi, Akasaki Isamu, Chichibu Shigefusa F

APPLIED PHYSICS EXPRESS Vol. 12 ( 6 ) 2019.6

Morphological study of InGaN on GaN substrate by supersaturation (vol 508, pg 58, 2019) Reviewed

Liu Zhibin, Nitta Shugo, Robin Yoann, Kushimoto Maki, Deki Manato, Honda Yoshio, Pristovsek Markus, Sitar Zlatko, Amano Hiroshi

JOURNAL OF CRYSTAL GROWTH Vol. 514 page： 13 - 13 2019.5

Effect of substrate misorientation on the concentration of impurities and surface morphology of an epitaxial GaN layer on N-polar GaN substrate by MOVPE Open Access

Nagamatsu Kentaro, Ando Yuto, Kono Tsukasa, Cheong Heajeong, Nitta Shugo, Honda Yoshio, Pristovsek Markus, Amano Hiroshi

JOURNAL OF CRYSTAL GROWTH Vol. 512 page： 78 - 83 2019.4

Language：English Publishing type：Research paper (scientific journal)

This study examines the effect of (0 0 0 −1) GaN substrate misorientation on the residual impurities and surface morphology of N-polar GaN grown by metalorganic vapor-phase epitaxy. Carbon, silicon, and oxygen concentrations decreased with increasing GaN substrate misorientation angle, with the lowest impurity concentration achieved for a misorientation angle of 2° toward the m-axis, with 6 × 10 15 cm −3 carbon, 6 × 10 15 cm −3 silicon, and 4 × 10 17 cm −3 oxygen atoms. The oxygen concentration was measured at a depth of 0.5 μm below the wafer surface, and the oxygen concentration decreased with increasing thickness. The incorporation of carbon and oxygen revealed a strong dependence on the misorientation angle. The step distance height of the steps parallel to the [1 1 −2 0] direction (or perpendicular to the [1 −1 0 0] m-direction) was confirmed to be a double-height layer step. This phenomenon indicated that m-direction steps are stable for N-polar growth in GaN. In cases of large misorientation toward the m-axis in of the GaN substrate it was difficult to control the misorientation perpendicular to the nominal direction leading to a-axis direction by wafer bowing at wafer manufacturing. Therefore, step-bunching was generated for each symmetric m-axis due to an increase in the compound's off-angle, thus causing the surface roughness to become large.

DOI： 10.1016/j.jcrysgro.2019.02.013

Transfer-free fabrication of a graphene transparent electrode on a GaN-based light-emitting diode using the direct precipitation method Reviewed

Yamada Jumpei, Usami Shigeyoshi, Ueda Yuki, Honda Yoshio, Amano Hiroshi, Maruyama Takahiro, Naritsuka Shigeya

Jpn. J. Appl. Phys. Vol. 58 ( 4 ) 2019.3

Effect of gas phase temperature on InGaN grown by metalorganic vapor phase epitaxy Open Access

Zhibin Liu, Shugo Nitta, Shigeyoshi Usami, Yoann Robin, Maki Kushimoto, Manato Deki, Yoshio Honda, Markus Pristovsek, Hiroshi Amano

JOURNAL OF CRYSTAL GROWTH Vol. 509 page： 50 - 53 2019.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Wafer trays with different gaps (the distance between the top of the pocket and the bottom of the wafer) were used to grow InGaN/GaN multiple quantum wells (MQWs) in a horizontal metalorganic vapor phase epitaxy (MOVPE) reactor. The numerical reactor simulation revealed that at the similar surface temperature the gas phase temperature around the wafer increases due to an increased wafer tray temperature. This increased gas phase temperature is expected to increase the effective V/III ratio by enhanced NH3 decomposition. Photoluminescence (PL) intensities of long-wavelength MQWs increased at the same indium content by the enhanced gas phase temperature, while the emission became narrow. This is related to a smoother topography at higher gas phase temperatures.

DOI： 10.1016/j.jcrysgro.2018.12.007

Fully Ion Implanted Normally-Off GaN DMOSFETs with ALD-Al2O3 Gate Dielectrics Reviewed Open Access

Yoshino Michitaka, Ando Yuto, Deki Manato, Toyabe Toru, Kuriyama Kazuo, Honda Yoshio, Nishimura Tomoaki, Amano Hiroshi, Kachi Tetsu, Nakamura Tohru

MATERIALS Vol. 12 ( 5 ) 2019.3

The annealing effect for the N2-exposed surface of the semiconductor photocathode

Sato Daiki, NIshitani Tomohiro, Honda Yoshio, Amano Hiroshi

JSAP Annual Meetings Extended Abstracts Vol. 2019.1 page： 1474 - 1474 2019.2

Morphological study of InGaN on GaN substrate by supersaturation Reviewed Open Access

Liu Zhibin, Nitta Shugo, Robin Yoann, Kushimoto Maki, Deki Manato, Honda Yoshio, Pristovsek Markus, Amano Hiroshi

JOURNAL OF CRYSTAL GROWTH Vol. 508 page： 58 - 65 2019.2

How to obtain metal-polar untwinned high-quality (10-13) GaN on m-plane sapphire Reviewed Open Access

Hu Nan, Dinh Duc V, Pristovsek Markus, Honda Yoshio, Amano Hiroshi

JOURNAL OF CRYSTAL GROWTH Vol. 507 page： 205 - 208 2019.2

Vertical GaN p-n diode with deeply etched mesa and the capability of avalanche breakdown Open Access

Hayata Fukushima, Shigeyoshi Usami, Masaya Ogura, Yuto Ando, Atsushi Tanaka, Manato Deki, Maki Kushimoto, Shugo Nitta, Yoshio Honda, Hiroshi Amano

APPLIED PHYSICS EXPRESS Vol. 12 ( 2 ) 2019.2

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

A simple structure with high breakdown voltage and a low leakage current of a vertical GaN p-n diode on a GaN free-standing substrate is demonstrated. We describe a vertical p-n diode with a simple edge termination that has a drift layer etched deeply and vertically. A device simulation revealed that the electric field was more relaxed at the device edge and applied uniformly in the entire device with increasing etching depth. We fabricated the simulated structure and succeeded in reducing the leakage current and improving the breakdown voltage. With this structure, a stable avalanche breakdown can be observed. (C) 2019 The Japan Society of Applied Physics

DOI： 10.7567/1882-0786/aafdb9

Observation of Dopant Concentration in GaN Semiconductor by High Sensitivity Electron Holography Reviewed

Carrier localization structure combined with current micropaths in AlGaN quantum wells grown on an AIN template with macrosteps Reviewed

Kojima K, Nagasawa Y, Hirano A, Ippommatsu M, Honda Y, Amano H, Akasaki I, Chichibu S. F

APPLIED PHYSICS LETTERS Vol. 114 ( 1 ) 2019.1

Nakano Kiyotaka, Honda Yoshio, Amano Hiroshi, Matsumoto Miko, Anada Satoshi, Yamamoto Kazuo, Ishikawa Yukari, Hirayama Tsukasa, Ando Yuto, Ogura Masaya, Tanaka Atsushi

Materia Japan Vol. 58 ( 2 ) page： 103-103 - 103 2019

Electronic structure analysis of core structures of threading dislocations in GaN Reviewed

Takashi Nakano, Kenta Chokawa, Masaaki Araidai, Kenji Shiraishi, Atsushi Oshiyama, Akira Kusaba, Yoshihiro Kangawa, Atsushi Tanaka, Yoshio Honda, Hiroshi Amano

2019 Compound Semiconductor Week, CSW 2019 - Proceedings page： . 2019

Language：English Publishing type：Research paper (international conference proceedings)

© 2019 IEEE. It is known that threading dislocations degrade the performance of GaN-based electronic devices. Electronic structure of threading dislocations in GaN is not fully understood. Accordingly, we examine the electronic structures of threading dislocations in GaN using first principles calculations based on density functional theory (DFT) and to clarify the origin of the leakage current. We have comprehensively studied the relation between threading core structures and electronic property in GaN thin films. Our calculation models of threading dislocations are the edge dislocations with Burgers vectors of 1/3 [11-20] and the screw dislocations with Burgers vectors of [0001]. We examined various core types of the threading dislocations. We found that both edge dislocations and screw dislocations do not cause the leakage currents in n-type GaN based devices because no defect level appears near the conduction band bottom.

DOI： 10.1109/iciprm.2019.8819270

Analysis of negative electron affinity InGaN photocathode by temperature-programed desorption method

Kashima Masahiro, Sato Daiki, Koizumi Atsushi, Nishitani Tomohiro, Honda Yoshio, Amano Hiroshi, Iijima Hokuto, Meguro Takashi

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B Vol. 36 ( 6 ) 2018.11

Language：English Publishing type：Research paper (scientific journal) Publisher：A V S AMER INST PHYSICS

A III-V semiconductor with a few monolayers of alkali metals (e.g., Cs) forms a negative electron affinity (NEA) surface, for which the vacuum level lies below the conduction band minimum of the base semiconductor. The photocathodes that form an NEA surface (NEA photocathodes) have various advantages, such as low emittance, a large current, high spin polarization, and ultrashort pulsed operation. The NEA-InGaN photocathode, which is sensitive to blue light, has been studied as a material for the next-generation robust photocathode. However, the proper conditions for forming NEA surfaces remain unknown. The authors consider whether the suitable process for NEA surfaces can be understood by investigating the relationship between the electron emission and the adsorption state of alkali metals. In this study, the relationship between the electron emission and the adsorption state of Cs on the p-type InGaN (0001) was analyzed by the temperature programed desorption (TPD) method using a quadrupole mass spectrometer. From the results of the TPD measurements, it was shown that there were several adsorption states of Cs on InGaN. The quantum efficiency (QE), which indicates the ratio of emitted electrons to incident photons, increased while Cs desorption occurred. The authors divided the formation process of an NEA surface into several sections to investigate the adsorption states of Cs related to the electron emission and to discuss the reasons why the QE increased despite the desorbed Cs. From the results of the NEA activation in each section, it was shown that there were sections where the QE increased by reacting with O-2 after Cs supply stopped. There is a possibility that several layers reacting with O-2 and those not reacting with O-2 are formed by performing NEA activation until the QE saturates. From the results of the TPD measurements in each section, it was suggested that there was a Cs peak at above 700 degrees C when the TPD method was carried out immediately after confirming the electron emission. Therefore, the adsorption state of Cs that formed a peak at above 700 degrees C had a close relation to the electron emission. It is considered that the increase of the QE in the TPD was affected by adsorbed Cs compounds that reacted with O-2. Although the mechanism is not understood, it is known that the QE was increased by the reaction of Cs adsorbed compounds and O-2 in previous studies. It was suspected that layers that reacted with O-2 appeared from TPD and then the QE increased by reacting with O-2. Published by the AVS.

DOI： 10.1116/1.5048061

Reduction of Residual Impurities in Homoepitaxial m-Plane (10(1)over-bar0) GaN by Using N-2 Carrier Gas in Metalorganic Vapor Phase Epitaxy Reviewed

Comparing high-purity c- and m-plane GaN layers for Schottky barrier diodes grown homoepitaxially by metalorganic vapor phase epitaxy Reviewed

Vol. 57 ( 10 ) 2018.10

High-temperature thermal annealing of nonpolar (10(1)over-bar0) AlN layers sputtered on (1 0(1)over-bar0) sapphire Reviewed Open Access

Dinh Duc V, Hu Nan, Honda Yoshio, Amano Hiroshi, Pristovsek Markus

JOURNAL OF CRYSTAL GROWTH Vol. 498 page： 377 - 380 2018.9

The annealing effect for the air-exposed surface on the GaN semiconductor photocathode

Sato Daiki, Nishitani Tomohiro, Honda Yoshio, Amano Hiroshi

JSAP Annual Meetings Extended Abstracts Vol. 2018.2 page： 1571 - 1571 2018.9

Detailed study of effects of duration of pre-AIN-growth trimethylaluminum step on morphologies of GaN layers grown on silicon substrate by metal organic chemical vapor deposition Reviewed

Vol. 57 ( 9 ) 2018.9

Barry Ousmane I, Lekhal Kaddour, Bae Si-Young, Lee Ho-Jun, Pristovsek Markus, Honda Yoshio, Amano Hiroshi

PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS Vol. 12 ( 8 ) 2018.8

Raman Spectroscopic Study of GaN Grown on (111)Si Using an AlInN Intermediate Layer by MOVPE Reviewed

T.Sugiura, S.Kawasaki, Y.Honda, T.Nonaka, D.Oikawa, T.Tsukamoto, H.Andoh, H.Amano

Book of abstracts ISGN-7(7th International Symposium on Growth of IIINitrides) page： Po01 2018.8

Improvement of breakdown voltage of vertical GaN p-n junction diode with Ga2O3 passivated by sputtering Reviewed

Ueoka Yoshihiro, Deki Meneto, Honda Yoshio, Amano Hiroshi

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 57 ( 7 ) 2018.7

Study on the Main-Chain Structure of Amorphous Fluorine Resins for Encapsulating AlGaN-Based DUV-LEDs

Kiho Yamada, Yosuke Nagasawa, Shoko Nagai, Akira Hirano, Masamichi Ippommatsu, Ko Aosaki, Yoshio Honda, Hiroshi Amano, Isamu Akasaki

Physica Status Solidi (A) Applications and Materials Science Vol. 215 ( 10 ) 2018.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Verlag

The main chain structure of optically isotropic amorphous fluorine resin for encapsulating AlGaN-based deep-ultraviolet LEDs (λ &lt
300 nm) is studied. One type of amorphous fluorine resin has a five-membered ring with a single oxygen atom and the other has that one with two oxygen atoms. Reliability testing is performed using AlGaN-based LEDs of 262 and 289 nm. For the resin with two oxygen atoms in the ring, visible damage to the electrode and significantly increased leakage current are considered to been caused by the photolysis of the ring induced by irradiation with deep-ultraviolet light. In contrast, electrode damage and increased leakage are not observed in the case of the resin with the single-oxygen ring.

DOI： 10.1002/pssa.201700525

m-Plane GaN Schottky Barrier Diodes Fabricated With MOVPE Layer on Several Off-Angle m-Plane GaN Substrates Open Access

Atsushi Tanaka, Yuto Ando, Kentaro Nagamatsu, Manato Deki, Heajeong Cheong, Barry Ousmane, Maki Kushimoto, Shugo Nitta, Yoshio Honda, Hiroshi Amano

Physica Status Solidi (A) Applications and Materials Science Vol. 215 ( 9 ) 2018.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Verlag

In this study, GaN m-plane Schottky barrier diodes are fabricated by metalorganic vapor-phase epitaxy (MOVPE) on several off-angle gallium nitride (GaN) substrates, and the off-cut angle dependence of impurity incorporation is investigated. We show that the MOVPE layer on the substrate inclined 5° toward the [000–1] direction has extremely low impurity incorporation. These results provide important suggestions for the fabrication of m-plane power devices.

DOI： 10.1002/pssa.201700645

Interface amorphization in hexagonal boron nitride films on sapphire substrate grown by metalorganic vapor phase epitaxy Reviewed Open Access

Vol. 11 ( 5 ) 2018.5

Reduction of Dislocations in GaN on Silicon Substrate Using In Situ Etching Open Access

Koji Matsumoto, Toshiaki Ono, Yoshio Honda, Tetsuya Yamamoto, Shigeyoshi Usami, Maki Kushimoto, Satoshi Murakami, Hiroshi Amano

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Vol. 255 ( 5 ) 2018.5

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

A gallium nitride (GaN) epitaxial layer with a low density of threading dislocations is successfully grown on a silicon substrate by using in situ gas etching. Silicon nitride (SiNx) film is used as a mask, and ammonia is intermittently supplied in hydrogen ambient during the etching. After etching, high-density deep pits appeared on the surface of a GaN template layer and corresponded to the threading dislocations in the layer. In this novel method, before growing an additional GaN layer on the template GaN layer, a second SiNx layer is deposited after the etching process, and this layer prevents GaN nuclei from growing on the upper side-walls of the pits. By using this method, the density of threading dislocations of the GaN surface is reduced to 6.7x10(7)cm(-2). This method is cost effective, completing all the necessary processes in one growth run without taking samples out from a metalorganic chemical vapor deposition (MOCVD) reactor.

DOI： 10.1002/pssb.201700387

Correlation between dislocations and leakage current of p-n diodes on a free-standing GaN substrate

Shigeyoshi Usami, Yuto Ando, Atsushi Tanaka, Kentaro Nagamatsu, Manato Deki, Maki Kushimoto, Shugo Nitta, Yoshio Honda, Hiroshi Amano, Yoshihiro Sugawara, Yong-Zhao Yao, Yukari Ishikawa

APPLIED PHYSICS LETTERS Vol. 112 ( 18 ) 2018.4

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

Dislocations that cause a reverse leakage current in vertical p-n diodes on a GaN free-standing substrate were investigated. Under a high reverse bias, dot-like leakage spots were observed using an emission microscope. Subsequent cathodoluminescence (CL) observations revealed that the leakage spots coincided with part of the CL dark spots, indicating that some types of dislocation cause reverse leakage. When etch pits were formed on the dislocations by KOH etching, three sizes of etch pits were obtained (large, medium, and small). Among these etch pits, only the medium pits coincided with leakage spots. Additionally, transmission electron microscopy observations revealed that pure screw dislocations are present under the leakage spots. The results revealed that lc pure screw dislocations are related to the reverse leakage in vertical p-n diodes. Published by AIP Publishing.

DOI： 10.1063/1.5024704

Growth of hexagonal boron nitride on sapphire substrate by pulsed-mode metalorganic vapor phase epitaxy International journal Open Access

Xu Yang, Shugo Nitta, Kentaro Nagamatsu, Si-Young Bae, Ho-Jun Lee, Yuhuai Liu, Markus Pristovsek, Yoshio Honda, Hiroshi Amano

JOURNAL OF CRYSTAL GROWTH Vol. 482 page： 1 - 8 2018.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Hexagonal boron nitride (h-BN) was directly grown on sapphire substrate using alternating ammonia (NH3) and triethylboron (TEB) supply (pulsed mode) in metalorganic vapor phase epitaxy. The best condition is when just enough NH3 is supplied to fully convert the TEB within one cycle. Excess NH3 caused islands on h-BN film surface while a lack of NH3 does not form h-BN at all. The epitaxial relationship between grown h-BN layer and c-plane sapphire was confirmed to be [0001](h-BN)||[0001](sapphire) and [10-10](h-BN)||[11-20](sapphire). It is known that, compared to AlN, BN requires higher V/III ratios for good crystallinity, which due to severe gas-phase reactions is difficult to achieve using continuous supply. Thus using pulsed mode the FWHM of the symmetric (0002) diffraction was almost halved and the growth rate was several times faster. (C) 2017 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jcrysgro.2017.10.036

Theoretical Study of the Electronic Structure of Threading Edge Dislocations in GaN Reviewed

Nakano Takashi, Araidai Masaaki, Shiraishi Kenji, Tanaka Atsushi, Honda Yoshio, Amano Hiroshi

GALLIUM NITRIDE AND SILICON CARBIDE POWER TECHNOLOGIES 8 Vol. 86 ( 12 ) page： 41 - 49 2018

Electrical and Thermal Analysis of Vertical GaN-on-GaN PN Diodes Reviewed

Yates Luke, Pavlidis Georges, Graham Samuel, Usami Shigeyoshi, Nagamatsu Kentaro, Honda Yoshio, Amano Hiroshi

PROCEEDINGS OF THE 17TH IEEE INTERSOCIETY CONFERENCE ON THERMAL AND THERMOMECHANICAL PHENOMENA IN ELECTRONIC SYSTEMS (ITHERM 2018) page： 831-837 2018

Charge-to-time converting leading-edge discriminator for plastic-scintillator signals International journal

T. Ishikawa, Y. Takeda, Y. Honda, Y. Inoue, H. Kanda, S. Kido, Y. Matsumura, M. Miyabe, I. Nagasawa, H. Shimizu, T. Takeda, A. O. Tokiyasu, Y. Tsuchikawa, H. Yamazaki

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 875 page： 193 - 200 2017.12

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We have developed a charge-to-time converting (QTC) leading-edge discriminator for plastic-scintillator signals, which is packaged in a NIM-standard double-width module. The pulse width of the discriminator output is approximately proportional to the charge integration of input signals up to 40-50 pC. The non-linearity is 20%, 10%, 4%, and 2% at maximum for the input charges below 7 pC, for 7-10 pC, for 10-20 pC, and above 20 pC, respectively, for the minimum input charges larger than 2 pC. The discriminator could be suitable in the measurement of the timing and charge of plastic-scintillator signals together with a multi-hit time-to-digital converter (TDC) module. (C) 2017 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nima.2017.09.040

Initial leakage current paths in the vertical-type GaN-on-GaN Schottky barrier diodes International journal

Liwen Sang, Bing Ren, Masatomo Sumiya, Meiyong Liao, Yasuo Koide, Atsushi Tanaka, Yujin Cho, Yoshitomo Harada, Toshihide Nabatame, Takashi Sekiguchi, Shigeyoshi Usami, Yoshio Honda, Hiroshi Amano

APPLIED PHYSICS LETTERS Vol. 111 ( 12 ) 2017.9

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

Electrical characteristics of leakage current paths in vertical-type n-GaN Schottky barrier diodes (SBDs) on free-standing GaN substrates are investigated by using photon emission microscopy (PEM). The PEM mapping shows that the initial failure of the SBD devices at low voltages is due to the leakage current paths from polygonal pits in the GaN epilayers. It is observed that these polygonal pits originate from carbon impurity accumulation to the dislocations with a screw-type component by microstructure analysis. For the SBD without polygonal pits, no initial failure is observed and the first leakage appeals at the edge of electrodes as a result of electric field concentration. The mechanism of leakage at pits is explained in terms of trap assisted tunneling through fitting current-voltage characteristics.

DOI： 10.1063/1.4994627

Absolute technique for measuring internal electric fields in InGaN/GaN light-emitting diodes by electroreflectance applicable to all crystal orientations International journal

Tomoyuki Tanikawa, Kanako Shojiki, Ryuji Katayama, Shigeyuki Kuboya, Takashi Matsuoka, Yoshio Honda, Hiroshi Amano

APPLIED PHYSICS EXPRESS Vol. 10 ( 8 ) 2017.8

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

The internal electric fields in III-polar (0001), N-polar (0001), and semipolar (1011) InGaN/GaN light-emitting diodes were investigated by electroreflectance (ER) spectroscopy. The ER spectra reflected the difference in the direction and strength of internal electric fields. Phase analyses of the ER signal revealed that only III-polar InGaN wells have the opposite direction of the internal electric field at zero bias voltage; this finding is in good agreement with the results of numerical analyses. Quantitative analyses of internal electric fields were conducted by the linewidth analyses of ER spectra. Our experimental results indicate that the absolute value of internal electric fields can be measured from ER spectra. (C) 2017 The Japan Society of Applied Physics

DOI： 10.7567/APEX.10.082101

Selective-area growth of doped GaN nanorods by pulsed-mode MOCVD: Effect of Si and Mg dopants

Si-Young Bae, Kaddour Lekhal, Ho-Jun Lee, Jung-Wook Min, Dong-Seon Lee, Yoshio Honda, Hiroshi Amano

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Vol. 254 ( 8 ) 2017.8

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

Injecting current with a uniform carrier concentration is important for applications with three-dimensional architectures such as vertical power devices or displays. In III-nitride nanostructures, dopants not only incorporate differently depending on the surface orientation but can also seriously affect the kinetic equilibrium shapes of the nanorods. Herein, we report selective-area growth of doped GaN nanorods grown by pulsed-mode metalorganic chemical vapor deposition. Two dopants, Si and Mg, were employed as donor and acceptor atoms, respectively, for a mono-doping approach. Furthermore, a mixed flow of Si and Mg was supplied for a co-doping approach. We compared the morphological effects and growth rates of each doped GaN nanorod array. Then, we proposed appropriate growth mechanisms for the doped GaN nanorods on the basis of our structural characterizations. These results might extend the morphological functionality of GaN nanorods by including doping and may also provide an appropriate foundation for the design of nanostructure-based electronic or photonic devices. (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

DOI： 10.1002/pssb.201600722

Facet dependence of leakage current and carrier concentration in m-plane GaN Schottky barrier diode fabricated with MOVPE International journal

Atsushi Tanaka, Ousmane Barry, Kentaro Nagamatsu, Junya Matsushita, Manato Deki, Yuto Ando, Maki Kushimoto, Shugo Nitta, Yoshio Honda, Hiroshi Amano

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE Vol. 214 ( 8 ) 2017.8

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

In this study, GaN m-plane Schottky barrier diodes fabricated with a metalorganic vapor-phase epitaxy on a GaN substrate were investigated using emission microscope, photoluminescence, and cathodoluminescence. In addition, facet dependence of leakage current under reverse-biased condition was observed. We showed that the leakage-current distribution was caused by the facet dependence of the carrier concentration and oxygen concentration. These results can provide important suggestions for the fabrication of m-plane devices. (a) four-faceted hillocks on m-plane GaN MOVPE sample, facet dependence of (b) leakage current and (c) PL peak intensity of the m-plane GaN Schottky barrier diode.

DOI： 10.1002/pssa.201600829

Effect of dislocations on the growth of p-type GaN and on the characteristics of p-n diodes International journal

Shigeyoshi Usami, Ryosuke Miyagoshi, Atsushi Tanaka, Kentaro Nagamatsu, Maki Kushimoto, Manato Deki, Shugo Nitta, Yoshio Honda, Hiroshi Amano

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE Vol. 214 ( 8 ) 2017.8

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

We investigate the influence of crystal defects on p-type GaN grown by metalorganic vapor phase epitaxy. Sets of p-type GaN films were grown on sapphire substrates and on free-standing GaN (F-GaN) substrates simultaneously using various Et-Cp2Mg flow rates. Although there is a difference of two orders of magnitude between the threading dislocation densities of p-type GaN grown on sapphire and F-GaN substrates, there is no significant difference in hole concentration. However, there are problems with the surface morphology of p-type GaN grown on sapphire. The deterioration of the surface was caused by the difference in nanopipe density. The electrical properties of a p-n junction diode formed on sapphire with a high density of nanopipes were observed using emission microscopy under both forward- and reverse-bias conditions. Our results demonstrate that the nanopipes are electrically inactive, and that other types of threading dislocation have more influence on the current-voltage characteristics.

DOI： 10.1002/pssa.201600837

Decomposition of trimethylgallium and adduct formation in a metalorganic vapor phase epitaxy reactor analyzed by high-resolution gas monitoring system International journal

Kentaro Nagamatsu, Shugo Nitta, Zheng Ye, Hirofumi Nagao, Shinichi Miki, Yoshio Honda, Hiroshi Amano

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Vol. 254 ( 8 ) 2017.8

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

In this study, by using time-of-flight (TOF) high-resolution and high-sensitivity mass spectrometry measurements, the decomposition of trimethylgallium into dimethylgallium and monomethylgallium along with its adduct formation with NHx in a commercially available horizontal metalorganic vapor-phase epitaxy (MOVPE) reactor with a resistive heater was investigated and observed in more detail than previously reported. The results confirmed the use of the TOF monitoring system in analyzing the elementary reaction process in actual MOVPE systems. (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

DOI： 10.1002/pssb.201600737

A-plane GaN growth on (11-20) 4H-SiC substrate with an ultrathin interlayer International journal

Zheng Sun, Peifeng Song, Shugo Nitta, Yoshio Honda, Hiroshi Amano

JOURNAL OF CRYSTAL GROWTH Vol. 468 page： 866 - 869 2017.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

A-plane GaN was attempted to be grown on (11-20) 4H-SiC bulk substrate without using a traditional thick buffer layer. By inducing TMAl treatment before the GaN growth step and using both a low pressure and V/III ratio, the interlayer thickness of the a-plane GaN/SiC was reduced to 1.7 +/- 0.5 nm. The ultrathin interlayer was observed to be either AlN or AlGaN with a low Ga composition. This study is aimed to contribute to the understanding of GaN growth on the sidewalls of c-plane trench structure SiC. The ultrathin growth technique is also hoped to be applied to the fabrication of GaN-based vertical structure nonpolar optical or electrical devices.

DOI： 10.1016/j.jcrysgro.2017.01.031

Orientation-controlled epitaxial lateral overgrowth of semipolar GaN on Si(001) with a directionally sputtered AlN buffer layer International journal

Ho-Jun Lee, Si-Young Bae, Kaddour Lekhal, Akira Tamura, Takafumi Suzuki, Maki Kushimoto, Yoshio Honda, Hiroshi Amano

JOURNAL OF CRYSTAL GROWTH Vol. 468 page： 547 - 551 2017.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We successfully grew semipolar (10 (1) over bar3) and (10 (1) over bar5) GaN films on Si(001) substrates employing metal-organic chemical vapor deposition (MOCVD) by inserting a directionally sputtered AlN (DS-AlN) buffer layer. To improve the crystal quality of the orientation-controlled semipolar (10 (1) over bar3) and (10 (1) over bar5) GaN films, a two-step epitaxial lateral overgrowth (ELO) process was performed with a striped mask. According to low-temperature cathodoluminescence (LT-CL) characterization, the ELO results in a coalesced morphology and a low defect density of < 2.72x10(8) cm(-2) for both semipolar (10<(1)over bar>3) and (10 (1) over bar5) GaN films. For comparing the properties of planar and ELO semipolar GaN, a rocking curve of x-ray diffraction (XRD) and low-temperature photoluminescence (LT-PL) spectra was measured. The crystal orientation of semipolar GaN films was confirmed using electron backscatter diffraction (EBSD).

DOI： 10.1016/j.jcrysgro.2016.11.116

Effect of V/III ratio on the surface morphology and electrical properties of m-plane (10(1)over-bar0) GaN homoepitaxial layers International journal

Ousmane I. Barry, Atsushi Tanaka, Kentaro Nagamatsu, Si-Young Bae, Kaddour Lekhal, Junya Matsushita, Manato Deki, Shugo Nitta, Yoshio Honda, Hiroshi Amano

JOURNAL OF CRYSTAL GROWTH Vol. 468 page： 552 - 556 2017.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We have investigated the effect of V/III ratio on the surface morphology, impurity concentration and electrical properties of m-plane (10 (1) over bar0) Gallium Nitride (GaN) homoepitaxial layers. Four-sided pyramidal hillocks are observed on the nominally on-axis m-plane GaN films. Hillocks sizes relatively increase by increasing the V/III ratio. All facets of pyramidal hillocks exhibit well-defined step-terrace features. Secondary ion mass spectrometry depth profiles reveal that carbon impurities decrease by increasing the V/III ratio while the lowest oxygen content is found at an optimized V/III ratio of 900. Vertical Schottky barrier diodes fabricated on the m-GaN samples were characterized. Low leakage current densities of the order of 10(-10) A/cm(2) at -5 V are obtained at the optimum V/III ratio. Oxygen impurities and screw-component dislocations around hillocks are found to have more detrimental impact on the leakage current mechanism.

DOI： 10.1016/j.jcrysgro.2016.12.012

Uneven AlGaN multiple quantum well for deep-ultraviolet LEDs grown on macrosteps and impact on electroluminescence spectral output Reviewed

Vol. 56 ( 6 ) 2017.6

Selective-area growth of vertically oriented GaN nanostructures with a hafnium pre-orienting layer International journal

S. -Y. Bae, K. Lekhal, H. -J. Lee, T. Mitsunari, J. -W. Min, D. -S. Lee, M. Kushimoto, Y. Honda, H. Amano

JOURNAL OF CRYSTAL GROWTH Vol. 468 page： 110 - 113 2017.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Severe melt-back etching has forced the epitaxy of GaN on Si to use an AlN buffer layer for growing high-quality two-dimensional layers, despite its high resistivity. Herein, we report a metal-based pre-orienting layer (POL) for growing GaN nanostructures (NSs) to replace the traditional AlN buffer layer. Two metals, titanium (Ti) and hafnium (Hf), were evaluated as POLs. We succeeded in fabricating arrays of GaN NSs with highly preferred orientation using selective-area growth. The crystallographic phase of the POLs critically affected the evolved orientation of the crystals. Photoluminescence measurements revealed that GaN NSs with Hf-based POLs were of reasonably high quality. We believe that this result will facilitate broader III-V semiconductor applications using alternative substrates moving beyond conventional Si-based optoelectronics.

DOI： 10.1016/j.jcrysgro.2016.10.032

Annealing effect on threading dislocations in a GaN grown on Si substrate International journal

H. Iwata, H. Kobayashi, T. Kamiya, R. Kamei, H. Saka, N. Sawaki, M. Irie, Y. Honda, H. Amano

JOURNAL OF CRYSTAL GROWTH Vol. 468 page： 835 - 838 2017.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Effect of rapid thermal annealing (RTA) on crystal defects in a GaN layer grown on a (111) Si substrate was investigated by photoluminescence (PL) and transmission electron microscopy (TEM) analyses. The PL spectra suggested that the density of gallium vacancy is not changed by the heat treatment up to 700 degrees C. In the TEM specimen, we had dislocation half loops generated by off-axis propagation of the threading dislocation. We found that the half-loop of c-type dislocation shrinks/moves by a repetitive RTA at 600-700 degrees C. In contrast, we could find no remarkable changes in the a-type or a+c-type dislocations.

DOI： 10.1016/j.jcrysgro.2017.01.001

III-nitride core-shell nanorod array on quartz substrates Reviewed Open Access

Vol. 7 2017.3

AlN and AlGaN layers grown on Si(111) substrate by mixed-source hydride vapor phase epitaxy method International journal

Hunsoo Jeon, Injun Jeon, Gang Seok Lee, Sung Geun Bae, Hyung Soo Ahn, Min Yang, Sam Nyung Yi, Young Moon Yu, Yoshio Honda, Nobuhiko Sawaki, Suck-Whan Kim

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 56 ( 1 ) 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

High Al-composition AlGaN and AlN epilayers were grown directly on Si(111) substrate by a hydride vapor phase epitaxy (HVPE) method with a melted mixed source in a graphite boat set in a source zone with high temperatures of T = 700 and 800 degrees C, respectively. The presence of the Ga material in the mixed source of Ga and Al promoted the growth of AlN and AlGaN epilayers in the growth zone. When the temperature in the source zone was 800 degrees C, the crystalline quality of the AlN and AlGaN epilayers increased as the ratio of Ga to Al increased, and the optimum mix ratio of Ga to Al for the growth of AlN epilayers was approximately 0.35-0.42, obtained from a numerical fitting analysis of the X-ray diffraction (XRD) data for these epilayers. It appears that they can be grown directly by our melted-mixed-source HVPE method in a high-temperature source zone. (C) 2017 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.56.01AD07

Mechanism of light emission and manufacturing process of vertical-type light-emitting diode grown by hydride vapor phase epitaxy International journal

Gang Seok Lee, Hunsoo Jeon, Hyung Soo Ahn, Min Yang, Sam Nyung Yi, Young Moon Yu, Sang Chil Lee, Yoshio Honda, Nobuhiko Sawaki, Suck-Whan Kim

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 56 ( 1 ) 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

We developed a vertical-type light-emitting diode (LED) in which the substrate is removed using a hydride vapor phase epitaxy (HVPE) apparatus consisting of a multi-graphite boat filled with a mixed source and a high-temperature (T approximate to 900 degrees C) RF heating coil outside the source zone. The new chip-growth process with a significant reduction in the number of production steps is completed in only four steps, namely, photolithography, epitaxial layer growth, sorting, and metallization. We analyze the emission mechanism of these lights from measurement results to validate the characteristics of the light emitted from these vertical-type blue LEDs and white LEDs (WLEDs) without substrates, and propose that this mixed-source HVPE method may be a promising production technique for LEDs. (C) 2017 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.56.01AD03

Development of Sustainable Smart Society based on Transformative Electronics

Development of Sustainable Smart Society based on Transformative Electronics Reviewed

page： . 2017

Ogura M, Ando Y, Usami S, Nagamatsu K, Kushimoto M, Deki M, Tanaka A, Nitta S, Honda Y, Pristovsek M, Kawai H, Yagi S, Amano H

2017 IEEE INTERNATIONAL ELECTRON DEVICES MEETING (IEDM) page： . 2017

Improved crystal quality of semipolar (10(1)over-bar3) GaN on Si(001) substrates using AlN/GaN superlattice interlayer International journal

Ho-Jun Lee, Si-Young Bae, Kaddour Lekhal, Tadashi Mitsunari, Akira Tamura, Yoshio Honda, Hiroshi Amano

JOURNAL OF CRYSTAL GROWTH Vol. 454 page： 114 - 120 2016.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The planar epitaxial growth of semipolar (10 (1) over bar3) GaN on a Si(001) substrate was performed on a directionally sputtered AlN buffer layer. Three types of interlayers, i.e., single AlN, double AlN, and a stack of AlN/GaN layers were grown by metalorganic chemical vapor deposition (MOCVD) to achieve high quality GaN films. The results for the stack of AlN/GaN layers provide highest crystal quality and optical properties for GaN. Comparing the top (Ga face) and bottom (N face) surfaces of grown semipolar (10 (1) over bar3) GaN confirms the defect density reduction that is due to the application of interlayers. Moreover, reduced inversion domain density on the bottom surface is attributed with the insertion of interlayers. Improving the quality of semipolar GaN on Si(001) substrates is expected to be useful for GaN/Si(001) integrated optoelectronics. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jcrysgro.2016.09.004

Controlled morphology of regular GaN microrod arrays by a selective area growth with HVPE International journal

Kaddour Lekhal, Si-Young Bae, Ho-Jun Lee, Tadashi Mitsunari, Akira Tamura, Manato Deki, Yoshio Honda, Hiroshi Amano

JOURNAL OF CRYSTAL GROWTH Vol. 447 page： 55 - 61 2016.8

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The selective area growth (SAG) of GaN was implemented on patterned GaN/sapphire templates by hydride vapor phase epitaxy (HVPE) to fabricate regular arrays of Ga-polar GaN microrods. The control of growth parameters such as H-2/N-2 carrier gas ratio, growth temperature, and absolute NH3/HCl gas flow resulted in changes in the growth morphology. In particular, for an optimized mixed-carrier gas ratio of H-2 to N-2, we achieved vertically well-aligned microrods. The topmost regions of the GaN microrods were terminated with pyramidal facets, indicating typical Ga polarity. The optical properties of the grown microrods were characterized by cathodoluminescence (CL) at a low temperature. This revealed that the GaN microrods had high crystal quality since they exhibited suppressed yellow luminescence as well as strong band edge emission. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jcrysgro.2016.05.008

Development of highly durable deep-ultraviolet AlGaN-based LED multichip array with hemispherical encapsulated structures using a selected resin through a detailed feasibility study International journal

Shoko Nagai, Kiho Yamada, Akira Hirano, Masamichi Ippommatsu, Masahiro Ito, Naoki Morishima, Ko Aosaki, Yoshio Honda, Hiroshi Amano, Isamu Akasaki

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 8 ) 2016.8

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

To replace mercury lamps with AlGaN-based deep-ultraviolet (DUV) LEDs, a simple and low-cost package with increased light extraction efficiency (LEE) is indispensable. Therefore, resin encapsulation is considered to be a key technology. However, the photochemical reactions induced by DUV light cause serious problems, and conventional resins cannot be used. In the former part of this study, a comparison of a silicone resin and fluorine polymers was carried out in terms of their suitability for encapsulation, and we concluded that only one of the fluorine polymers can be used for encapsulation. In the latter part, the endurance of encapsulation using the selected fluorine polymer was investigated, and we confirmed that the selected fluorine polymer can guarantee a lifetime of over 6,000 h at a wavelength of 265nm. Furthermore, a 3 x 4 array module of encapsulated dies on a simple AlN submount was fabricated, demonstrating the possibility of W/cm(2)-class lighting. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.082101

Evaluation of excess In during metal organic vapor-phase epitaxy growth of InGaN by monitoring via in situ laser scattering International journal

Tetsuya Yamamoto, Akira Tamura, Shigeyoshi Usami, Tadashi Mitsunari, Kentaro Nagamatsu, Shugo Nitta, Yoshio Honda, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 5 ) 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Using an in situ laser absorption and scattering method, the surface roughness and incorporation of In in InGaN layers grown by metal organic vapor-phase epitaxy (MOVPE) were monitored. We observed that the laser light with energy higher than the GaN bandgap was fully absorbed in a GaN layer with a smooth film surface. On the other hand, we observed that the scattering laser light from the surface when the roughness of the InGaN surface increased owing to the formation of In droplets. Laser light with energy lower than the GaN bandgap was weakly absorbed by the GaN layer and was scattered at the back surface of the wafer. Furthermore, laser light intensity decreased during InGaN growth because of In incorporation. The threshold of trimethyl-In (TMIn) for the formation of In droplets as a function of growth temperature was determined using our in situ system. Moreover, we observed that the In droplets were removed by thermal or H-2 treatment. The results indicate that multiwavelength laser absorption and scattering enable the optimization of the growth conditions for In-rich InGaN. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.05FD03

Study of radiation detection properties of GaN pn diode

Mutsuhito Sugiura, Maki Kushimoto, Tadashi Mitsunari, Kohei Yamashita, Yoshio Honda, Hiroshi Amano, Yoku Inoue, Hidenori Mimura, Toru Aoki, Takayuki Nakano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 5 ) 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Recently, GaN, which has remarkable properties as a material for optical devices and high-power electron devices, has also attracted attention as a material for radiation detectors. We previously suggested the use of BGaN as a neutron detector material. However, the radiation detection characteristics of GaN itself are not yet adequately understood. For realizing a BGaN neutron detector, the understanding of the radiation detection characteristics of GaN, which is a base material of the neutron detector, is important. In this study, we evaluated the radiation detection characteristics of GaN. We performed I-V and energy spectrum measurements under alpha ray, gamma ray, and thermal neutron irradiations to characterize the radiation detection characteristics of a GaN diode. The obtained results indicate that GaN is an effective material for our proposed new BGaN-based neutron detector. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.05FJ02

Structural and optical study of core-shell InGaN layers of nanorod arrays with multiple stacks of InGaN/GaN superlattices for absorption of longer solar spectrum International journal

Si-Young Bae, Byung Oh Jung, Kaddour Lekhal, Dong-Seon Lee, Manato Deki, Yoshio Honda, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 5 ) 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

We report on the material and optical properties of core-shell InGaN layers grown on GaN nanorod arrays. The core-shell InGaN layers were well grown on polarization-reduced surfaces such as semipolar pyramids and nonpolar sidewalls. In addition, to compensate the biaxial strain between GaN and InGaN layers, we grew interlayers underneath a thick InGaN layer. Here, the interlayers were composed of multiple superlattice structures. We could observe that the indium composition of core-shell InGaN structures increased with the number of interlayers. This indicates that the absorption energy band of InGaN alloys can be better matched to the spectral irradiance of the solar spectrum in nature. We also implemented a simulation of Ga-polar and nonpolar InGaN-based solar cells based on the indium composition obtained from the experiments. The result showed that nonpolar InGaN solar cells had a much higher efficiency than Ga-polar InGaN solar cells with the same thickness of the absorption layer. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.05FG03

Selective-area growth of GaN microrods on strain-induced templates by hydride vapor phase epitaxy International journal

Kaddour Lekhal, Si-Young Bae, Ho-Jun Lee, Tadashi Mitsunari, Akira Tamura, Manato Deki, Yoshio Honda, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 5 ) 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

In this paper, we discuss the influence of parameters such as type of carrier gas and NH3/HCl flow ratio on the growth of vertical GaN microstructures by selective-area growth (SAG) hydride vapor phase epitaxy (HVPE). On various strain-induced templates such as GaN/sapphire, GaN/Si, and AlN/Si, regular arrays of Ga-polar GaN microrods were properly achieved by adjusting the growth parameters. The photoluminescence and micro-Raman measurements reveal not only the crystal quality of the GaN microrods but also strain distribution. These results will give insight into the control of the morphology of GaN microrods in terms of the strain induced from templates in SAG-HVPE. The precisely controlled arrays of GaN microrods can be used for next-generation light-emitting diodes (LEDs) by realizing InGaN/GaN multi-quantum wells (MQWs) with a radial structure. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.05FF03

Preflow trimethylaluminum treatment effect on GaN growth on SiC with an ultrathin interlayer International journal

Zheng Sun, Kentaro Nagamatsu, Marc Olsson, Peifeng Song, Manato Deki, Shugo Nitta, Yoshio Honda, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 5 ) 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Previously, we reported a growth method for GaN on SiC by metalorganic vapor phase epitaxy. By using a preflow trimethylaluminum treatment, the poor wetting problem of gallium on the SiC surface was alleviated, resulting in a 1.2-mu m-thick crack-free GaN grown on an on-axis 6H-SiC(0001) substrate via an ultrathin AlGaN interlayer. In this study, the impact of the preflow trimethylaluminum treatment time is investigated to understand why a crack-free epilayer was realized. To demonstrate the electrical performance of devices formed by our technique, GaN/SiC vertical Schottky barrier diodes were fabricated and compared with GaN/AlN/SiC and GaN/GaN vertical Schottky barrier diodes. Compared with diodes including a high-resistance AlN interlayer, the series resistance of GaN/SiC Schottky barrier diodes incorporating the ultrathin interlayer with 5 s of TMAl treatment showed a marked reduction from 4.0 x 10(7) to 2.0 x 10(-1) Omega.cm(2). The ultrathin interlayer growth technique is expected to be applied in future GaN/SiC hybrid high-power and high-frequency devices. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.05FB06

Observation of relaxation time of surface charge limit for InGaN photocathodes with negative electron affinity International journal

Daiki Sato, Tomohiro Nishitani, Yoshio Honda, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 5 ) 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

A thin p-type InGaN with a negative electron affinity (NEA) surface was used to measure the relaxation time of a surface charge limit (SCL) by irradiating rectangular laser beam pulses at changing time interval. The p-type InGaN film was grown by metal organic vapor phase epitaxy and the NEA activation was performed after the sample was heat cleaned. 13 nC per pulse with 10ms width was obtained from the InGaN photocathode. The current decreased exponentially from the beginning of the pulse. The initial current value after the laser irradiation decreased with the time interval. As a result, the SCL relaxation time was estimated through the InGaN photocathode measurements at 100 ms. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.05FH05

Growth of semipolar (1(1)over-bar01) high-indium-content InGaN quantum wells using InGaN tilting layer on Si(001) International journal

Maki Kushimoto, Yoshio Honda, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 5 ) 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Low-toxity high-In-content InGaN is an attractive option for short-distance communications through plastic optical fibers because its performance is only slightly affected by temperature. However, its fabrication on the c-plane is impaired by In droplets and V pits, which form at low-growth temperature. On the other hand, unlike the c-plane, (1 (1) over bar 01) InGaN relaxes with tilting. Therefore, in this study, we first grew a high-In-content InGaN single layer, and then we fabricated an InGaN tilting layer between (1 (1) over bar 01) InGaN-based multiple quantum wells (MQWs) and GaN stripes/(001) Si. The emission wavelength increased with the InGaN tilting layer's growth time because the strain was relaxed by misfit dislocations at the heterointerface. This layer also extended the emission peak of InGaN/GaN MQWs and increased the photoluminescence intensity with respect to that of a single-layered InGaN. Therefore, the InGaN tilting layer is effective for growing high-In-content (1 (1) over bar 01) InGaN MQWs. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.05FA10

Growth of AlN layer on patterned sapphire substrate by hydride vapor phase epitaxy International journal

Gang Seok Lee, Chanmi Lee, Hunsoo Jeon, Chanbin Lee, Sung Geun Bae, Hyung Soo Ahn, Min Yang, Sam Nyung Yi, Young Moon Yu, Jae Hak Lee, Yoshio Honda, Nobuhiko Sawaki, Suck-Whan Kim

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 5 ) 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Even though a patterned sapphire substrate (PSS) has been used for the growth of a high-quality epilayer because of its many advantages, it has not been successfully used to grow an AlN epilayer for ultraviolet (UV) light-emitting diodes (LEDs) on a PSS up to now. We report the growth of a high-quality AlN epilayer on a PSS, as a substrate for the manufacture of UV LEDs, by hydride vapor phase epitaxy (HVPE). The X-ray diffraction (XRD) peaks for the AlN epilayer grown on the PSS indicate that crystalline AlN with a wurtzite structure was grown successfully on the PSS. Furthermore, HVPE combining both in situ HVPE technology and liquid-phase epitaxy (LPE) using a mixed source is proposed as a novel method for the growth of a flat AlN epilayer on a PSS. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.05FC02

Theoretical approach to surface reconstruction of InN(0001) during raised-pressure metalorganic vapor-phase epitaxy

Akira Kusaba, Yoshihiro Kangawa, Yoshio Honda, Hiroshi Amano, Koichi Kakimoto

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 5 ) 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

We investigated the surface reconstruction of InN(0001) during raised-pressure metalorganic vapor-phase epitaxy using an ab initio-based approach. We observed that the reconstructed structure changes from In-rich surfaces such as In bilayer and monolayer surfaces to an ideal surface with increasing growth temperature. In addition, we investigated the effects of surface reconstruction on the growth process using a newly improved thermodynamic analysis method. Although no barrier is present in the growth reaction when the In-rich surfaces appear, the results suggest that the surface phase acts as a barrier in the growth reaction when the ideal surface appears. Furthermore, we discuss the growth conditions that enable high-temperature growth with a smooth reaction path. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.05FM01

Emission Characteristics of InGaN/GaN Core-Shell Nanorods Embedded in a 3D Light-Emitting Diode International journal Open Access

Byung Oh Jung, Si-Young Bae, Seunga Lee, Sang Yun Kim, Jeong Yong Lee, Yoshio Honda, Hiroshi Amano

NANOSCALE RESEARCH LETTERS Vol. 11 ( 1 ) page： 215 2016.4

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

We report the selective-area growth of a gallium nitride (GaN)-nanorod-based InGaN/GaN multiple-quantum-well (MQW) core-shell structure embedded in a three-dimensional (3D) light-emitting diode (LED) grown by metalorganic chemical vapor deposition (MOCVD) and its optical analysis. High-resolution transmission electron microscopy (HR-TEM) observation revealed the high quality of the GaN nanorods and the position dependence of the structural properties of the InGaN/GaN MQWs on multiple facets. The excitation and temperature dependences of photoluminescence (PL) revealed the m-plane emission behaviors of the InGaN/GaN core-shell nanorods. The electroluminescence (EL) of the InGaN/GaN core-shell-nanorod-embedded 3D LED changed color from green to blue with increasing injection current. This phenomenon was mainly due to the energy gradient and deep localization of the indium in the selectively grown InGaN/GaN core-shell MQWs on the 3D architecture.

DOI： 10.1186/s11671-016-1441-6

Study of enhanced photovoltaic behavior in InGaN-based solar cells by using SiNx insertion layer: Influence of dislocations

PubMed

Seunga Lee, Yoshio Honda, Hiroshi Amano, Jongjin Jang, Okhyun Nam

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 3 ) 2016.3

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Using a SiNx insertion layer to reduce dislocations, enhanced photovoltaic properties could be obtained in p-i-n InGaN/GaN heterojunction solar cell. To investigate the influence of the dislocations on the photovoltaic behaviors, a sample grown without SiNx insertion layer was identically prepared for comparison. From optical properties measurements, the reduction in the number of non-radiative centers and a stronger In localization effect was shown in the sample with SiNx insertion layer. However, the quantum confined stark effect was almost negligible in both the samples. Electrical properties measurement showed reduced saturation current and increased shunt resistance in the sample with SiNx insertion layer due to the reduced dislocation density. By comparing these results and using a numerical model, the influence of the dislocation density on the different photovoltaic properties such as open-circuit voltage and fill factor has been confirmed. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.030306

Effect of piezoelectric field on carrier dynamics in InGaN-based solar cells International journal

Seunga Lee, Yoshio Honda, Hiroshi Amano

JOURNAL OF PHYSICS D-APPLIED PHYSICS Vol. 49 ( 2 ) 2016.1

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

To understand the effect of piezoelectric fields on carrier dynamics, we numerically investigated a simple p-GaN/i-InxGa1-xN/n-GaN solar cell structure. A reliable simulation model was obtained by comparing the experimental and simulated results in advance. The same p-i-n InGaN structures were re-simulated with and without the piezoelectric field effect, as spontaneous polarization remained unchanged. The sample with the piezoelectric field effect showed higher short current density (J(sc)), a staircase-like feature in its I-V curve, and higher open circuit voltage (V-oc) with a lower fill factor (F.F.) and reduced conversion efficiency (C.E.) than the sample with no piezoelectric fields. In addition, with increasing In fraction (x), the V-oc value gradually increased while the J(sc) value significantly decreased, correspondingly leading to a reduction in C.E. and F.F. values of the structure with the piezoelectric field effect. To solve the current loss problem, we applied various piezoelectric field elimination techniques to the simulated structures.

DOI： 10.1088/0022-3727/49/2/025103

The interface analysis of GaN grown on 0 degrees off 6H-SiC with an ultra-thin buffer layer

Zheng Sun, Akio Ohta, Seiichi Miyazaki, Kentaro Nagamatsu, Hojun Lee, Marc Olsson, Zheng Ye, Manato Deki, Yoshio Honda, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 1 ) 2016.1

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Previously, we reported a growth method by metalorganic vapor phase epitaxy using a single two- dimensional growth step, resulting in 1.2-mu m crack-free GaN directly grown on 6H-SiC substrate. The introduction of Al-treatment prior to the standard GaN growth step resulted in improved surface wetting of gallium on the SiC substrate. Transmission electron microscope and energy dispersive spectrometer analysis of the epitaxial interface to the SiC determined that an ultra-thin AlGaN interlayer had formed measuring around 2-3 nm. We expect our growth technique can be applied to the fabrication of GaN/SiC high frequency and high power devices. (C) 2016 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.55.010303

Development of AlGaN-based deep-ultraviolet (DUV) LEDs focusing on the fluorine resin encapsulation and the prospect of the practical applications International journal

Akira Hirano, Yosuke Nagasawa, Masamichi Iypommatsu, Ko Aosaki, Yoshio Honda, Hiroshi Amano, Isamu Akasaki

UV and Higher Energy Photonics: From Materials to Applications Vol. 9926 2016

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPIE-INT SOC OPTICAL ENGINEERING

AlGaN-based LEDs are expected to be useful for sterilization, deodorization, photochemical applications such as UV curing and UV printing, medical applications such as phototherapy, and sensing. Today, it has become clear that efficient AlGaN-based LED dies are producible between 355 and 250 nm with an external quantum efficiency (EQE) of 3% on flat sapphire. These dies were realized on flat sapphire without using a special technique, i.e., reduction in threading dislocation density or light extraction enhancement techniques such as the use of a photonic crystal or a patterned sapphire substrate. Despite the limited light extraction efficiency of about 8% owing to light absorption at a thick p-GaN contact layer, high EQEs of approximately 6% has been reproducible between 300 and 280 nm without using special techniques. Moreover, an EQE of 3.9% has been shown at 271 nm, despite the smaller current injection efficiency (CIE). The high EQEs are thought to correspond to the high internal quantum efficiency (IQE), indicating a small room for improving IQE. Accordingly, resin encapsulation on a simple submount is strongly desired. Recently, we have succeeded in demonstrating fluorine resin encapsulation on a ceramic sheet (chip-on-board, COB) that is mass-producible. Furthermore, the molecular structure of a resin with a durability of more than 10,000 h is explained in this paper from the photochemical viewpoint. Thus, the key technologies of AlGaN-based DUV-LEDs having an EQE of 10% within a reasonable production cost have been established. The achieved efficiency makes AlGaN-based DUV-LEDs comparable to high-pressure mercury lamps.

DOI： 10.1117/12.2235398

Highly elongated vertical GaN nanorod arrays on Si substrates with an AlN seed layer by pulsed-mode metal-organic vapor deposition International journal

Si-Young Bae, Byung Oh Jung, Kaddour Lekhal, Sang Yun Kim, Jeong Yong Lee, Dong-Seon Lee, Manato Deki, Yoshio Honda, Hiroshi Amano

CRYSTENGCOMM Vol. 18 ( 9 ) page： 1505 - 1514 2016

Language：English Publishing type：Research paper (scientific journal) Publisher：ROYAL SOC CHEMISTRY

To extend the availability of nanostructure-based optoelectronic applications, vertically elongated nanorods with precisely controlled morphology are required. For group III nitrides, pulsed-mode growth has recently been reported as an effective method for growing nanorod arrays with geometric precision. Here, we demonstrated the growth of arrays of highly elongated nanorods on Si substrates by metal-organic chemical vapor deposition using a pulsed-mode approach. Unlike the thick and high (or middle)-quality GaN templates normally used, nanorod growth was performed on an ultrathin and low-quality AlN/Si platform. Using kinetically controlled growth conditions and a patterning process, exceptionally long GaN nanorods were achieved with high geometric precision. The grown nanorods showed considerably improved optical and structural properties while remaining in uniform arrays. This approach can be used with a variety of materials to obtain nanorods with high quality, high uniformity, and high aspect ratio, and it can also serve as an effective fabrication method for InAlGaN-alloyed core/shell nanostructures for optoelectronic nano-devices with ultrahigh efficiency.

DOI： 10.1039/c5ce02056e

Excitation density dependence of radiative and nonradiative recombination lifetimes in InGaN/GaN multiple quantum wells International journal Open Access

Hideaki Murotani, Yoichi Yamada, Yoshio Honda, Hiroshi Amano

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Vol. 252 ( 5 ) page： 940 - 945 2015.5

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

The optical properties of InGaN/GaN multiple quantum wells (MQWs) have been studied by means of photoluminescence (PL) and time-resolved photoluminescence (TRPL) spectroscopy. The radiative and nonradiative recombination lifetimes were evaluated as a function of the excitation energy density. The radiative recombination lifetime decreased and subsequently reached a nearly constant value with increasing excitation energy density, which was attributed to screening of internal electric fields by photoexcited carriers. On the other hand, the nonradiative recombination lifetime increased and subsequently decreased with increasing excitation energy density. The initial increase in the nonradiative recombination lifetime could be attributed to saturation of nonradiative recombination centers with photoexcited carriers. The nonradiative recombination lifetime was found to decrease to a considerably weaker extent than that expected for the Auger recombination process of free carriers. This indicated that the decrease in the internal quantum efficiency (IQE) at high carrier densities could not be explained only by the Auger recombination process of free carriers. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

DOI： 10.1002/pssb.201451491

Optically pumped lasing properties of (1-101) InGaN/GaN stripe multiquantum wells with ridge cavity structure on patterned (001) Si substrates Reviewed

Vol. 8 ( 2 ) page： 022702 2015.2

Optically pumped lasing properties of (1-101) InGaN/GaN stripe multiquantum wells with ridge cavity structure on patterned (001) Si substrates Reviewed

Maki Kushimoto, Tomoyuki Tanikawa, Yoshio Honda, Hiroshi Amano

Applied Physics Express Vol. 8 ( 2 ) page： 022702 2015.2

Optically pumped lasing properties of (1(1)over-bar01) InGaN/GaN stripe multiquantum wells with ridge cavity structure on patterned (001) Si substrates International journal

Maki Kushimoto, Tomoyuki Tanikawa, Yoshio Honda, Hiroshi Amano

APPLIED PHYSICS EXPRESS Vol. 8 ( 2 ) 2015.2

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

We demonstrated lasing action and investigated the optical properties of (1 (1) over bar 01) multiquantum-well (MQW) stripe crystals on patterned (001) Si substrates. Longitudinal and higher order transverse modes were observed from a ridge waveguide structure. These results strongly suggest the possibility of fabricating (1 (1) over bar 01) InGaN MQW laser diodes on (001) Si. (C) 2015 The Japan Society of Applied Physics

DOI： 10.7567/APEX.8.022702

Highly ordered catalyst-free InGaN/GaN core-shell architecture arrays with expanded active area region International journal

Byung Oh Jung, Si-Young Bae, Sang Yun Kim, Seunga Lee, Jeong Yong Lee, Dong-Seon Lee, Yoshihiro Kato, Yoshio Honda, Hiroshi Amano

NANO ENERGY Vol. 11 page： 294 - 303 2015.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Highly ordered, position-controlled gallium nitride (GaN) nanowire based multiple-quantum-wells (MQWs) core-shell architecture arrays are synthesized by metalorganic chemical vapor deposition (MOCVD). We investigate the possibility of using GaN nanowire arrays as a basal template for the growth of InxGa1-xN/GaN MQWs. The MQWs on three different crystal facets (c(-), m(-), and semipolar-plane) of GaN nanowire exhibit dissimilar structural properties. The structural characteristics of InGaN/GaN core-shell arrays are inspected by cross-sectional high-resolution transmission electron microscopy (HR-TEM). We also investigate the optical properties of MQW core-shell structure nanoarrays. The luminescent characteristics of InGaN/GaN core-shell structure arrays are determined by photoluminescence (PL) and cathodoluminescence (CL) measurements. The monochromatic CL images clearly show the light emission behavior of InGaN/GaN MQW coaxial structure. Two distinguishable light emission peaks were observed in the GaN nanowire based core-shell structure. The characteristic of light emission mainly depends on the properties of MQWs, which are generated from different crystal facets of GaN. In addition, the light emission intensity shows different behaviors depending on the area of the GaN nanowire m-plane. The results of this study suggest that GaN nanowire arrays can be used as a good alternative basal template for next-generation light-emitting diodes (LEDs). (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.nanoen.2014.11.003

GaN/SiC Epitaxial growth for high power and high switching speed device applications Reviewed

Zheng Sun, Shigeyoshi Usami, Di Lu, Takahiro Ishii, Marc Olsson, Kouhei Yamashita, Tadashi Mitsunari, Yoshio Honda, Hiroshi Amano

Materials Research Society Symposium Proceedings Vol. 1736 page： 65 - 69 2015

Language：English Publishing type：Research paper (international conference proceedings) Publisher：Materials Research Society

We developed a new GaN on SiC growth method by metalorganic vapour phase epitaxy (MOVPE) using of a single 2-dimension-growth step. Prior to epitaxy, to inhibit pre-reaction of Si-face SiC substrate with TMGa and NH&lt
inf&gt
3&lt
/inf&gt
, TMA1 was flowed without NH&lt
inf&gt
3&lt
/inf&gt
. 1.5 μm of undoped crack-firee GaN was grown on 6H-SiC (Si-face). Without buffer layer, the vertical resistance of GaN/SiC structure was found to be around 82.1Ω as determined by I-V characteristic. Further reduction in vertical resistance is expected by growth of n-GaN (1.5 μm)/SiC structure (300 μm). We also expect a SiC-based GaN heterostructure vertical FET will achieve high power and high switching speed performance.

DOI： 10.1557/opl.2015.102

Photocathode electron beam sources using GaN and InGaN with NEA Reviewed

T. Nishitani, T. Maekawa, M. Tabuchi, T. Meguro, Y. Honda, H. Amano

GALLIUM NITRIDE MATERIALS AND DEVICES X Vol. 9363 2015

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPIE-INT SOC OPTICAL ENGINEERING

A photocathode electron source using p-type GaN and p-type InGaN semiconductors with a negative electron affinity (NEA) surface has been studied for its ability to maintain an extended NEA state. The key technology of NEA photocathodes is the formation of electric dipoles by atoms on the surface, which makes it possible for photo excited electrons in the conduction band minimum to escape into the vacuum. This means that in order to keep the electron energy spread as small as possible, the excitation photon energy should be tuned to the band gap energy. However, the NEA surface is damaged by the adsorption of residual gas and the back-bombardment of ionized residual gas by photoelectrons. The p-type GaN and InGaN semiconductors were measured a lifetime of quantum yield of excitation energy corresponding to the band gap energy in comparison to the p-type GaAs as the conventional NEA photocathode. Lifetime of NEA-photocathodes using the GaN and InGaN were 21 times and 7.7 times longer respectively than that using the GaAs.

DOI： 10.1117/12.2076681

Nature of yellow luminescence band in GaN grown on Si substrate International journal

Shogo Ito, Taihei Nakagita, Nobuhiko Sawaki, Hyung Soo Ahn, Masashi Irie, Toshiki Hikosaka, Yoshio Honda, Masahito Yamaguchi, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 53 ( 11 ) 2014.11

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

High-optical-quality GaN was grown on a (111) Si substrate by metal-organic vapor phase epitaxy using an AlInN buffer layer and an indium doped AlN nucleation layer. The photoluminescence spectra at room temperature showed a strong and narrow edge-emission peak and weak defect-related emission bands. We found four spectral peaks in the green and yellow luminescence bands at G(0): 514.5 nm (2.410 eV), G(1): 546.5nm (2.269 eV), Y-1: 553.5nm (2.240 eV), and Y-0: 584.5nm (2.121 eV), independent of the growth methods/conditions. The results suggest that the emission is associated with an intrinsic defect such as a Ga vacancy. (C) 2014 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.53.11RC02

Quantum Efficiency and Life Time of GaN and InGaN with NEA-surface Reviewed International journal

Sato Daiki, Nishitani Tomohiro, Maekawa Takuya, Honda Yoshio, Amano Hiroshi

IEICE technical report. Component parts and materials Vol. 114 ( 202 ) page： 49-54 - 54 2014.9

Language：English Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

The photocathode using Negative Electron Affinity (NBA) surface on a semiconductor has been applied for science technologies such as an elemental particle experiment as an electron beam source. Yet, since NBA-surface is fragile, it is necessary to figure out how to make its life time longer in order to develop new technologies. Then, we realized that considering the band gap in semiconductor, the life time becomes longer as the negative affinity goes even smaller. Therefore, we produced the photocathodes using GaN and InGaN that have wider band gaps than that of GaAs. As a result, using GaN and InGaN, we gained 17 times and 7 times longer life time NEA-surface than that of GaAs, respectively. On the other hand, the result indicates that we can produce the NEA-surface with only cesium.

P-GaN by Mg Ion Implantation for Power Device Applications (シリコン材料・デバイス) Reviewed International journal

SUN Zheng, Olsson Marc, NAGAYAMA Tsutomu, HONDA Yoshio, AMANO Hiroshi

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 Vol. 114 ( 58 ) page： 109-112 - 112 2014.5

Language：English Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

We realized p-GaN by high temperature Mg ion implantation with pre-sputter(PS) technique. Due to the new PS technique and high temperature implantation, ion implantation damage was greatly reduced. This soft implantation made the post anneal more effectively to recover the implantation damage and activate the implanted Mg ions. We believe this p-GaN by Mg ion implantation will contribute to GaN to enter high output power device application field.

P-GaN by Mg Ion Implantation for Power Device Applications Reviewed

SUN Zheng, Olsson Marc, NAGAYAMA Tsutomu, HONDA Yoshio, AMANO Hiroshi

IEICE technical report. Component parts and materials Vol. 114 ( 57 ) page： 109-112 - 112 2014.5

Language：English Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

P-GaN by Mg Ion Implantation for Power Device Applications

SUN Zheng, Olsson Marc, NAGAYAMA Tsutomu, HONDA Yoshio, AMANO Hiroshi

IEICE technical report. Electron devices Vol. 114 ( 56 ) page： 109-112 - 112 2014.5

Language：English Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Characterization of nonpolar a-plane InGaN/GaN multiple quantum well using double nanopillar SiO2 mask Reviewed International journal

Ji-Su Son, Yoshio Honda, Masahito Yamaguchi, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 53 ( 5 ) 2014.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

The characteristics of nonpolar a-plane (11 (2) over bar0) GaN (a-GaN) grown using single and double nanopillar SiO2 masks were investigated. The two nanopillar SiO2 masks were directly fabricated on an r-plane sapphire substrate and a-GaN by the epitaxial lateral overgrowth (ELOG) technique. Through the use of the single and double nanopillar SiO2 masks, the crystalline quality and optical properties of a-GaN were markedly improved because of the nanoscale ELOG effect and a number of voids in the single and double nanopillar SiO2 mask areas in comparison with the planar sample. The submicron pit densities of the planar, single, and double nanopillar mask samples were similar to 2 x 10(9), similar to 7 x 10(8), and similar to 4 x 10(8) cm(-2), respectively. The internal quantum efficiency (IQE) values at room temperature of three-period InGaN/GaN multiple quantum wells (MQWs) grown using the planar, single, and double nanopillar masks were 45, 60, and 68% at a carrier concentration of 1.0 x 10(18) cm(-3), respectively. (C) 2014 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.53.05FL01

In situ X-ray investigation of changing barrier growth temperatures on InGaN single quantum wells in metal-organic vapor phase epitaxy Reviewed International journal

Guangxu Ju, Yoshio Honda, Masao Tabuchi, Yoshikazu Takeda, Hiroshi Amano

JOURNAL OF APPLIED PHYSICS Vol. 115 ( 9 ) 2014.3

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

The effects of GaN quantum barriers with changing growth temperatures on the interfacial characteristics of GaN/InGaN single quantum well (SQW) grown on GaN templates by metalorganic vapour phase epitaxy were in situ investigated by X-ray crystal truncation rod (CTR) scattering and X-ray reflectivity measurements at growth temperature using a laboratory level X-ray diffractometer. Comparing the curve-fitting results of X-ray CTR scattering spectra obtained at growth temperature with that at room temperature, the InxGa1-xN with indium composition less than 0.11 was stabile of the indium distribution at the interface during the whole growth processes. By using several monolayers thickness GaN capping layer to protect the InGaN well layer within temperature-ramping process, the interfacial structure of the GaN/InGaN SQW was drastically improved on the basis of the curve-fitting results of X-ray CTR scattering spectra, and the narrow full width at half-maximum and strong luminous intensity were observed in room temperature photoluminescence spectra. (C) 2014 AIP Publishing LLC.

DOI： 10.1063/1.4867640

Growth of InGaN/GaN multiple quantum wells on size-controllable nanopyramid arrays Reviewed International journal

Cao Miao, Yoshio Honda, Masahito Yamaguchi, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 53 ( 3 ) 2014.3

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Regularly distributed nanopyramid arrays with a highly uniform size were grown by selective-area growth. The nanopyramid size could be tuned by varying the growth time. Two emission peaks were observed from multiple quantum wells grown on the nanopyramids. The longer-wavelength peak originated from the apexes of pyramids with threefold symmetry. High-density stacking faults observed at these triangular apexes might be responsible for the higher indium incorporation. The formation of embedded voids inside the pyramids was explained by the different growth rates at the edge and center of the mask window caused by the low diffusion length. (C) 2014 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.53.030306

Novel activation process for Mg-implanted GaN International journal

Shin Hashimoto, Takao Nakamura, Yoshio Honda, Hiroshi Amano

JOURNAL OF CRYSTAL GROWTH Vol. 388 page： 112 - 115 2014.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

A novel activation process for Mg-implanted GaN was demonstrated. As opposed to the conventional thermal annealing process, an H-2/NH3 alternating supply annealing process achieved better optical activation, stronger near-ullraviolel luminescence and weaker yellow luminescence in the phololuminescence spectroscopy. After this process, small hexagonal hillocks were observed on the surface, which indicated that crystal regrowth was induced by this process, consisting of decomposition of GaN by H-2 supplies and re-crystallization by NH3 supplies. It was revealed that the implanted Mg could easily be located at the activation site by means of crystal regrowth by this process. (C) 2013 Elsevier B.V. All rights reserved

DOI： 10.1016/j.jcrysgro.2013.07.011

Growth of low-defect-density nonpolar a-plane GaN on r-plane sapphire using pulse NH3 interrupted etching Reviewed International journal Open Access

Ji-Su Son, Yoshio Honda, Hiroshi Amano

OPTICS EXPRESS Vol. 22 ( 3 ) page： 3585 - 3592 2014.2

Language：English Publishing type：Research paper (scientific journal) Publisher：OPTICAL SOC AMER

Nonpolar a-plane (11-20) GaN (a-GaN) layers with low overall defect density and high crystalline quality were grown on r-plane sapphire substrates using etched a-GaN. The a-GaN layer was etched by pulse NH3 interrupted etching. Subsequently, a 2-mu m-thick Si-doped a-GaN layer was regrown on the etched a-GaN layer. A fully coalescent n-type a-GaN layer with a low threading dislocation density (similar to 7.5 x 10(8) cm(-2)) and a low basal stacking fault density (similar to 1.8 x 10(5) cm(-1)) was obtained. Compared with a planar sample, the full width at half maximum of the (11-20) X-ray rocking curve was significantly decreased to 518 arcsec along the c-axis direction and 562 arcsec along the m-axis direction. (C) 2014 Optical Society of America

DOI： 10.1364/OE.22.003585

PubMed

Reduction of efficiency droop in InGaN light-emitting diodes on low dislocation density GaN substrate Reviewed

page： 90030E-90030E-6 2014

Characterization of nonpolar a-plane InGaN/GaN multiple quantum well using double nanopillar SiO2 mask Reviewed

Vol. 53 ( 5S1 ) page： 05FL01 2014

Growth of low-defect-density nonpolar a-plane GaN on r-plane sapphire using pulse NH 3 interrupted etching Reviewed

Vol. 22 ( 3 ) page： 3585-3592 2014

Enhancement of light output power on GaN-based light-emitting diodes using two-direction stripe-patterned sapphire substrate Reviewed

Vol. 11 ( 3‐4 ) page： 722-725 2014

Growth of InGaN/GaN multiple quantum wells on size-controllable nanopyramid arrays Reviewed

Vol. 53 ( 3 ) page： 30306 2014

Morphology development of GaN nanowires using a pulsed-mode MOCVD growth technique Reviewed

Vol. 16 ( 11 ) page： 2273-2282 2014

X-ray investigations of GaInN single quantum wells grown by atomic layer epitaxy and metalorganic vapor phase epitaxy Reviewed

Vol. 11 ( 3‐4 ) page： 393-396 2014

In situ X-ray investigation of changing barrier growth temperatures on InGaN single quantum wells in metal-organic vapor phase epitaxy Reviewed

Vol. 115 ( 9 ) page： 94906 2014

Novel activation process for Mg-implanted GaN Reviewed

Vol. 388 page： 112-115 2014

Recombination dynamics and internal quantum efficiency in InGaN nanowires Reviewed Open Access

Vol. 11 ( 3-4 ) page： 652 - 655 2014

X-ray investigations of GaInN single quantum wells grown by atomic layer epitaxy and metalorganic vapor phase epitaxy Reviewed

Vol. 11 ( 3-4 ) page： 393 - 396 2014

Reduction of efficiency droop in InGaN light-emitting diodes on low dislocation density GaN substrate International journal

Kouhei Yamashita, Tomohiko Sugiyama, Makoto Iwai, Yoshio Honda, Takashi Yoshino, Hiroshi Amano

LIGHT-EMITTING DIODES: MATERIALS, DEVICES, AND APPLICATIONS FOR SOLID STATE LIGHTING XVIII Vol. 9003 2014

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPIE-INT SOC OPTICAL ENGINEERING

A GaN layer of 20 mu m thickness grown by the liquid-phase epitaxy on c-plane sapphire was used as a template for the growth of blue light-emitting diodes (LEDs) with emission peak wavelengths of about 450 nm. As the underlying layer of the active region, an InGaN/GaN superlattice or two pairs of 100 nm undoped GaN and 20 nm GaN: Si layers on an n-type GaN: Si layer was found to be effective for reducing the forward voltage. By optimizing the multiple-quantumwell structure, LEDs having a 2.5-nm-thick InGaN well and 5-nm-thick GaN barrier exhibited the highest internal quantum efficiency (IQE) at both low and high currents. This IQE was much higher than that of LEDs on a sapphire substrate. The IQE of LEDs using the liquid-phase GaN grown on sapphire substrate exceeded more than 75% at a forward current density of over 200 A/cm(2).

DOI： 10.1117/12.2038764

Morphology development of GaN nanowires using a pulsed-mode MOCVD growth technique Reviewed International journal

Byung Oh Jung, Si-Young Bae, Yoshihiro Kato, Masataka Imura, Dong-Seon Lee, Yoshio Honda, Hiroshi Amano

CRYSTENGCOMM Vol. 16 ( 11 ) page： 2273 - 2282 2014

Language：English Publishing type：Research paper (scientific journal) Publisher：ROYAL SOC CHEMISTRY

In this paper, we demonstrate a scalable process for the precise position-controlled selective growth of GaN nanowire arrays by metalorganic chemical vapor deposition (MOCVD) using a pulsed-mode growth technique. The location, orientation, length, and diameter of each GaN nanowire are controlled via pulsed-mode growth parameters such as growth temperature and precursor injection and interruption durations. The diameter and length of each GaN nanowire are in the ranges of more than 240 nm and 250-1250 nm, respectively, with different vertical-to-lateral aspect ratios that depend on the growth temperature. Also, it is found that a higher growth temperature helps increase the vertical growth rate and reduces the lateral growth rate of GaN nanowire arrays. Furthermore, in the case of longer TMGa injection duration, the Ga-rich region allows the higher lateral growth rate of GaN nanostructures, which leads to a transition in the morphology from nanowires to a thin film, while in the case of longer NH3 injection duration, the surface morphology changes from nanowires to pyramidal structures. In addition, the surface structure can also be controlled by varying the precursor interruption duration. Finally, we report and discuss a growth model for GaN nanowire arrays under pulsed-mode MOCVD growth.

DOI： 10.1039/c3ce42266f

MOVPE法によるGaN及びAlGaNへのCドーピングに関する研究 (レーザ・量子エレクトロニクス)

Enhancement of light output power on GaN-based light-emitting diodes using two-direction stripe-patterned sapphire substrate Reviewed International journal

Vol. 11 ( 3-4 ) page： 722 - 725 2014

X-ray investigations of GaInN single quantum wells grown by atomic layer epitaxy and metalorganic vapor phase epitaxy Reviewed

Ju, Guangxu, Kato, Yoshihiro, Honda, Yoshio, Tabuchi, Masao, Takeda, Yoshikazu, Amano, Hiroshi

physica status solidi (c) Vol. 11 ( 3‐4 ) page： 393-396 2014

Reduction of efficiency droop in InGaN light-emitting diodes on low dislocation density GaN substrate Reviewed

Yamashita, Kouhei, Sugiyama, Tomohiko, Iwai, Makoto, Honda, Yoshio, Yoshino, Takashi, Amano, Hiroshi

SPIE OPTO page： 90030E-90030E-6 2014

Characterization of nonpolar a-plane InGaN/GaN multiple quantum well using double nanopillar SiO2 mask Reviewed

Son, Ji-Su, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

Japanese Journal of Applied Physics Vol. 53 ( 5S1 ) page： 05FL01 2014

Growth of low-defect-density nonpolar a-plane GaN on r-plane sapphire using pulse NH 3 interrupted etching Reviewed

Son, Ji-Su, Honda, Yoshio, Amano, Hiroshi

Optics express Vol. 22 ( 3 ) page： 3585-3592 2014

Growth of InGaN/GaN multiple quantum wells on size-controllable nanopyramid arrays Reviewed

Miao, Cao, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

Japanese Journal of Applied Physics Vol. 53 ( 3 ) page： 30306 2014

Enhancement of light output power on GaN-based light-emitting diodes using two-direction stripe-patterned sapphire substrate Reviewed

Okuno, Koji, Oshio, Takahide, Shibata, Naoki, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

physica status solidi (c) Vol. 11 ( 3‐4 ) page： 722-725 2014

In situ X-ray investigation of changing barrier growth temperatures on InGaN single quantum wells in metal-organic vapor phase epitaxy Reviewed

Ju, Guangxu, Honda, Yoshio, Tabuchi, Masao, Takeda, Yoshikazu, Amano, Hiroshi

Journal of Applied Physics Vol. 115 ( 9 ) page： 94906 2014

Novel activation process for Mg-implanted GaN Reviewed

Hashimoto, Shin, Nakamura, Takao, Honda, Yoshio, Amano, Hiroshi

Journal of Crystal Growth Vol. 388 page： 112-115 2014

Morphology development of GaN nanowires using a pulsed-mode MOCVD growth technique Reviewed

Jung, Byung Oh, Bae, Si-Young, Kato, Yoshihiro, Imura, Masataka, Lee, Dong-Seon, Honda, Yoshio, Amano, Hiroshi

CrystEngComm Vol. 16 ( 11 ) page： 2273-2282 2014

若杉侑矢, 本田善央, 天野浩

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 Vol. 113 ( 331 ) page： 47 - 50 2013.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

MOVPE法を用いてGaN及びAlGaNへのMgとCの同時ドーピングを行い、電気的、光学的特性を評価した。GaNへの同時ドーピングでは比較的低濃度のCドーピングにより正孔密度の増加が確認できたが、AlGaNにおいてはC_2H_2流量増加に伴い正孔密度は減少した。cathodeluminescence(CL)測定により、全ての試料で440nm付近の発光を確認した。GaNへのMgとCのδドーピングを行った試料に対して同様の測定を行った。MgとCの同時δドーピングは通常のMgドーピングよりも高い正孔密度を示した。

高輝度電子ビーム源を目指したNEA表面p-GaNの量子効率 (電子部品・材料)

前川拓也, 本田善央, 天野浩, 西谷智博

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 Vol. 113 ( 330 ) page： 43 - 46 2013.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

我々は、負の電子親和力を持つ半導体表面を用いた電子源(NEA半導体フォトカソード電子源)の高輝度、高耐久化を目指して、p-GaN半導体を用いた機能性表面の寿命に対する電子源の高輝度条件を検討した。超高真空中でp-GaN基板に対してNEA表面活性化を行った後、その量子効率の波長依存性及びその寿命の測定実験を行った。その結果から、p-GaN基板は、従来技術のp-GaAs基板に比べて20倍以上寿命が長く、より高耐久性能を持つことが分かった。また、表面機能が低下するに連れて、バンドギャップエネルギー以下の励起エネルギーでの量子効率が優先的に減少することが分かった。これらの結果より、p-GaN基板を用いたNEA半導体フォトカソード電子源は、高耐久である一方で、表面機能が劣化した状態がより電子ビーム源として単色化に適していることを明らかにした。

高輝度電子ビーム源を目指したNEA表面p-GaNの量子効率 (電子デバイス)

前川拓也, 本田善央, 天野浩, 西谷智博

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 Vol. 113 ( 329 ) page： 43 - 46 2013.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

高輝度電子ビーム源を目指したNEA表面p-GaNの量子効率 (レーザ・量子エレクトロニクス)

前川拓也, 本田善央, 天野浩, 西谷智博

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 Vol. 113 ( 331 ) page： 43 - 46 2013.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

MOVPE法によるGaN及びAlGaNへのCドーピングに関する研究 (電子部品・材料)

若杉侑矢, 本田善央, 天野浩

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 Vol. 113 ( 330 ) page： 47 - 50 2013.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

MOVPE法によるGaN及びAlGaNへのCドーピングに関する研究 (電子デバイス)

若杉侑矢, 本田善央, 天野浩

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 Vol. 113 ( 329 ) page： 47 - 50 2013.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

Effects of Nano- and Microscale SiO

Son Ji-Su, Miao Cao, Honda Yoshio, Yamaguchi Masahito, Amano Hiroshi, Seo Yong Gon, Hwang Sung-Min, Baik Kwang Hyeon

Jpn J Appl Phys Vol. 52 ( 8 ) page： 08JC04 - 08JC04-4 2013.8

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Applied Physics

We report on the combined effects of a-plane GaN layers on a nanoscale patterned insulator on an r-plane sapphire substrate and epitaxial lateral overgrowth (ELOG) techniques. The fully coalescent a-plane GaN layer using nano- and microscale SiO<inf>2</inf>masks showed the formation of nano- and microscale voids on the masks, respectively. Atomic force microscopy (AFM) measurements revealed a surface roughness of 0.63 nm and a submicron pit density of {\sim}7.8 \times 10^{7} cm-2. Photoluminescence (PL) intensity was enhanced by a factor of 9.0 in comparison with that of a planar sample. Omega full-width at half-maximum (FWHM) values of the (11\bar{2}0) X-ray rocking curve along the c- and m-axes were 553 and 788 arcsec, respectively. A plan-view cathodoluminescence (CL) mapping image showed high luminescence intensity on the SiO<inf>2</inf>masks.

DOI： 10.7567/JJAP.52.08JC04

GaN Overgrowth on Thermally Etched Nanoporous GaN Template

Cao Miao, Yoshio Honda, Masahito Yamaguchi, Hiroshi Amano

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 52 ( 8 ) page： 08JB03 2013.8

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

A thermal-etching process for fabricating nanoporous GaN templates in a metalorganic vapor phase epitaxy (MOVPE) reactor was proposed. Such nanoporous templates exhibited nearly complete strain relaxation and considerably increased photoluminescence (PL) intensity. The threading dislocation density (TDD) after overgrowth was reduced from 3 x 10(9) to 4 x 10(8) cm(-2) for the template with poor quality, whereas little improvement was observed for the high-quality template (TDD, 4 x 10(8) cm(-2)). Multiple quantum wells (MQWs) grown on a nanoporous template fabricated from the high-quality GaN template were used to assess the effect on LED performance. The PL intensity of the sample with a nanoporous structure showed a twofold increase in PL intensity compared with the control sample. (C) 2013 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.52.08JB03

Progress and Prospect of the Growth of Wide-Band-Gap Group III Nitrides: Development of the Growth Method for Single-Crystal Bulk GaN Reviewed

Emission Wavelength Dependence of Internal Quantum Efficiency in InGaN Nanowires Reviewed

H. Murotani, H. Andoh, T. Tsukamoto, T. Sugiura, Y. Yamada, T. Tabata, Y. Honda, M. Yamaguchi, H. Amano

Jpn. J. Appl. Phys. Vol. 52 ( 8 ) page： 08JE10 2013.8

Correlation between internal quantum efficiency and degree of localization in InGaN nanowires Reviewed

H. Murotani, H. Andoh, T. Tsukamoto, T. Sugiura, Y. Yamada, T. Tabata, Y. Honda, M. Yamaguchi, H. Amano

10th Inter. Conf. Nitride Semiconductors 2013.8

Recombination dynamics of localized excitons in InGaN nanowires Reviewed

H. Murotani, H. Andoh, T. Tsukamoto, T. Sugiura, Y. Yamada, T. Tabata, Y. Honda, M. Yamaguchi, H. Amano

18th Inter. Conf. Electron dynamics in Semiconductors, Optoelectronics, and Nanostructures, TuP-6 2013.7

Structural evolution of AlN buffer and crystal quality of GaN films on a- and c-sapphire grown by metalorganic vapor phase epitaxy Reviewed

K. Okuno, T. Oshio, N. Shibata, Y. Honda, M. Yamaguchi, S. Tanaka, and H. Amano

phys. stat. sol. (c) Vol. 10 ( 3 ) page： 369-372 2013.3

Structural evolution of AlN buffer and crystal quality of GaN films on a- and c-sapphire grown by metalorganic vapor phase epitaxy Reviewed

K. Okuno, T. Oshio, N. Shibata, Y. Honda, M. Yamaguchi, S. Tanaka, and H. Amano

phys. stat. sol. (c) Vol. 10 ( 3 ) page： 369-372 2013.3

Structural evolution of AlN buffer and crystal quality of GaN films on a- and c-sapphire grown by metalorganic vapor phase epitaxy Reviewed

K. Okuno, T. Oshio, N. Shibata, Y. Honda, M. Yamaguchi, S. Tanaka, H. Amano

phys. stat. sol. (c) Vol. 10 ( 3 ) page： 369-372 2013.3

Structural evolution of AlN buffer and crystal quality of GaN films on a- and c-sapphire grown by metalorganic vapor phase epitaxy Reviewed

K. Okuno, T. Oshio, N. Shibata, Y. Honda, M. Yamaguchi, S. Tanaka, H. Amano

phys. stat. sol. (c) Vol. 10 ( 3 ) page： 369-372 2013.3

Growth of GaN on Si (111) Substrates via a Reactive-Sputter-Deposited AlN Intermediate Layer Reviewed

Yamada, Takaya; Tanikawa, Tomoyuki; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi;

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JB16 2013

Fabrication of InGaN/GaN Multiple Quantum Wells on (1bar 101) GaN Reviewed

Tanikawa, Tomoyuki; Sano, Tomotaka; Kushimoto, Maki; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi;

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JC05 2013

Stacking Faults and Luminescence Property of InGaN Nanowires Reviewed

Tabata, Takuya; Paek, Jihyun; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi;

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JE06 2013

Effects of nano-and microscale SiO2 masks on the growth of a-plane GaN layers on r-plane sapphire Reviewed

Son, Ji-Su; Miao, Cao; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi; Seo, Yong Gon; Hwang, Sung-Min; Baik, Kwang Hyeon;

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JC04 2013

Characteristics of a-plane GaN films grown on optimized silicon-dioxide-patterned r-plane sapphire substrates Reviewed

Son, Ji-Su; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi; Baik, Kwang Hyeon; Seo, Yong Gon; Hwang, Sung-Min;

Thin Solid Films Vol. 546 page： 108-113 2013

Defects generation and annihilation in GaN grown on patterned silicon substrate Reviewed

Sawaki, N; Ito, S; Nakagita, T; Iwata, H; Tanikawa, T; Irie, M; Honda, Y; Yamaguchi, M; Amano, H;

SPIE OPTO page： 86250K-86250K-6 2013

High internal quantum efficiency blue-green light-emitting diode with small efficiency droop fabricated on low dislocation density GaN substrate Reviewed

Sano, Tomotaka; Doi, Tomohiro; Inada, Shunko Albano; Sugiyama, Tomohiko; Honda, Yoshio; Amano, Hiroshi; Yoshino, Takashi;

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JK09 2013

Growth mode and threading dislocation behavior of GaN films grown on patterned sapphire substrate with radial stripe pattern Reviewed

Okuno, Koji; Oshio, Takahide; Shibata, Naoki; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi;

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JB09 2013

Thick InGaN Growth by Metal Organic Vapor Phase Epitaxy with Sputtered InGaN Buffer Layer Reviewed

Ohata, Toshiya; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi;

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JB11 2013

GaN Nanowires Grown on a Graphite Substrate by Radio Frequency Molecular Beam Epitaxy Reviewed

Nakagawa, Shinta; Tabata, Takuya; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi;

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JE07 2013

Effects of exciton localization on internal quantum efficiency of InGaN nanowires Reviewed

Murotani, Hideaki; Yamada, Yoichi; Tabata, Takuya; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi;

Journal of Applied Physics Vol. 114 ( 15 ) page： 153506 2013

GaN Overgrowth on Thermally Etched Nanoporous GaN Template Reviewed

Miao, Cao; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi;

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JB03 2013

Strain-Compensated Effect on the Growth of InGaN/AlGaN Multi-Quantum Well by Metalorganic Vapor Phase Epitaxy Reviewed

Doi, Tomohiro; Honda, Yoshio; Yamaguchi, Masahito; Amano, Hiroshi;

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JB14 2013

Progress and Prospect of the Growth of Wide-Band-Gap Group III Nitrides: Development of the Growth Method for Single-Crystal Bulk GaN Reviewed

Amano, Hiroshi;

Japanese Journal of Applied Physics Vol. 52 ( 5R ) page： 50001 2013

Structural evolution of AlN buffer and crystal quality of GaN films on a- and c-sapphire grown by metalorganic vapor phase epitaxy Reviewed

Okuno Koji, Oshio Takahide, Shibata Naoki, Honda Yoshio, Yamaguchi Masahito, Tanaka Shigeyasu, Amano Hiroshi

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 10, NO 3 Vol. 10 ( 3 ) page： 369 - 372 2013

Thick InGaN Growth by Metal Organic Vapor Phase Epitaxy with Sputtered InGaN Buffer Layer Reviewed

Ohata, Toshiya, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JB11 2013

Amano, Hiroshi

Japanese Journal of Applied Physics Vol. 52 ( 5R ) page： 50001 - 050001-10 2013

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Applied Physics

Thin films of III--V compound semiconductors such as GaAs and InP can be grown on native substrates, whereas such growth was difficult for group III nitride semiconductors. Despite this drawback, scientists have gradually become able to use the functions of group III nitride semiconductors by growing their thin films on non-native substrates such as sapphire and Si substrates. With the continuously increasing demand for the conservation and generation of energy, bulk substrates of group III nitride semiconductors are highly expected to maximize their potential. In this report, I review the current status of the growth methods for bulk GaN single crystals used for substrates as well as summarize the characteristics of blue light-emitting diodes (LEDs), heterojunction field-effect transistors (HFETs), and photovoltaic cells on GaN substrates.

DOI： 10.7567/JJAP.52.050001

Stacking Faults and Luminescence Property of InGaN Nanowires Reviewed

Tabata, Takuya, Paek, Jihyun, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JE06 2013

Strain-Compensated Effect on the Growth of InGaN/AlGaN Multi-Quantum Well by Metalorganic Vapor Phase Epitaxy Reviewed

Doi, Tomohiro, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JB14 2013

Characteristics of a-plane GaN films grown on optimized silicon-dioxide-patterned r-plane sapphire substrates Reviewed

Son, Ji-Su, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi, Baik, Kwang Hyeon, Seo, Yong Gon, Hwang, Sung-Min

Thin Solid Films Vol. 546 page： 108-113 2013

High internal quantum efficiency blue-green light-emitting diode with small efficiency droop fabricated on low dislocation density GaN substrate Reviewed

Sano, Tomotaka, Doi, Tomohiro, Inada, Shunko Albano, Sugiyama, Tomohiko, Honda, Yoshio, Amano, Hiroshi, Yoshino, Takashi

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JK09 2013

Growth of GaN on Si (111) Substrates via a Reactive-Sputter-Deposited AlN Intermediate Layer Reviewed

Yamada, Takaya, Tanikawa, Tomoyuki, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JB16 2013

Growth mode and threading dislocation behavior of GaN films grown on patterned sapphire substrate with radial stripe pattern Reviewed

Okuno, Koji, Oshio, Takahide, Shibata, Naoki, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JB09 2013

GaN Nanowires Grown on a Graphite Substrate by Radio Frequency Molecular Beam Epitaxy Reviewed

Nakagawa, Shinta, Tabata, Takuya, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JE07 2013

Fabrication of InGaN/GaN Multiple Quantum Wells on (1bar 101) GaN Reviewed

Tanikawa, Tomoyuki, Sano, Tomotaka, Kushimoto, Maki, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JC05 2013

Effects of nano-and microscale SiO2 masks on the growth of a-plane GaN layers on r-plane sapphire Reviewed

Son, Ji-Su, Miao, Cao, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi, Seo, Yong Gon, Hwang, Sung-Min, Baik, Kwang Hyeon

Japanese Journal of Applied Physics Vol. 52 ( 8S ) page： 08JC04 2013

Effects of exciton localization on internal quantum efficiency of InGaN nanowires Reviewed

Murotani, Hideaki, Yamada, Yoichi, Tabata, Takuya, Honda, Yoshio, Yamaguchi, Masahito, Amano, Hiroshi

Journal of Applied Physics Vol. 114 ( 15 ) page： 153506 2013

Defects generation and annihilation in GaN grown on patterned silicon substrate

N. Sawaki, S. Ito, T. Nakagita, H. Iwata, T. Tanikawa, M. Irie, Y. Honda, M. Yamaguchi, H. Amano

GALLIUM NITRIDE MATERIALS AND DEVICES VIII Vol. 8625 page： 86250K-86250K-6 2013

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPIE-INT SOC OPTICAL ENGINEERING

The behavior of threading dislocations and stacking faults were investigated in a (1-101) GaN grown on a patterned (001)Si substrate by selective metal-organic-vapor-phase-epitaxy with an AlN buffer layer. Cross sectional transmission electron microscopy images showed that threading dislocations are generated at the hetero-interface of GaN/AlN/Si induced by misfit dislocations, while stacking faults are generated when two crystals with different crystal axes coalesce. We found some of them are annihilated making a loop, where two stacking faults have been generated at a short distance. This suggests a rout to decrease the density of stacking faults in III nitrides.

DOI： 10.1117/12.2002738

Polarization properties in InGaN/GaN multiple quantum well on semipolar (1-101)GaN/Si

Effects of low energy e-beam irradiation on cathodoluminescence from GaN Reviewed

S. Suihkonen, H. Nykänen, T. Tanikawa, M. Yamaguchi, Y. Honda, and H. Amano

phys. stat. sol. (a) Vol. 210 ( 2 ) page： 383-385 2012.12

Effects of low energy e-beam irradiation on cathodoluminescence from GaN Reviewed

S. Suihkonen, H. Nykänen, T. Tanikawa, M. Yamaguchi, Y. Honda, H. Amano

phys. stat. sol. (a) Vol. 210 ( 2 ) page： 383-385 2012.12

InGaNナノワイヤの内部量子効率に対する積層欠陥の影響

室谷英彰, 安藤浩哉, 塚本武彦, 杉浦藤虎, 山田陽一, 田畑拓也, 本田善央, 山口雅史, 天野浩

応用物理学会学術講演会講演予稿集 Vol. 2012.2 page： 3246 - 3246 2012.8

KUSHIMOTO Maki, TANIKAWA Tomoyuki, HONDA Yoshio, YAMAGUCHI Masahito, AMANO Hiroshi

IEICE technical report. Electron devices Vol. 112 ( 32 ) page： 15 - 18 2012.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Polarization properties in InGaN/GaN multiple quantum well on semipolar (1-101)GaN/Si

KUSHIMOTO Maki, TANIKAWA Tomoyuki, HONDA Yoshio, YAMAGUCHI Masahito, AMANO Hiroshi

Vol. 112 ( 33 ) page： 15 - 18 2012.5

Polarization properties in InGaN/GaN multiple quantum well on semipolar (1-101)GaN/Si

KUSHIMOTO Maki, TANIKAWA Tomoyuki, HONDA Yoshio, YAMAGUCHI Masahito, AMANO Hiroshi

Technical report of IEICE. SDM Vol. 112 ( 34 ) page： 15 - 18 2012.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Enhancement of two-dimensional electron gases in AlGaN-channel high-electron-mobility transistors with AlN barrier layers Reviewed

Strain relaxation in thick (1-101)InGaN grown on GaN/Si substrate Reviewed

T. Tanikawa, Y. Honda, M. Yamaguchi, H. Amano, and N. Sawaki

phys. stat. sol. (b) Vol. 249 ( 3 ) page： 468–471 2012.3

Strain relaxation in thick (1-101)InGaN grown on GaN/Si substrate Reviewed

T. Tanikawa, Y. Honda, M. Yamaguchi, H. Amano, N. Sawaki

phys. stat. sol. (b) Vol. 249 ( 3 ) page： 468–471 2012.3

Growth of InGaN nanowires on a (111)Si substrate by RF-MBE Reviewed

T. Tabata, J.H. Paek, Y. Honda, M. Yamaguchi, and H. Amano

phys. stat. sol. (c) Vol. 9 ( 3-4 ) page： 646–649 2012.3

Growth of InGaN nanowires on a (111)Si substrate by RF-MBE Reviewed

T. Tabata, J.H. Paek, Y. Honda, M. Yamaguchi, H. Amano

phys. stat. sol. (c) Vol. 9 ( 3-4 ) page： 646–649 2012.3

Small current collapse in AlGaN/GaN HFETs on a-plane GaN self-standing substrate Reviewed

T. Sugiyama, Y. Honda, M. Yamaguchi, H. Amano, Y. Isobe, M. Iwaya, T. Takeuchi, S. Kamiyama, I. Akasaki, M. Imade, Y. Kitaoka, and Y. Mori

phys. stat. sol. (c) Vol. 9 ( 3-4 ) page： 875–878 2012.3

In-situ void formation technique using an AlN shell structure grown on GaN stripes on Si(111) and c-plane sapphire substrates Reviewed

T. Mitsunari, T. Tanikawa, Y. Honda, M. Yamaguchi, and H. Amano

phys. stat. sol. (c) Vol. 9 ( 3-4 ) page： 480–483 2012.3

A local vibration mode in a carbon doped (1-101)AlGaN Reviewed

N. Sawaki, K. Hagiwara, K. Yamashita, N. Koide, Y. Honda, M. Yamaguchi, and H. Amano

SPIE Vol. 8262 page： 82620D 2012.3

In-situ void formation technique using an AlN shell structure grown on GaN stripes on Si(111) and c-plane sapphire substrates Reviewed

T. Mitsunari, T. Tanikawa, Y. Honda, M. Yamaguchi, H. Amano

phys. stat. sol. (c) Vol. 9 ( 3-4 ) page： 480–483 2012.3

Growth of InGaN nanowires on a (111)Si substrate by RF-MBE Reviewed

T. Tabata, J.H. Paek, Y. Honda, M. Yamaguchi, and H. Amano

phys. stat. sol. (c) Vol. 9 ( 3-4 ) page： 646–649 2012.3

Shin Hashimoto, Katsushi Akita, Yoshiyuki Yamamoto, Masaki Ueno, Takao Nakamura, Kenichiro Takeda, Motoaki Iwaya, Yoshio Honda, Hiroshi Amano

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE Vol. 209 ( 3 ) page： 501 - 504 2012.3

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

We have demonstrated a high sheet carrier concentration in AlGaN-channel high-electron-mobility transistors (HEMTs) with AlN barrier layer. We investigate the epitaxial structure of these HEMTs by X-ray diffraction and reveal that the partial lattice relaxation occurs in the Al0.51GaN-channel layers on the AlN buffer layers, and that the AlN barrier layer was coherently grown on the AlGaN channel layer. The sheet carrier concentration due to two-dimensional electron gases of the AlN/Al0.51GaN HEMT is 2.8 x 10(13) cm (2), which is enhanced owing to the use of AlN as the barrier layer. This value of the sheet carrier concentration agrees with the calculated value based on the model of partial lattice relaxation in AlGaN channel layer. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

DOI： 10.1002/pssa.201100379

Growth of InGaN nanowires on a (111)Si substrate by RF-MBE

T. Tabata, J.H. Paek, Y. Honda, M. Yamaguchi, H. Amano

phys. stat. sol. (c) Vol. 9 ( 3-4 ) page： 646–649 2012.3

InGaNナノワイヤにおける内部量子効率の発光波長依存性

室谷英彰, 安藤浩哉, 塚本武彦, 杉浦藤虎, 山田陽一, 田畑拓也, 本田善央, 山口雅史, 天野浩

応用物理学会学術講演会講演予稿集 Vol. 2012.1 page： 140 - 140 2012.2

Impurity incorporation in semipolar (1-101) GaN grown on an Si substrate Reviewed

N. Sawaki, K. Hagiwara, T. Hikosaka, and Y. Honda

Semicond. Sci. Technol. Vol. 27 page： 024006_1-024006_5 2012.1

Impurity incorporation in semipolar (1-101) GaN grown on an Si substrate Reviewed

N. Sawaki, K. Hagiwara, T. Hikosaka, Y. Honda

Semicond. Sci. Technol. Vol. 27 page： 024006_1-024006_5 2012.1

Growth of InGaN nanowires on a (111)Si substrate by RF-MBE Reviewed

Tabata Takuya, Paek Jihyun, Honda Yoshio, Yamaguchi Masahito, Amano Hiroshi

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 9, NO 3-4 Vol. 9 ( 3-4 ) page： 646 - 649 2012

In-situ void formation technique using an AlN shell structure grown on GaN stripes on Si(111) and c-plane sapphire substrates Reviewed

Mitsunari Tadashi, Tanikawa Tomoyuki, Honda Yoshio, Yamaguchi Masahito, Amano Hiroshi

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 9, NO 3-4 Vol. 9 ( 3-4 ) page： 480 - 483 2012

Small current collapse in AlGaN/GaN HFETs on a-plane GaN self-standing substrate Reviewed

T. Sugiyama, Y. Honda, M. Yamaguchi, H. Amano, Y. Isobe, M. Iwaya, T. Takeuchi, S. Kamiyama, I. Akasaki, M. Imade, Y. Kitaoka, Y. Mori

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 9, NO 3-4 Vol. 9 ( 3-4 ) page： 875 - 878 2012

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-V C H VERLAG GMBH

We measured drain bias stress effects and current collapse in AlGaN/GaN heterostructure field-effect transistors (HFETs) on a-plane and c-plane GaN substrates. An a-plane AlGaN/GaN HFET (a-HFET) shows small current collapse with a threshold voltage (V-th=-1.8 V). On the other hand, a c-plane HFET (c-HFET) with the same barrier thickness (20 nm) shows a small current collapse, although V-th was negatively large (V-th=-4 V). Current collapse in a-HFET was not large compared with that in conventional c-HFET on GaN. A c-HFET on sapphire was also measured. The current collapses in HFETs on sapphire were larger than that in HFETs on a GaN substrate. The current collapses in the thin-barrier c-HFET (Vth=-1.8 V) were particularly large. Therefore, an a-plane device is promising for a small or positive Vth with small current collapse. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

DOI： 10.1002/pssc.201100397

A local vibration mode in a carbon doped (1-101)AlGaN

N. Sawaki, K. Hagiwara, K. Yamashita, N. Koide, Y. Honda, M. Yamaguchi, H. Amano

GALLIUM NITRIDE MATERIALS AND DEVICES VII Vol. 8262 page： 82620D 2012

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPIE-INT SOC OPTICAL ENGINEERING

Behavior of carbon (C) doping in a (1-101)AlGaN has been investigated by grazing incidence FTIR analyses at room temperature. The sample was grown by MOVPE on (1-101) facets of GaN triangular stripes made on (111) Si substrate. Intentional C doping was performed by introducing C2H2 into the reactor during the growth. In the FTIR spectra, a C related LVM mode was found out at 950 cm(-1) which was associated with A(1)(LO) mode of AlN at 890cm-1. The behavior was similar to the results found in an un-intentionally Al doped GaN sample. Linear chain model with an effective mass gives the LVM energy of Al-C bond at 930 cm(-1), a little lower than the experimental observation. The C doping on the N site might be performed forming a complex with additional elements.

DOI： 10.1117/12.905529

AlGaN-Based Deep Ultraviolet Light-Emitting Diodes Fabricated on Patterned Sapphire Substrates Reviewed

Improvement of Light Extraction Efficiency for AlGaN-Based Deep Ultraviolet Light-Emitting Diodes Reviewed

T. Inazu, S. Fukahori, C. Pernot, M. H. Kim, T. Fujita, Y. Nagasawa, A. Hirano, M. Ippommatsu, M. Iwaya, T. Takeuchi, S. Kamiyama, M. Yamaguchi, Y. Honda, H. Amano, and I. Akasaki

Jpn. J. Appl. Phys. Vol. 50 ( 12 ) page： 122101_1-122101_3 2011.12

Improvement of Light Extraction Efficiency for AlGaN-Based Deep Ultraviolet Light-Emitting Diodes Reviewed

T. Inazu, S. Fukahori, C. Pernot, M. H. Kim, T. Fujita, Y. Nagasawa, A. Hirano, M. Ippommatsu, M. Iwaya, T. Takeuchi, S. Kamiyama, M. Yamaguchi, Y. Honda, H. Amano, I. Akasaki

Jpn. J. Appl. Phys. Vol. 50 ( 12 ) page： 122101_1-122101_3 2011.12

Raman Spectroscopic Study Of Residual Strain In (1-101) GaN And (0001) GaN Layers Grown On Si Substrate Reviewed

T. Sugiura, E.H. Kim, Y. Honda, H. Takagi, T. Tsukamoto, H. Andoh, M. Yamaguchi, and N. Sawaki

AIP Conf. Proc. Vol. 1399 page： 503-504 2011.12

Raman Spectroscopic Study Of Residual Strain In (1-101) GaN And (0001) GaN Layers Grown On Si Substrate Reviewed

T. Sugiura, E.H. Kim, Y. Honda, H. Takagi, T. Tsukamoto, H. Andoh, M. Yamaguchi, and N. Sawaki

AIP Conf. Proc. Vol. 1399 page： 503-504 2011.12

Raman Spectroscopic Study Of Residual Strain In (1-101) GaN And (0001) GaN Layers Grown On Si Substrate Reviewed

T. Sugiura, E.H. Kim, Y. Honda, H. Takagi, T. Tsukamoto, H. Andoh, M. Yamaguchi, N. Sawaki

AIP Conf. Proc. Vol. 1399 page： 503-504 2011.12

Raman Spectroscopic Study Of Residual Strain In (1-101) GaN And (0001) GaN Layers Grown On Si Substrate Reviewed

T. Sugiura, E.H. Kim, Y. Honda, H. Takagi, T. Tsukamoto, H. Andoh, M. Yamaguchi, N. Sawaki

AIP Conf. Proc. Vol. 1399 page： 503-504 2011.12

Kim Myunghee, Fujita Takehiko, Fukahori Shinya, INAZU Tetsuhiko, PERNOT Cyril, NAGASAWA Yosuke, HIRANO Akira, IPPOMMATSU Masamichi, IWAYA Motoaki, TAKEUCHI Tetsuya, KAMIYAMA Satoshi, YAMAGUCHI Masahito, HONDA Yoshio, AMANO Hiroshi, AKASAKI Isamu

Applied physics express Vol. 4 ( 9 ) page： "092102 - 1"-"092102-3" 2011.9

AlGaN-Based Deep Ultraviolet Light-Emitting Diodes Fabricated on Patterned Sapphire Substrates Reviewed

M.H. Kim, T. Fujita, S. Fukahori, T. Inazu, C. Pernot, Y. Nagasawa, A. Hirano, M. Ippommatsu, M. Iwaya, T. Takeuchi, S. Kamiyama, M. Yamaguchi, Y. Honda, H. Amano, and I. Akasaki

Appl. Phys. Express Vol. 4 ( 9 ) page： 092102_1-092102_3 2011.8

AlGaN-Based Deep Ultraviolet Light-Emitting Diodes Fabricated on Patterned Sapphire Substrates Reviewed

M.H. Kim, T. Fujita, S. Fukahori, T. Inazu, C. Pernot, Y. Nagasawa, A. Hirano, M. Ippommatsu, M. Iwaya, T. Takeuchi, S. Kamiyama, M. Yamaguchi, Y. Honda, H. Amano, and I. Akasaki

Appl. Phys. Express Vol. 4 ( 9 ) page： 092102_1-092102_3 2011.8

AlGaN-Based Deep Ultraviolet Light-Emitting Diodes Fabricated on Patterned Sapphire Substrates Reviewed

M.H. Kim, T. Fujita, S. Fukahori, T. Inazu, C. Pernot, Y. Nagasawa, A. Hirano, M. Ippommatsu, M. Iwaya, T. Takeuchi, S. Kamiyama, M. Yamaguchi, Y. Honda, H. Amano, I. Akasaki

Appl. Phys. Express Vol. 4 ( 9 ) page： 092102_1-092102_3 2011.8

AlGaN-Based Deep Ultraviolet Light-Emitting Diodes Fabricated on Patterned Sapphire Substrates Reviewed

M.H. Kim, T. Fujita, S. Fukahori, T. Inazu, C. Pernot, Y. Nagasawa, A. Hirano, M. Ippommatsu, M. Iwaya, T. Takeuchi, S. Kamiyama, M. Yamaguchi, Y. Honda, H. Amano, I. Akasaki

Appl. Phys. Express Vol. 4 ( 9 ) page： 092102_1-092102_3 2011.8

(1-101)GaN/Si上InGaN厚膜のMOVPE成長

TANIKAWA Tomoyuki, HONDA Yoshio, YAMAGUCHI Masahito, AMANO Hiroshi, SAWAKI Nobuhiko

IEICE technical report Vol. 111 ( 44 ) page： 63 - 66 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

We demonstrated thick InGaN growth on (1-101)GaN/Si. The grown samples had relative smooth surface with RMS value of less than 10nm. From X-ray reciprocal space mapping, InGaN layer showed incoherent growth. First, the lattice relaxation occurred by generation of misfit dislocations between InGaN/GaN interface and inclined along <0001> projection. At a high indium content, a high density of misfit dislocations was generated, resulted in a larger inclination. Along <11-20> direction, InGaN lattice relaxation only occurred along the in-plane direction.

GaN系HFETsの電流コラプスの測定 : 非極性a面GaN基板上HFET及びc-GaN基板上p-GaNゲートを用いたノーマリーオフ型JHFET

SUGIYAMA T., HONDA Y., YAMAGUCHI M., AMANO H., ISOBE Y., OSHIMURA Y., IWAYA M., TAKEUCHI T., KAMIYAMA S., AKASAKI I., IMADE M., KITAOKA Y., MORI Y.

IEICE technical report Vol. 111 ( 45 ) page： 175 - 178 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

We measured current collapse in AlGaN/GaN HFETs on an a-plane GaN substrate. Non polar HFETs are promising for realizing a high V_<th> and a small current collapse than c-plane HFETs. We also measured current collapse in normally off mode AlGaN/GaN JHFETs with a p-GaN gate. The large current collapse was observed in unpassivated sample, because AlGaN barrier of JHFETs was exposed to air by dry etching. On the other hand current collapse in the SiNx-passivated JHFETs is small and almost the same as that in as-grown HFETs.

GaN系HFETsの電流コラプスの測定 : 非極性a面GaN基板上HFET及びc-GaN基板上p-GaNゲートを用いたノーマリーオフ型JHFET

杉山貴之, 本田善央, 山口雅史, 天野浩, 磯部康裕, 押村吉徳, 岩谷素顕, 竹内哲也, 上山智, 赤崎勇, 今出完, 北岡康夫, 森勇介

電子情報通信学会技術研究報告. ED, 電子デバイス Vol. 111 ( 44 ) page： 175 - 178 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

c面および非極性a面GaN基板上AlGaN/GaN HFETの電流コラプスを測定した。a-HFETはc面上のHFETsに比べ高い閾値電圧と電流コラプス耐性の両立に優れることを実証した。また、p-GaNゲートを用いたc面ノーマリーオフ型JHFETについても電流コラプスの測定を行った、ドライエッチングによって露出されたAlGaN表面のデバイスでは電流コラプスが極めて大きいが、SiNパッシベーションによって、as-grownで同じ組成・膜厚を有するAlGaNバリアのノーマリーオフ型HFETsと同程度まで電流コラプス耐性が向上した。

AlGaN系紫外発光素子の通電特性 : UV-LEDの劣化メカニズム

朴貴珍, 杉山貴之, 谷川智之, 本田善央, 山口雅史, 天野浩, 稲津哲彦, 藤田武彦, ペルノーシリル, 平野光

電子情報通信学会技術研究報告. SDM, シリコン材料・デバイス Vol. 111 ( 46 ) page： 123 - 126 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

長時間・大電流駆動によるAlGaN系紫外発光素子の通電特性の変化から発光効率とリーク電流成分の増大の関連性、また、発光層への注入効率とリーク成分の関係性を調べた.劣化初期、通電時間が経つとともにリーク電流は増大、IQEは一定であった.しかし、駆動時間400時間目の結果からIQEの低下が観測された.その原因はリーク電流によるジュール熱であると考えられる.

AlGaN系紫外発光素子の通電特性 : UV-LEDの劣化メカニズム

朴貴珍, 杉山貴之, 谷川智之, 本田善央, 山口雅史, 天野浩, 稲津哲彦, 藤田武彦, ペルノーシリル, 平野光

電子情報通信学会技術研究報告. CPM, 電子部品・材料 Vol. 111 ( 45 ) page： 123 - 126 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

AlGaN系紫外発光素子の通電特性 : UV-LEDの劣化メカニズム

朴貴珍, 杉山貴之, 谷川智之, 本田善央, 山口雅史, 天野浩, 稲津哲彦, 藤田武彦, ペルノーシリル, 平野光

電子情報通信学会技術研究報告. ED, 電子デバイス Vol. 111 ( 44 ) page： 123 - 126 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

(1-101)GaN/Si上InGaN厚膜のMOVPE成長

谷川智之, 本田善央, 山口雅史, 天野浩, 澤木宣彦

電子情報通信学会技術研究報告. SDM, シリコン材料・デバイス Vol. 111 ( 46 ) page： 63 - 66 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

MOVPE法により(1-101)GaN/Si上にInGaN厚膜の成長を試みた。InGaNを成長するとGaNにみられた原子ステップは消失し、三次元成長が促進されていることを確認したが、c面によくみられるV字ピットは現れず、10nm以下の平均粗さを有する平坦性の比較的優れた結晶であることが分かった。X線逆格子マッピング測定よりInGaN結晶の格子緩和過程を観察すると、2段階の緩和過程が観察された。低In組成ではコヒーレント成長していたのに対し、In組成が増大するにつれまずc軸方向へのチルトが見られた。これは格子不整合により界面にミスフィット転位が導入されることに起因すると思われる。In組成が高くなるについてミスフィット転位の間隔が狭くなりチルト角度が増大した。<11-20>方向においては面内の格子緩和のみ発生した。

(1-101)GaN/Si上InGaN厚膜のMOVPE成長

谷川智之, 本田善央, 山口雅史, 天野浩, 澤木宣彦

電子情報通信学会技術研究報告. CPM, 電子部品・材料 Vol. 111 ( 45 ) page： 63 - 66 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

GaN系HFETsの電流コラプスの測定 : 非極性a面GaN基板上HFET及びc-GaN基板上p-GaNゲートを用いたノーマリーオフ型JHFET

SUGIYAMA T., HONDA Y., YAMAGUCHI M., AMANO H., ISOBE Y., OSHIMURA Y., IWAYA M., TAKEUCHI T., KAMIYAMA S., AKASAKI I., IMADE M., KITAOKA Y., MORI Y.

IEICE technical report Vol. 111 ( 46 ) page： 175 - 178 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

RF-MBE法による(111)Si基板上へのInGaNナノワイヤ成長

田畑拓也, 白知鉉, 本田善央, 山口雅史, 天野浩

電子情報通信学会技術研究報告. SDM, シリコン材料・デバイス Vol. 111 ( 46 ) page： 45 - 48 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

従来のプレーナ型量子井戸構造と比較してInGaNナノワイヤは可視光長波長領域において、より優れた発光特性を示すと予想される。本研究では、RF-MBE法により(111)Si基板上にIn/(In+Ga)フラックス比および成長温度を変化させてInGaNナノワイヤの成長を行った。成長温度を固定した場合、Inフラックス比が大きくなるほどナノワイヤにおけるIn組成の増大とともにフォトルミネッセンス(PL)ピーク波長は長波長側へシフトした。また、成長温度が高くなるにつれて、PLピーク波長は短波長側へシフトし、PL強度は大きくなった。これは成長温度が高くなるにつれてInの脱離が多くなったこと、およびInGaNナノワイヤの結晶性が向上したことが原因として考えられる。しかし、PLスペクトルの温度依存性からInGaNナノワイヤの内部量子効率を見積もると18%程度であった。これはSTEM像において確認された積層欠陥が原因の1つに挙げられる。

RF-MBE法による(111)Si基板上へのInGaNナノワイヤ成長

田畑拓也, 白知鉉, 本田善央, 山口雅史, 天野浩

電子情報通信学会技術研究報告. ED, 電子デバイス Vol. 111 ( 44 ) page： 45 - 48 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

RF-MBE法による(111)Si基板上へのInGaNナノワイヤ成長

田畑拓也, 白知鉉, 本田善央, 山口雅史, 天野浩

電子情報通信学会技術研究報告. CPM, 電子部品・材料 Vol. 111 ( 45 ) page： 45 - 48 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

Effect of lateral vapor-phase diffusion during the selective growth of InGaN/GaN MQW on semi-polar and non-polar GaN stripes Reviewed

T. Tanikawa, Y. Honda, M. Yamaguchi, and H. Amano

phys. stat. sol. (a) Vol. 208 ( 5 ) page： 1175-1178 2011.5

Optical properties of (1-101)semi-polar InGaN/GaN multiple quantum wells grown on patterned silicon substrates Reviewed

C.H. Chiu, D.W. Lin, C.C. Lin, Z.Y. Li, Y.C. Chen, S.C. Ling, H.C. Kuo, T.C. Lu, S.C. Wang, W.T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 318 ( 1 ) page： 500-504 2011.5

Effect of lateral vapor-phase diffusion during the selective growth of InGaN/GaN MQW on semi-polar and non-polar GaN stripes Reviewed

T. Tanikawa, Y. Honda, M. Yamaguchi, and H. Amano

phys. stat. sol. (a) Vol. 208 ( 5 ) page： 1175-1178 2011.5

Optical properties of (1-101)semi-polar InGaN/GaN multiple quantum wells grown on patterned silicon substrates Reviewed

C.H. Chiu, D.W. Lin, C.C. Lin, Z.Y. Li, Y.C. Chen, S.C. Ling, H.C. Kuo, T.C. Lu, S.C. Wang, W.T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

J. Cryst. Growth Vol. 318 ( 1 ) page： 500-504 2011.5

Effect of lateral vapor-phase diffusion during the selective growth of InGaN/GaN MQW on semi-polar and non-polar GaN stripes Reviewed

T. Tanikawa, Y. Honda, M. Yamaguchi, H. Amano

phys. stat. sol. (a) Vol. 208 ( 5 ) page： 1175-1178 2011.5

Effect of lateral vapor-phase diffusion during the selective growth of InGaN/GaN MQW on semi-polar and non-polar GaN stripes Reviewed

T. Tanikawa, Y. Honda, M. Yamaguchi, H. Amano

phys. stat. sol. (a) Vol. 208 ( 5 ) page： 1175-1178 2011.5

Spontaneous formation of highly regular superlattice structure in InGaN epilayers grown by molecular beam epitaxy Reviewed

Z. H. Wu, Y. Kawai, Y.-Y. Fang, C. Q. Chen, H. Kondo, M. Hori, Y. Honda, M. Yamaguchi, and H. Amano

Appl. Phys. Lett. Vol. 98 ( 14 ) page： 141905 2011.4

Semi-polar GaN LEDs on Si substrate Reviewed

N. Sawaki and Y. Honda

SCIENCE CHINA Technological Sciences Vol. 54 ( 1 ) page： 38-41 2011.4

Spontaneous formation of highly regular superlattice structure in InGaN epilayers grown by molecular beam epitaxy Reviewed

Z. H. Wu, Y. Kawai, Y.-Y. Fang, C. Q. Chen, H. Kondo, M. Hori, Y. Honda, M. Yamaguchi, and H. Amano

Appl. Phys. Lett. Vol. 98 ( 14 ) page： 141905 2011.4

Spontaneous formation of highly regular superlattice structure in InGaN epilayers grown by molecular beam epitaxy Reviewed

Z. H. Wu, Y. Kawai, Y. -Y. Fang, C. Q. Chen, H. Kondo, M. Hori, Y. Honda, M. Yamaguchi, H. Amano

APPLIED PHYSICS LETTERS Vol. 98 ( 14 ) page： 141905 2011.4

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

In this letter, we have investigated the structural properties of thick InGaN layers grown on GaN by plasma-assisted molecular beam epitaxy, using two growth rates of 1.0 and 3.6 angstrom/s. A highly regular superlattice (SL) structure is found to be spontaneously formed in the film grown at 3.6 angstrom/s but not in the film grown at 1.0 angstrom/s. The faster grown film also exhibits superior structural quality, which could be due to the surface roughness suppression caused by kinetic limitation, and the inhibition of the Frank-Read dislocation generation mechanism within the spontaneously formed SL structure. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3574607]

DOI： 10.1063/1.3574607

Reduction of Efficiency Droop in Semipolar (1(1)over-bar01) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates (vol 4, 012105, 2011) Open Access

Semi-polar GaN LEDs on Si substrate Reviewed

N. Sawaki, Y. Honda

SCIENCE CHINA Technological Sciences Vol. 54 ( 1 ) page： 38-41 2011.4

Spontaneous formation of highly regular superlattice structure in InGaN epilayers grown by molecular beam epitaxy Reviewed

Z. H. Wu, Y. Kawai, Y.-Y. Fang, C. Q. Chen, H. Kondo, M. Hori, Y. Honda, M. Yamaguchi, H. Amano

Appl. Phys. Lett. Vol. 98 ( 14 ) page： 141905 2011.4

Optical properties of (1-101)semi-polar InGaN/GaN multiple quantum wells grown on patterned silicon substrates Reviewed

C.H. Chiu, D.W. Lin, C.C. Lin, Z.Y. Li, Y.C. Chen, S.C. Ling, H.C. Kuo, T.C. Lu, S.C. Wang, W.T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 318 ( 1 ) page： 500-504 2011.3

Optical properties of (1-101)semi-polar InGaN/GaN multiple quantum wells grown on patterned silicon substrates Reviewed

C.H. Chiu, D.W. Lin, C.C. Lin, Z.Y. Li, Y.C. Chen, S.C. Ling, H.C. Kuo, T.C. Lu, S.C. Wang, W.T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

J. Cryst. Growth Vol. 318 ( 1 ) page： 500-504 2011.3

Growth of semi-polar GaN-based light-emitting diodes grown on an patterned Si substrate Reviewed

C.H. Chiu, D.W. Lin, Z.Y. Li, S.C. Ling, H.C. Kuo, T.C. Lu, S.C. Wang, W.T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, and N. Sawaki

SPIE Vol. 7939 page： 79391X 2011.3

Growth of semi-polar GaN-based light-emitting diodes grown on an patterned Si substrate Reviewed

C.H. Chiu, D.W. Lin, Z.Y. Li, S.C. Ling, H.C. Kuo, T.C. Lu, S.C. Wang, W.T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, and N. Sawaki

SPIE Vol. 7939 page： 79391X 2011.3

Ching-Hsueh Chiu, Da-Wei Lin, Chien-Chung Lin, Zhen-Yu Li, Wei-Ting Chang, Hung-Wen Hsu, Hao-Chung Kuo, Tien-Chang Lu, Shing-Chung Wang, Wei-Tsai Liao, Tomoyuki Tanikawa, Yoshio Honda, Masahito Yamaguchi, Nobuhiko Sawaki

APPLIED PHYSICS EXPRESS Vol. 4 ( 3 ) 2011.3

Growth of semi-polar GaN-based light-emitting diodes grown on an patterned Si substrate Reviewed

C.H. Chiu, D.W. Lin, Z.Y. Li, S.C. Ling, H.C. Kuo, T.C. Lu, S.C. Wang, W.T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

SPIE Vol. 7939 page： 79391X 2011.3

Photonic properties of erbium doped InGaN alloys grown on Si (001) substrates Reviewed

I. W. Feng, X. K. Cao, J. Li, J. Y. Lin, H. X. Jiang, N. Sawaki, Y. Honda, T. Tanikawa, J. M. Zavada

APPLIED PHYSICS LETTERS Vol. 98 ( 8 ) 2011.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

Erbium doped InGaN alloys (InGaN:Er) were grown on Si (001) substrates using metal organic chemical vapor deposition. The growth of epitaxial films was accomplished by depositing InGaN:Er on GaN templates deposited on 7.3 degrees off-oriented Si (001) substrates which were prepared by etching and subsequent selective area growth. X-ray diffraction measurements confirmed the formation of wurtzite InGaN (1 (1) over bar 01) epilayers, which exhibit strong photoluminescence emission at 1.54 mu m. The observed emission intensity at 1.54 mu m was comparable to that from similar alloys grown on GaN/AlN/Al(2)O(3) templates. These results indicate the high potential for on-chip integration of erbium based photonic devices with complementary metal oxide semiconductor technology. (C) 2011 American Institute of Physics. [doi:10.1063/1.3556678]

DOI： 10.1063/1.3556678

Reduction of Efficiency Droop in Semipolar (1101) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates

Chiu Ching-Hsueh, Lin Da-Wei, Lin Chien-Chung, LI Zhen-Yu, CHANG Wei-Ting, HSU Hung-Wen, KUO Hao-Chung, LU Tien-Chang, WANG Shing-Chung, LIAO Wei-Tsai, TANIKAWA Tomoyuki, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

Applied physics express Vol. 4 ( 1 ) page： "012105 - 1"-"012105-3" 2011.1

Semi-polar GaN LEDs on Si substrate Reviewed

N. Sawaki and Y. Honda

SCIENCE CHINA Technological Sciences Vol. 54 ( 1 ) page： 38-41 2011.1

Semi-polar GaN LEDs on Si substrate Reviewed

N. Sawaki, Y. Honda

SCIENCE CHINA Technological Sciences Vol. 54 ( 1 ) page： 38-41 2011.1

Reduction of Efficiency Droop in Semipolar (1-101) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates Reviewed

C.-H. Chiu, D.-W. Lin, C.-C. Lin, Z.-Y. Li, W.-T. Chang, H.-W. Hsu, H.-C. Kuo, T.-C. Lu, S.-C. Wang, W.-T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, and N. Sawaki

Appl. Phys. Express Vol. 4 ( 1 ) page： 01210_1-012105_3 2011.1

Drastic Reduction of Dislocation Density in Semipolar (11-22) GaN Stripe Crystal on Si Substrate by Dual Selective Metal-Organic Vapor Phase Epitaxy Reviewed

T. Murase, T. Tanikawa, Y. Honda, M. Yamaguchi, H. Amano, and N. Sawaki

Jpn. J. Appl. Phys. Vol. 50 ( 1 ) page： 01AD04_1-01AD04_3 2011.1

Drastic Reduction of Dislocation Density in Semipolar (11-22) GaN Stripe Crystal on Si Substrate by Dual Selective Metal-Organic Vapor Phase Epitaxy Reviewed

T. Murase, T. Tanikawa, Y. Honda, M. Yamaguchi, H. Amano, N. Sawaki

Jpn. J. Appl. Phys. Vol. 50 ( 1 ) page： 01AD04_1-01AD04_3 2011.1

Reduction of Efficiency Droop in Semipolar (1-101) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates Reviewed

C.-H. Chiu, D.-W. Lin, C.-C. Lin, Z.-Y. Li, W.-T. Chang, H.-W. Hsu, H.-C. Kuo, T.-C. Lu, S.-C. Wang, W.-T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, and N. Sawaki

Appl. Phys. Express Vol. 4 ( 1 ) page： 01210_1-012105_3 2011.1

Partial strain relaxation by stacking fault generation in InGaN multiple quantum wells grown on (11-01) semipolar GaN Reviewed

Z. H. Wu, T. Tanikawa, T. Murase, Y.-Y. Fang, C. Q. Chen, Y. Honda, M. Yamaguchi, H. Amano, and N. Sawaki

Appl. Phys. Lett. Vol. 98 ( 5 ) page： 051902_1-051902_3 2011.1

Drastic Reduction of Dislocation Density in Semipolar (11-22) GaN Stripe Crystal on Si Substrate by Dual Selective Metal-Organic Vapor Phase Epitaxy Reviewed

T. Murase, T. Tanikawa, Y. Honda, M. Yamaguchi, H. Amano, and N. Sawaki

Jpn. J. Appl. Phys. Vol. 50 ( 1 ) page： 01AD04_1-01AD04_3 2011.1

Partial strain relaxation by stacking fault generation in InGaN multiple quantum wells grown on (11-01) semipolar GaN Reviewed

Z. H. Wu, T. Tanikawa, T. Murase, Y.-Y. Fang, C. Q. Chen, Y. Honda, M. Yamaguchi, H. Amano, and N. Sawaki

Appl. Phys. Lett. Vol. 98 ( 5 ) page： 051902_1-051902_3 2011.1

Reduction of Efficiency Droop in Semipolar (1-101) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates Reviewed

C.-H. Chiu, D.-W. Lin, C.-C. Lin, Z.-Y. Li, W.-T. Chang, H.-W. Hsu, H.-C. Kuo, T.-C. Lu, S.-C. Wang, W.-T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

Appl. Phys. Express Vol. 4 ( 1 ) page： 01210_1-012105_3 2011.1

Partial strain relaxation by stacking fault generation in InGaN multiple quantum wells grown on (11-01) semipolar GaN Reviewed

Z. H. Wu, T. Tanikawa, T. Murase, Y.-Y. Fang, C. Q. Chen, Y. Honda, M. Yamaguchi, H. Amano, N. Sawaki

Appl. Phys. Lett. Vol. 98 ( 5 ) page： 051902_1-051902_3 2011.1

Partial strain relaxation by stacking fault generation in InGaN multiple quantum wells grown on (1(1)over-bar01) semipolar GaN Reviewed

Z. H. Wu, T. Tanikawa, T. Murase, Y. -Y. Fang, C. Q. Chen, Y. Honda, M. Yamaguchi, H. Amano, N. Sawaki

APPLIED PHYSICS LETTERS Vol. 98 ( 5 ) page： 051902_1-051902_3 2011.1

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

We have investigated the structural properties and relaxation phenomenon of InGaN multiple quantum wells (QWs) on (1 (1) over bar 01) semipolar GaN templates grown on patterned (001) silicon substrates by selective area growth technique. Our studies by transmission electron microscopy and x-ray diffraction reciprocal space mapping reveal that QWs emitting light at 540 nm experience significant strain relaxation along the in-plane [1 (1) over bar0 (2) over bar] direction by the generation of an array of basal stacking faults (BSF). The generation of BSFs in 540 nm QWs could be an important factor limiting its luminescence efficiency. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3549561]

DOI： 10.1063/1.3549561

Drastic Reduction of Dislocation Density in Semipolar (11-22) GaN Stripe Crystal on Si Substrate by Dual Selective Metal-Organic Vapor Phase Epitaxy Reviewed

T. Murase, T. Tanikawa, Y. Honda, M. Yamaguchi, H. Amano, N. Sawaki

Jpn. J. Appl. Phys. Vol. 50 ( 1 ) page： 01AD04_1-01AD04_3 2011.1

Drain bias stress and memory effects in AlGaN/GaN heterostructure field-effect transistors with p-GaN gate Reviewed

Sugiyama Takayuki, Honda Yoshio, Yamaguchi Masahito, Amano Hiroshi, Oshimura Yoshinori, Iida Daisuke, Iwaya Motoaki, Akasaki Isamu

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 8, NO 7-8 Vol. 8 ( 7-8 ) 2011

Optical properties of (1-101) InGaN/GaN MQW stripe laser structure on Si substrate Reviewed

Murase Tasuku, Tanikawa Tomoyuki, Honda Yoshio, Yamaguchi Masahito, Amano Hiroshi

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 8, NO 7-8 Vol. 8 ( 7-8 ) 2011

Selective MOVPE growth of InGaN/GaN MQW on microfacet GaN stripes Reviewed

Tanikawa Tomoyuki, Murase Tasuku, Honda Yoshio, Yamaguchi Masahito, Amano Hiroshi

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 8, NO 7-8 Vol. 8 ( 7-8 ) 2011

Reduction of Efficiency Droop in Semipolar (1(1)over-bar01) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates Reviewed

C. H. Chiu, D. W. Lin, C. C. Lin, Z. Y. Li, H. C. Kuo, T. C. Lu, S. C. Wang, W. T. Liao, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

2011 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) Vol. 4 ( 1 ) page： 01210_1-012105_3 2011

Language：English Publishing type：Research paper (international conference proceedings) Publisher：IEEE

The semi-polar InGaN-based LEDs exhibits low efficiency droop because the reduction of the polarization field not only made the band diagram smoother but also restricted electron overflow to the p-GaN layer as shown in simulations. (C) 2010 Optical Society of America

Growth of semi-polar GaN-based light-emitting diodes grown on an patterned Si substrate Reviewed

Ching-Hsueh Chiu, Da-Wei Lin, Zhen-Yu Li, Shih-Chun Ling, Hao-Chung Kuo, Tien-Chang Lu, Shing-Chung Wang, Wei-Tasi Liao, Tomoyuki Tanikawa, Yoshio Honda, Masahito Yamaguchi, Nobuhiko Sawaki

GALLIUM NITRIDE MATERIALS AND DEVICES VI Vol. 7939 page： 79391X 2011

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPIE-INT SOC OPTICAL ENGINEERING

We present a study of semi-polar (1 (1) over bar 01) InGaN-based light emitting diodes (LEDs) grown on patterned (001) Si substrates by atmospheric-pressure metal organic chemical vapor deposition. A transmission electron microscopy image of the semi-polar template shows that the threading dislocation density was decreased significantly. From electroluminescence measurement, semi-polar LEDs exhibit little blue-shift and low efficiency droop at a high injection current because the reduction of the polarization field not only made the band diagram smoother but also restricted electron overflow to the p-GaN layer as shown in simulations. These results indicate that semi-polar InGaN-based LEDs can possess a high radiative recombination rate and low efficiency droop at a high injection current.

DOI： 10.1117/12.876656

IQE and EQE of the nitride-based UV/DUV LEDs Reviewed

H. Amano, G. J. Park, T. Tanikawa, Y. Honda, M. Yamaguchi, K. Ban, K. Nagata, K. Nonaka, K. Takeda, M. Iwaya, T. Takeuchi, S. Kamiyama, I. Akasaki

2011 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) 2011

Language：English Publishing type：Research paper (international conference proceedings) Publisher：IEEE

Internal and external quantum efficiency and injection efficiency of nitride-based UV/DUV devices were investigated. Non radiative component in the photoluminescence and electroluminescence is found to be strongly correlated with the dislocation density.

選択MOVPE法を用いた極性・非極性GaNストライプ上へのInGaN/GaN MQW構造の作製 Reviewed

Fabrication of InGaN/GaN stripe structure on (111)Si and stimulated emission under photo-excitation Reviewed

B.-J. Kim, T. Tanikawa, Y. Honda, M. Yamaguchi, and N. Sawaki

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 8, NO 7-8 Vol. 42 ( 10 ) page： 2575-2578 2010.10

Fabrication of InGaN/GaN stripe structure on (111)Si and stimulated emission under photo-excitation Reviewed

B.-J. Kim, T. Tanikawa, Y. Honda, M. Yamaguchi, and N. Sawaki

Physica E Vol. 42 ( 10 ) page： 2575-2578 2010.10

Fabrication of InGaN/GaN stripe structure on (111)Si and stimulated emission under photo-excitation Reviewed

B.-J. Kim, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

Physica E Vol. 42 ( 10 ) page： 2575-2578 2010.10

Fabrication of InGaN/GaN stripe structure on (111)Si and stimulated emission under photo-excitation Reviewed

B.-J. Kim, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

Physica E Vol. 42 ( 10 ) page： 2575-2578 2010.10

HVPE growth of a -plane GaN on a GaN template (110)Si substrate Reviewed

T. Tanikawa, N. Suzuki, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 7 ( 7-8 ) page： 1760–1763 2010.7

HVPE growth of a -plane GaN on a GaN template (110)Si substrate Reviewed

T. Tanikawa, N. Suzuki, Y. Honda, M. Yamaguchi, N. Sawaki

phys. stat. sol. (c) Vol. 7 ( 7-8 ) page： 1760–1763 2010.7

TANIKAWA Tomoyuki, HONDA Yoshio, YAMAGUCHI Masahito

IEICE technical report Vol. 109 ( 422 ) page： 23 - 28 2010.2

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

We investigated the InGaN/GaN multiple quantum well(MQW)thickness and luminescence distribution on non c-plane GaN stripes. In the case of non-polar crystal, InGaN MQW at the edge region was thicker than the center region. On the other hand, we got uniform thickness on semi-polar crystals. We simulated the diffusion process in gas phase and estimated the diffusion length of chemical species on each facets. The estimated results suggested that the non-uniformity of thickness was attributed to the chemical source diffusion from vapor phase. While CL spectra showed broad InGaN peak, there were no difference between the center and edge region. We concluded that non-uniformity of thickness and/or composition might be caused from the vapor diffusion in the selective growth on three dimensional structure.

選択MOVPE法を用いた極性・非極性GaNストライプ上へのInGaN/GaN MQW構造の作製 Reviewed

TANIKAWA Tomoyuki, HONDA Yoshio, YAMAGUCHI Masahito

IEICE technical report Vol. 109 ( 423 ) page： 23 - 28 2010.2

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

We investigated the InGaN/GaN multiple quantum well (MQW) thickness and luminescence distribution on non c-plane GaN stripes. In the case of non-polar crystal, InGaN MQW at the edge region was thicker than the center region. On the other hand, we got uniform thickness on semi-polar crystals. We simulated the diffusion process in gas phase and estimated the diffusion length of chemical species on each facets. The estimated results suggested that the non-uniformity of thickness was attributed to the chemical source diffusion from vapor phase. While CL spectra showed broad InGaN peak, there were no difference between the center and edge region. We concluded that non-uniformity of thickness and/or composition might be caused from the vapor diffusion in the selective growth on three dimensional structure.

HVPE growth of a-plane GaN on a GaN template (110)Si substrate Reviewed

Tanikawa Tomoyuki, Suzuki Noriyuki, Honda Yoshio, Yamaguchi Masahito, Sawaki Nobuhiko

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 7, NO 7-8 Vol. 7 ( 7-8 ) 2010

Selective growth and impurity incorporation in semipolar GaN grown on Si substrate Reviewed

N. Sawaki, Y. Honda, T. Hikosaka, S. Tanaka, M. Yamaguchi, N. Koide, K. Tomita

GALLIUM NITRIDE MATERIALS AND DEVICES V Vol. 7602 2010

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPIE-INT SOC OPTICAL ENGINEERING

Semipolar nitrogen terminated (1-101) GaN film was grown on a patterned (001) Si substrate using selective area metal organic vapor phase epitaxy. By using a high temperature grown AlN buffer layer upon oblique (111) Si facets on the substrate, we achieved a GaN crystal film with low dislocation density. Because the growth of GaN crystal was self-organized on the facets, we achieved two dimensional growth mode automatically, and the surface roughness was as small as 0.2nm. Incorporation of magnesium (Mg) and carbon (C) in the (1-101) GaN was studied extensively. It was found that the Mg doping efficiency is superior on (1-101) face to that on (0001) face. In case of C doping, a shallow acceptor level was generated in (1-101) face and p-type conduction was realized.

DOI： 10.1117/12.840460

Percolation transport in an AlGaN/GaN heterostructure Invited Reviewed Open Access

N. Sawaki, X. X. Han, Y. Honda, and M. Yamaguchi

Journal of Physics: Conference Series Vol. 193 page： 012012_1-012012_4 2009.11

Influence of a SiO2 Mask on the Growth of Semi-Polar (11-22) GaN on Patterned Si (311) Substrates Reviewed

M. Yang, H. S. Ahn, T. Tanikawa, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Korean Phys. Soc. Vol. 54 ( 6 ) page： 2363 2009.6

Influence of a SiO2 Mask on the Growth of Semi-Polar (11-22) GaN on Patterned Si (311) Substrates Reviewed

M. Yang, H. S. Ahn, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

J. Korean Phys. Soc. Vol. 54 ( 6 ) page： 2363 2009.6

*DAP emission band in a carbon doped (1-101)GaN grown on (001)Si substrate Reviewed

Y. Honda, T. Hikosaka, M. Yamaguchi, N. Sawaki, G. Pozina, F. Karlsson, V. Darakchieva, P. Paskov, and B. Monemar

phys. stat. sol. (c) Vol. 6 ( S2 ) page： S772 2009.5

*DAP emission band in a carbon doped (1-101)GaN grown on (001)Si substrate Reviewed

Y. Honda, T. Hikosaka, M. Yamaguchi, N. Sawaki, G. Pozina, F. Karlsson, V. Darakchieva, P. Paskov, B. Monemar

phys. stat. sol. (c) Vol. 6 ( S2 ) page： S772 2009.5

*Growth and properties of semi-polar GaN on a patterned silicon substrate Reviewed

N. Sawaki, T. Hikosaka, N. Koide, S. Tanaka, Y. Honda, and M. Yamaguchi

J. Cryst. Growth Vol. 311 ( 10 ) page： 2867 2009.3

Maskless selective growth of semi-polar (11-22) GaN on Si (311) substrate by metal organic vapor phase epitaxy Reviewed

M. Yang, H. S. Ahn, T. Tanikawa, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 311 ( 10 ) page： 2914 2009.3

MOVPE growth and properties of GaN on (111)Si using an AlInN intermediate layer Reviewed

M. Irie, N. Koide, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 311 ( 10 ) page： 2891 2009.3

*Reduction of dislocations in a (11-22)GaN grown by selective MOVPE on (113)Si Reviewed

T. Tanikawa, Y. Kagohashi, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 311 ( 10 ) page： 2879 2009.3

*HVPE growth of semi-polar (11-22)GaN on GaN template (113)Si substrate Reviewed

N. Suzuki, T. Uchida, T. Tanikawa, T. Hikosaka, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 311 ( 10 ) page： 2875 2009.3

*Growth and properties of semi-polar GaN on a patterned silicon substrate Reviewed

N. Sawaki, T. Hikosaka, N. Koide, S. Tanaka, Y. Honda, M. Yamaguchi

J. Cryst. Growth Vol. 311 ( 10 ) page： 2867 - 2867 2009.3

*Reduction of dislocations in a (11-22)GaN grown by selective MOVPE on (113)Si Reviewed

T. Tanikawa, Y. Kagohashi, Y. Honda, M. Yamaguchi, N. Sawaki

J. Cryst. Growth Vol. 311 ( 10 ) page： 2879 2009.3

*HVPE growth of semi-polar (11-22)GaN on GaN template (113)Si substrate Reviewed

N. Suzuki, T. Uchida, T. Tanikawa, T. Hikosaka, Y. Honda, M. Yamaguchi, N. Sawaki

J. Cryst. Growth Vol. 311 ( 10 ) page： 2875 2009.3

Maskless selective growth of semi-polar (11-22) GaN on Si (311) substrate by metal organic vapor phase epitaxy Reviewed

M. Yang, H. S. Ahn, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

J. Cryst. Growth Vol. 311 ( 10 ) page： 2914 2009.3

MOVPE growth and properties of GaN on (111)Si using an AlInN intermediate layer Reviewed

M. Irie, N. Koide, Y. Honda, M. Yamaguchi, N. Sawaki

J. Cryst. Growth Vol. 311 ( 10 ) page： 2891 2009.3

Scattering times in the two-dimensional electron gas of AlxGa1-xN/AlN/GaN heterostructures Reviewed

X.X. Han XX, T. Honda, T. Narita, M. Yamaguchi, N. Sawaki, T. Tanaka, Q.X. Guo, and M. Nishio

J. Phys. D Vol. 42 ( 4 ) page： 045112-1 2009.1

Scattering times in the two-dimensional electron gas of AlxGa1-xN/AlN/GaN heterostructures Reviewed

X.X. Han XX, T. Honda, T. Narita, M. Yamaguchi, N. Sawaki, T. Tanaka, Q.X. Guo, M. Nishio

J. Phys. D Vol. 42 ( 4 ) page： 045112-1 2009.1

DAP emission band in a carbon doped (1-101)GaN grown on (001)Si substrate Reviewed

Honda Yoshio, Hikosaka Toshiki, Yamaguchi Masahito, Sawaki Nobuhiko, Pozina Galia, Karlsson Fredrik, Darakchieva Vanya, Paskov Plamen, Monemar Bo

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 6, SUPPL 2 Vol. 6 page： S772 - S775 2009

Percolation transport in an AlGaN/GaN heterostructure Invited Reviewed Open Access

N. Sawaki, X. X. Han, Y. Honda, M. Yamaguchi

16TH INTERNATIONAL CONFERENCE ON ELECTRON DYNAMICS IN SEMICONDUCTORS, OPTOELECTRONICS AND NANOSTRUCTURES (EDISON 16) Vol. 193 page： 012012_1-012012_4 2009

Language：English Publishing type：Research paper (international conference proceedings) Publisher：IOP PUBLISHING LTD

Magneto-transport in an AlGaN/GaN heterostructure has been studied at 4.2K and it was found that the magneto-resistance is negative at low fields. The negative components disappeared by inserting a thin AlN film between the AlGaN barrier layer and the GaN layer. The negative component is attributed to the presence of alloy disorder at the hetero-interface. It increases linearly followed by saturation, which is characteristic to the percolation transport in random potential.

DOI： 10.1088/1742-6596/193/1/012012

Time-resolved spectroscopy in an undoped GaN (1-101) Reviewed Open Access

E.H. Kim, T. Hikosaka, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 5 ( 1 ) page： 367-369 2008

Growth of semi-polar (11-22)GaN on a (113)Si substrate by selective MOVPE Reviewed

T. Tanikawa, T. Hikosaka, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 5 ( 9 ) page： 2966-2968 2008

*Fabrication and properties of semi-polar (1-101) and (11-22) InGaN/GaN light emitting diodes on patterned Si substrates Reviewed

T. Hikosaka, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

phys. stat. sol. (c) Vol. 5 ( 6 ) page： 2234?2237 2008

Energy relaxation processes of photo-generated carriers in Mg doped (0001)GaN and (1-101)GaN Reviewed

J. Saida, E. H. Kim, T. Hikosaka, Y. Honda, M. Yamaguchi, N. Sawaki

phys. stat. sol. (c) Vol. 5 ( 6 ) page： 1746?1749 2008

Time-resolved spectroscopy in an undoped GaN (1-101) Reviewed Open Access

E.H. Kim, T. Hikosaka, Y. Honda, M. Yamaguchi, N. Sawaki

phys. stat. sol. (c) Vol. 5 ( 1 ) page： 367-369 2008

Fabrication and properties of semi-polar (1-101) and (11-22) InGaN/GaN light emitting diodes on patterned Si substrates Reviewed

T. Hikosaka, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 5, NO 6 Vol. 5 ( 6 ) page： 2234 - 2237 2008

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-V C H VERLAG GMBH

InGaN/GaN light emitting diodes (LEDS) were fabricated on semi-polar (1-101) and, (11-22) GaN templates which had been grown on patterned (001) and (113)Si substrates, respectively. The GaN templates were of 300 x 300 mu m(2) discs formed by the coalescence of GaN stripes grown by selective MOVPE method. The n-type electrode was fabricated on the back surface of,the Si substrate. The elecetroluminescence (EL) peaks were observed around 440 nm and 420 nm in (14104) and (11-22) LEDs, respectively. The full width at half,maximum (FWHM) of the peaks at 20 mA were 33 nm ((1-101) LED)and 21 nm ((11-22) LED). The emission peak I was slightly blue-shifted at high drive currents, which was smaller than that of conventional c-plane LEDs, The turn-on voltage of the diodes was of the order of 3-4 V. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/pssc.200778642

Energy relaxation processes of photo-generated carriers in Mg doped (0001)GaN and (1-101)GaN Reviewed

J. Saida, E. H. Kim, T. Hikosaka, Y. Honda, M. Yamaguchi, N. Sawaki

PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 5, NO 6 Vol. 5 ( 6 ) page： 1746 - 1749 2008

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-V C H VERLAG GMBH

Energy relaxation processes of photo-generated excess carriers in Mg doped GaN epitaxial layers were investigated at room temperature, with photoluminescence intensity correlation method using femto-second pulse laser as the excitation source. The decay curve Was well fitted by exponential decay with two time constants. The slow process of the order of 100 ps was attributed to the energy relaxation of electrons in the conduction band, while the fast process of the order of several pico-seconds was attributed to the capture process in the impurity band near the valence band. Little difference has been found out between the results for (0001)GaN and those for (1-101)GaN.

DOI： 10.1002/pssc.200778620

Growth of semi-polar (11-22)GaN on a (113)Si substrate by selective MOVPE Reviewed

T. Tanikawa, T. Hikosaka, Y. Honda, M. Yamaguchi, N. Sawaki

phys. stat. sol. (c) Vol. 5 ( 9 ) page： 2966-2968 2008

Energy relaxation processes of photo-generated carriers in Mg doped (0001)GaN and (1-101)GaN Reviewed

J. Saida, E. H. Kim, T. Hikosaka, Y. Honda, M. Yamaguchi, N. Sawaki

Physica Status Solidi (C) Current Topics in Solid State Physics Vol. 5 ( 6 ) page： 1746 - 1749 2008

Language：English Publishing type：Research paper (international conference proceedings)

Energy relaxation processes of photo-generated excess carriers in Mg doped GaN epitaxial layers were investigated at room temperature, with photoluminescence intensity correlation method using femto-second pulse laser as the excitation source. The decay curve was well fitted by exponential decay with two time constants. The slow process of the order of 100 ps was attributed to the energy relaxation of electrons in the conduction band, while the fast process of the order of several pico-seconds was attributed to the capture process in the impurity band near the valence band. Little difference has been found out between the results for (0001)GaN and those for (1-101)GaN. © 2008 Wiley-VCH Verlag GmbH &amp
Co. KGaA.

DOI： 10.1002/pssc.200778620

Fabrication and properties of semi-polar (1-101) and (11-22) InGaN/GaN light emitting diodes on patterned Si substrates Reviewed

T. Hikosaka, T. Tanikawa, Y. Honda, M. Yamaguchi, N. Sawaki

Physica Status Solidi (C) Current Topics in Solid State Physics Vol. 5 ( 6 ) page： 2234 - 2237 2008

Language：English Publishing type：Research paper (international conference proceedings)

InGaN/GaN light emitting diodes (LEDs) were fabricated on semi-polar (1-101) and (11-22) GaN templates which had been grown on patterned (001) and (113)Si substrates, respectively. The GaN templates were of 300 x 300 μm 2 discs formed by the coalescence of GaN stripes grown by selective MOVPE method. The n-type electrode was fabricated on the back surface of the Si substrate. The electroluminescence (EL) peaks were observed around 440 nm and 420 nm in (1-101) and (11-22) LEDs, respectively. The full width at half maximum (FWHM) of the peaks at 20 mA were 33 nm ((1-101) LED) and 21 nm ((11-22) LED). The emission peak was slightly blue-shifted at high drive currents, which was smaller than that of conventional c-plane LEDs. The turn-on voltage of the diodes was of the order of 3-4 V. © 2008 Wiley-VCH Verlag GmbH &amp
Co. KGaA.

DOI： 10.1002/pssc.200778642

Si基板上でのGaNマイクロファセット上へのInGaN/GaN選択MOVPE成長 Reviewed

Growth of non-polar (1 1 2̄ 0)GaN on a patterned (1 1 0)Si substrate by selective MOVPE Reviewed

Tanikawa, T, Rudolph, D, Hikosaka, T, Honda, Y, Yamaguchi, M, Sawaki, N

J Cryst Growth Vol. 310 ( 23 ) page： 4999 - 5002 2008

中島由樹, 本田善央, 山口雅史, 澤木宣彦

電子情報通信学会技術研究報告. CPM, 電子部品・材料 Vol. 107 ( 252 ) page： 97 - 102 2007.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

選択MOVPE法により(111)Si基板上に作製された(0001)面と(1-101)面からなるGaN台形ストライプ構造上にInGaN/GaNヘテロ構造のMOVPE成長を試みた。InGaN混晶薄膜の膜厚は各々のファセット面上で一様でなく、顕著なリッジ成長が見られた。CLスペクトルから組成均一性を評価したところ、(0001)面上ではスペクトルの中央値(ピーク値)は面上で一様であったが、リッジ部でスペクトル半値幅が増加し組成揺らぎが増強されることが分かった。これらの結果は気相中あるいはファセット表面上での化学種の拡散現象だけでは説明できなかった。

Si基板上でのGaNマイクロファセット上へのInGaN/GaN選択MOVPE成長 Reviewed

中島由樹, 本田善央, 山口雅史, 澤木宣彦

電子情報通信学会技術研究報告. LQE, レーザ・量子エレクトロニクス Vol. 107 ( 253 ) page： 97 - 102 2007.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

Si基板上でのGaNマイクロファセット上へのInGaN/GaN選択MOVPE成長 Reviewed

中島由樹, 本田善央, 山口雅史, 澤木宣彦

電子情報通信学会技術研究報告. ED, 電子デバイス Vol. 107 ( 251 ) page： 97 - 102 2007.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：一般社団法人電子情報通信学会

MOVPE growth and cathodoluminescence properties of GAN microcrystal co-doped with Zn and Si Reviewed

Y. Honda, Y. Yanase, M. Tsuji, M. Yamaguchi, N. Sawaki

JOURNAL OF CRYSTAL GROWTH Vol. 300 ( 1 ) page： 110 - 113 2007.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

A (1 1 1) Si micro-facet was fabricated by KOH anisotropic etching on a (0 0 1) Si substrate. On the (1 1 1) Si facet, a GaN:Zn, Si-microcrystal was grown by selective metal-organic vapor phase epitaxy using an AlN intermediate layer and covered with an AlN capping layer. The size of the AlN/GaN/AlN microcrystal was determined by that of the (1 1 1) Si facet on the substrate. The optical properties of sample were evaluated by cathodoluminescence (CL) measurement. The CL intensity of DAP emission band was enhanced by reducing the crystal size. On the other hand, in the case of samples without AlN capping layer, the CL intensity was decreased with the smaller crystals. This result suggests that the optical confinement does enhance the CL intensity in the AlN/GaN/AlN sample. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jcrysgro.2006.11.001

Transport properties of the two-dimensional electron gas in AlxGa1-xN/GaN heterostructures

Xiuxun Han, Yoshio Honda, Tetsuo Narita, Masahito Yamaguchi, Nobuhiko Sawaki

JOURNAL OF PHYSICS-CONDENSED MATTER Vol. 19 ( 4 ) page： 046204 2007.1

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Magnetotransport measurements were performed on a series of AlxGa1-xN/GaN heterostructures with different Al compositions (x = 0.15, 0.20 and 0.30) at 4.2 K. Adopting a fast Fourier transform method, we analysed the Shubnikov de Hass oscillations due to the two-dimensional electron gas to derive the quantum scattering time (tau(q)). It was found that the quantum scattering time in the ground subband decreases with increasing Al composition: 0.194 ps (x = 0.15), 0.174 ps (x = 0.20) and 0.123 ps (x = 0.30), respectively. To discern the predominant scattering process, the scattering time limited by interface roughness, the residual impurity and the alloy disorder were investigated numerically by including inter-subband scattering. We found that enhanced interface roughness scattering dominates both the transport and quantum scattering time in the ground subband.

DOI： 10.1088/0953-8984/19/4/046204

Fabrication of SAG-AlGaN/InGaN/AlGaN LEDs by mixed-source HVPE with multi-sliding boat system Reviewed

K. H. Kim, K. S. Jang, S. L. Hwang, H. S. Jeon, W. J. Choi, M. Yang, H. S. Ahn, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki, J. Yoo, S. M. Lee, and M. Koike

phys. stat. sol. (c) Vol. 4 ( 1 ) page： 29?32 2007

Acceptor Level due to Carbon in a (1?101)AlGaN Reviewed

N. Sawaki, N. Koide, T. Hikosaka, Y. Honda, and M. Yamaguchi

AIP Conf. Proc. Vol. 893 page： 281-282 2007

Al doping in (1?101) GaN films grown on patterned (001) Si substrate Reviewed

T. Hikosaka, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Appl. Phys. Vol. 101 ( 10 ) page： 103513-1-103513-5 2007

MOVPE growth and cathodoluminescence properties of GAN microcrystal co-doped with Zn and Si Reviewed

Y. Honda, Y. Yanase, M. Tsuji, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 300 ( 1 ) page： 110-113 2007

Mg doping in (1-101)GaN grown on a 7o off-axis (001)Si substrate by selective MOVPE Reviewed

T. Hikosaka, N. Koide, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 298 page： 207-210 2007

Transport properties of the two-dimensional electron gas in AlxGa1?xN/GaN heterostructures Reviewed

X. Han, Y. Honda, T. Narita, M. Yamaguchi and N. Sawaki

J. Phys.: Condens. Matter Vol. 19 ( 4 ) page： 046204_1-046204_11 2007

Characterization of AlGaN, Te-doped GaN and Mg-doped GaN grown by hydride vapor phase epitaxy Reviewed

K. S. Jang, K. H. Kim, S. L. Hwang, H. S. Jeon, H. S. Ahn, M. Yang, W. J. Choi, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki, J. Yoo, S. M. Lee, and M. Koike

phys. stat. sol. (c) Vol. 4 ( 1 ) page： 133?136 2007

Growth of InGaN layer on GaN templated Al2O3 (0001) and Si (111) substrates by mixed-source HVPE Reviewed

S. L. Hwang, K. S. Jang, K. H. Kim, H. S. Jeon, H. S. Ahn, M. Yang, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki, J. Yoo, S. M. Lee, and M. Koike

phys. stat. sol. (c) Vol. 4 ( 1 ) page： 125?128 2007

Time-resolved photoluminescence spectroscopy in a GaN/AlGaN SQW structure grown on a (111) Si substrate Reviewed

E.H. Kim, T. Narita, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 4 ( 7 ) page： 2838-2841 2007

Electron-Beam-Induced-Current Investigation of GaN/AlGaN/Si Heterostructures Using Scanning Transmission Electron Microscopy Reviewed

S. Tanaka, K. Aoyama, M. Ichihashi, S. Arai, Y. Honda, and N. Sawaki

J. Electron Microsc. Vol. 56 ( 4 ) page： 141-144 2007

Application of electron holography to the determination of contact potential difference in an AIGaN/AIN/Si heterostructure Reviewed

S. Tanaka, A. Naito, Y. Honda, N. Sawaki, and M. Ichihashi

J. Electron Microsc. Vol. 56 ( 2 ) page： 37-42 2007

Characterization of AlGaN/InGaN/AlGaN heterostructure with selective area growth of Te-doped AlGaN cladding layer grown by mixed-source HVPE Reviewed

K. S. Jang, K. H. Kim, S. L. Hwang, H. S. Jeon, M. Yang, H. S. Ahn, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki, S. H. Jang, S. M. Lee, and M. Koike

phys. stat. sol. (c) Vol. 4 ( 7 ) page： 2240-2243 2007

Subband structure and transport properties of two-dimensional electron gas in AlxGa1-xN/GaN heterostructures Reviewed

X. Han, Y. Honda, T. Narita, M. Yamaguchi and N. Sawaki

phys. stat. sol. (c) Vol. 4 ( 7 ) page： 2334-2337 2007

The surface diffusion of Ga species on an AlGaN facet structure in low pressure MOVPE Reviewed

T. Narita, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 4 ( 7 ) page： 2506-2509 2007

Series resistance in a GaN/AlGaN/n-Si structure grown by MOVPE Reviewed

Y. Honda, S. Kato, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 4 ( 7 ) page： 2740-2743 2007

Series resistance in a GaN/AlGaN/n-Si structure grown by MOVPE Reviewed

Y. Honda, S. Kato, M. Yamaguchi, N. Sawaki

phys. stat. sol. (c) Vol. 4 ( 7 ) page： 2740-2743 2007

Subband structure and transport properties of two-dimensional electron gas in AlxGa1-xN/GaN heterostructures Reviewed

X. Han, Y. Honda, T. Narita, M. Yamaguchi, N. Sawaki

phys. stat. sol. (c) Vol. 4 ( 7 ) page： 2334-2337 2007

The surface diffusion of Ga species on an AlGaN facet structure in low pressure MOVPE Reviewed

T. Narita, Y. Honda, M. Yamaguchi, N. Sawaki

phys. stat. sol. (c) Vol. 4 ( 7 ) page： 2506-2509 2007

Time-resolved photoluminescence spectroscopy in a GaN/AlGaN SQW structure grown on a (111) Si substrate Reviewed

E.H. Kim, T. Narita, Y. Honda, M. Yamaguchi, N. Sawaki

phys. stat. sol. (c) Vol. 4 ( 7 ) page： 2838-2841 2007

Acceptor level due to carbon in a (1-101)AlGaN Reviewed

N. Sawaki, N. Koide, T. Hikosaka, Y. Honda, M. Yamaguchi

PHYSICS OF SEMICONDUCTORS, PTS A AND B Vol. 893 page： 281 - + 2007

Language：English Publishing type：Research paper (international conference proceedings) Publisher：AMER INST PHYSICS

Carbon doping into N terminated GaN and AlGaN epitaxial layer is investigated. We found strong carbon related emission band which is insensitive to the annealing effect. The results suggested a shallow acceptor level which was slightly increased by the increase of the Al composition. A possible mechanism of the shallow level is discussed.

Growth of InGaN layer on GaN templated Al2O3 (0001) and Si (111) substrates by mixed-source HVPE Reviewed

S. L. Hwang, K. S. Jang, K. H. Kim, H. S. Jeon, H. S. Ahn, M. Yang, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki, J. Yoo, S. M. Lee, M. Koike

PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 4, NO 1 Vol. 4 ( 1 ) page： 125 - + 2007

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-V C H VERLAG GMBH

The InGaN layers on GaN templated sapphire (000 1) and Si (I 11) substrates are grown by mixed-source hydride vapor phase epitaxy (HVPE) method. As a new attempt in obtaining an InGaN layers, the growth of the thick InGaN layer is performed by putting small amount of Ga into the In source. The InGaN layer is compounded from chemical reaction between a NH3 and an Indium-gallium chloride formed by HCI flown over metallic In mixed with Ga. The InGaN layer is analyzed by X-ray photoelectron spectroscopy (XPS) to characterize the InGaN ternary crystal alloy. The optical property of the selective area growth (SAG) of the InGaN layer is investigated by the photoluminescence (PL) spectrum and the cathodoluminescence (CL) images. Indium compositions are estimated to be in the range 3-10 %. In order to obtain the GaN layer on GaN ternplated Si (111) substrates, an InGaN layer is used as an intermediate layer. The PL and CL of the InGaN intermediate layer are measured at 300K. We find that the InGaN intermediate layer is possible to be one of the growth methods of thick GaN layer on Si substrates by HVPE method.

DOI： 10.1002/pssc.200673507

Fabrication of SAG-AlGaN/InGaN/AlGaN LEDs by mixed-source HVPE with multi-sliding boat system Reviewed

K. H. Kim, K. S. Jang, S. L. Hwang, H. S. Jeon, W. J. Choi, M. Yang, H. S. Ahn, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki, J. Yoo, S. M. Lee, M. Koike

PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 4, NO 1 Vol. 4 ( 1 ) page： 29 - + 2007

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-V C H VERLAG GMBH

The selective area growth (SAG) of AlGaN/InGaN/AlGaN light-emitting diodes (LEDs) is performed by mixed-source hydride vapor phase epitaxy (HVPE). In order to obtain the SAG-AlGaN/InGaN/AlGaN heterostructure, a special graphite fixture to use in HVPE is designed. First, an n-type AlGaN layer is grown at 1090 degrees C on a GaN templated (0001) sapphire substrate with a patterned SAG-structure of a silicon oxide (SiO2). On this selectively grown n-type AlGaNT layer, a nominally undoped-InGaN layer is grown using an In-Ga mixed metallic source at 990 degrees C. After the growth of InGaN layer, Mg-doped AlGaN and Mg-doped GaN layers are grown as a cladding and capping layers at 1090 degrees C and 1050 degrees C, respectively. All of the epitaxial layers of LED structure are grown consecutively with a multi-sliding boat system. Room-temperature electroluminescence (EL) characteristics show an emission peak wavelength of 415 nm with a full width at half-maximum (FWHM) of approximately 0.37 eV. We find that the mixed-source HVPE method with multi-sliding boat system is possible to be one of the growth methods of Ill-nitride LEDs. (c) 2007 WILEYNCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/pssc.200673508

Electron-Beam-Induced-Current Investigation of GaN/AlGaN/Si Heterostructures Using Scanning Transmission Electron Microscopy Reviewed

S. Tanaka, K. Aoyama, M. Ichihashi, S. Arai, Y. Honda, N. Sawaki

J. Electron Microsc. Vol. 56 ( 4 ) page： 141-144 2007

Characterization of AlGaN/InGaN/AlGaN heterostructure with selective area growth of Te-doped AlGaN cladding layer grown by mixed-source HVPE Reviewed

K. S. Jang, K. H. Kim, S. L. Hwang, H. S. Jeon, M. Yang, H. S. Ahn, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki, S. H. Jang, S. M. Lee, M. Koike

PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 4 NO 7 2007 Vol. 4 ( 7 ) page： 2240 - + 2007

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-V C H VERLAG GMBH

The selective area growth (SAG) of AlGaN/InGaN/AlGaN light-emitting diodes (LEDs) is performed by mixed-source hydride vapor phase epitaxy (HVPE). The structure is grown on a n-GaN templated (0001) sapphire substrate. The SAG-double heterostructure (DH) is consisted of a Te-doped AlGaN cladding layer, an InGaN active layer, a Mg-doped AlGaN cladding layer, and a Mg-doped GaN capping layer. All of the epitaxial layers of LED structure are grown consecutively with a multi-sliding boat system. Room-temperature electroluminescence (EL) characteristics show an emission peak wavelength of 400 nm with a full width at half-maximum (FWHM) of approximately 0.38 eV (at 20 mA). We find that the mixed-source HVPE method with multi-sliding boat system is possible to be one of the growth methods of III-nitride LEDs. (c) 2007 WILEYNCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/pssc.200674799

Characterization of AlGaN, Te-doped GaN and mg-doped GaN grown by hydride vapor phase epitaxy Reviewed

K. S. Jang, K. H. Kim, S. L. Hwang, H. S. Jeon, H. S. Ahn, M. Yang, W. J. Choi, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki, J. Yoo, S. M. Lee, M. Koike

PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 4, NO 1 Vol. 4 ( 1 ) page： 133 - + 2007

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-V C H VERLAG GMBH

The AlxGa1-xN, Te-doped GaN and Mg-doped GaN layers on GaN/A1(2)O(3) substrates are grown by mixed-source hydride vapor phase epitaxy (HVPE) method. The metallic Ga mixed with Al is used as group Ill source material to get the AlxGa1-xN layers. The values of the compositions x of the AI(x)Ga(1-x)N layers characterized by X-ray diffraction (XRD) measurements are 0.6 % similar to 80 % at the various temperatures of the source zone. The metallic Ga mixed with Te (or Mg) is used as source material for n-type (or p-type) doping. The electron concentrations of the Te-doped GaN layers are varied from 1.8 X 10(17) to 8.3 x 10(18)/cm(3). The hole concentrations of the Mg-doped GaN layers are varied from 1.5 x 10(16) to 3.2 x 10(16)/cm(3). We find that the mixed-source HVPE method is suitable to get a thick AlGaN layer with an arbitrary composition, a Te-doped GaN layer with a high n-type concentration and a Mg-doped GaN layer with p-type concentration.

DOI： 10.1002/pssc.200673506

Application of electron holography to the determination of contact potential difference in an AIGaN/AIN/Si heterostructure Reviewed

S. Tanaka, A. Naito, Y. Honda, N. Sawaki, M. Ichihashi

J. Electron Microsc. Vol. 56 ( 2 ) page： 37-42 2007

Al doping in (1?101) GaN films grown on patterned (001) Si substrate Reviewed

T. Hikosaka, Y. Honda, M. Yamaguchi, N. Sawaki

J. Appl. Phys. Vol. 101 ( 10 ) page： 103513-1-103513-5 2007

Mg doping in (1-101)GaN grown on a 7o off-axis (001)Si substrate by selective MOVPE Reviewed

T. Hikosaka, N. Koide, Y. Honda, M. Yamaguchi, N. Sawaki

J. Cryst. Growth Vol. 298 page： 207-210 2007

Growth and doping of AlGaN and electroluminescence of SAG-InGaN/AlGaN heterostructure by mixed-source HVPE Reviewed

K. H. Kim, H. S. Ahn, M. Yang, K. S. Jang, S. L. Hwang, W. J. Choi, C. R. Cho, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki, J. Yoo, S. M. Lee, and M. Koike

phys. stat. sol. (c) Vol. 3 ( 6 ) page： 1461?1465 2006

Carbon Incorporation on (1-101) Facet of AlGaN in Metal Organic Vapor Phase Epitaxy Reviewed

N. Koide, T. Hikosaka, Y. Honda, M. Yamaguchi, and N. Sawaki

Jpn. J. Appl. Phys. Vol. 45 ( 10A ) page： 7655-7660 2006

Series Resistance in n-GaN/AlN/n-Si Heterojunction Structure Reviewed

H. Kondo, N. Koide, Y. Honda, M. Yamaguchi, and N. Sawaki

Jpn. J. Appl. Phys. Vol. 45 ( 5A ) page： 4015?4017 2006

Optical spectra of (1-101) InGaN/GaN and GaN/AlGaN MQW structure grown on a 7 degree off axis (001) Si substrate Reviewed

E. H. Kim, T. Hikosaka, T. Narita, Y. Honda, N. Sawaki

phys. stat. sol. (c) Vol. 3 ( 6 ) page： 1992?1996 2006

p-type conduction in a C-doped (1-101)GaN grown on a 7-degree-off oriented (001)Si substrate by selective MOVPE Reviewed

T. Hikosaka, N. Koide, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 3 ( 6 ) page： 1425?1428 2006

Cathodoluminescence properties of InGaN codoped with Zn and Si Reviewed Open Access

Y. Honda, Y. Yanase, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 3 ( 6 ) page： 1915?1918 2006

The surface diffusion of Ga on an AlGaN/GaN stripe structure in the selective MOVPE Reviewed

T. Narita, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (b) Vol. 243 ( 7 ) page： 1665?1668 2006

The surface diffusion of Ga on an AlGaN/GaN stripe structure in the selective MOVPE Reviewed

T. Narita, Y. Honda, M. Yamaguchi, N. Sawaki

phys. stat. sol. (b) Vol. 243 ( 7 ) page： 1665?1668 - 1668 2006

Optical spectra of (1-101) InGaN/GaN and GaN/AlGaN MQW structure grown on a 7 degree off axis (001) Si substrate Reviewed

E. H. Kim, T. Hikosaka, T. Narita, Y. Honda, N. Sawaki

phys. stat. sol. (c) Vol. 3 ( 6 ) page： 1992?1996 2006

p-type conduction in a C-doped (1-101)GaN grown on a 7-degree-off oriented (001)Si substrate by selective MOVPE Reviewed

T. Hikosaka, N. Koide, Y. Honda, M. Yamaguchi, N. Sawaki

PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 3, NO 6 Vol. 3 ( 6 ) page： 1425 - 1428 2006

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-VCH, INC

Using a selective metal organic vapour phase epitaxy method, (1-101)GaN was grown on a (001)Si substrate. Intentional carbon doping was attempted using CCl4 as the souce gas and the electrical properties were studied as a function of the doping level. All samples showed the p-type conduction. The hole concentration was increased by the doping, determined by the ratio of the carbon source and NH3 flow rates. The results indecated that the p-type conduction is due to the incorporation of carbon in the (1-101)GaN. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/pssc.200565305

Series Resistance in n-GaN/AlN/n-Si Heterojunction Structure Reviewed

H. Kondo, N. Koide, Y. Honda, M. Yamaguchi, N. Sawaki

Jpn. J. Appl. Phys. Vol. 45 ( 5A ) page： 4015?4017 2006

Carbon Incorporation on (1-101) Facet of AlGaN in Metal Organic Vapor Phase Epitaxy Reviewed

N. Koide, T. Hikosaka, Y. Honda, M. Yamaguchi, N. Sawaki

Jpn. J. Appl. Phys. Vol. 45 ( 10A ) page： 7655-7660 2006

Growth and doping of AlGaN and electroluminescence of SAG-InGaN/AlGaN heterostructure by mixed-source HVPE Reviewed

K. H. Kim, H. S. Ahn, M. Yang, K. S. Jang, S. L. Hwang, W. J. Choi, C. R. Cho, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki, J. Yoo, S. M. Lee, M. Koike

PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 3, NO 6 Vol. 3 ( 6 ) page： 1461 - 1465 2006

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-VCH, INC

The AlxGa1-xN layers on GaN/Al2O3 substrates are grown by mixed-source hydride vapor phase epitaxy (HVPE) at various temperatures of the source zone. We find source zone temperature dependence of the composition x of AlxGa1-xN layers. Te doping as a new attempt and Si doping in obtaining an n-type Al-GaN layers are performed by putting small amount of Te (or Si) into the Ga-Al source, respectively. In case of Te-doped AlGaN (x = 0.16), the carrier concentration is varied from 1.1 x 10(18) to 8.0 x 10(18)/cm(3), while in case of Si-doped one, it is varied from 2.0 x 10(16) to 1.1 x 10(17)/cm(3). We find the new results that Te doping is more suitable to get a high n-type concentration by mixed-source HVPE. InGaN/GaN multiple quantum wells (MQWs) are grown on the selective area growth (SAG)-Te-doped AlGaN and SAG-Si-doped AlGaN cladding layer by mealorganic chemical vapour deposition (MOCVD), respectively. Furthermore, we investigate the electroluminescence (EL) properties of SAG-LEDs of two different cladding layers. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/pssc.200565306

Cathodoluminescence properties of InGaN codoped with Zn and Si Reviewed Open Access

Y. Honda, Y. Yanase, M. Yamaguchi, N. Sawaki

Physica Status Solidi (C) Current Topics in Solid State Physics Vol. 3 ( 6 ) page： 1915 - 1918 2006

Language：English Publishing type：Research paper (international conference proceedings)

An InGaN alloy co-doped with Zn and Si was grown by metal organic vapor phase epitaxy on a GaN templated silicon substrate and the luminesence (CL) properties are studied by cathodoluminescence spectroscopy. As the result of co-doping of Zn and Si, the CL intensity was extremely enhanced
enhancement in the peak intensity as well as the full-width at half maximum. The optimum doping density was estimated to be N(Zn) = 4.0 × 1019/cm3 and N(Si) = 8.0 × 1018/cm3. © 2006 WILEY-VCH Verlag GmbH &amp
Co. KGaA.

DOI： 10.1002/pssc.200565326

Incorporation of carbon on a (1(1)over-bar01) facet of GaN by MOVPE Reviewed

N Koide, T Hikosaka, Y Honda, M Yamaguchi, N Sawaki

JOURNAL OF CRYSTAL GROWTH Vol. 284 ( 3-4 ) page： 341 - 346 2005.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The incorporation of carbon Using CCl4 or C2H2 in metal-organic vapor phase epitaxy is Studied oil (1 1 0 1) facets of a GaN stripe formed by selective area growth. The optical spectra of the sample were examined by cathode luminescence spectroscopy (CL). An edge emission peak specific to the (1 1 0 1) facet was tentatively assigned to the acceptor bound exciton (ABE). The peak intensity was enhanced by the increase of the carbon doping and determined by the ratio of the carbon source and the NH3 flow rate. The CL image showed that the doping had been achieved uniformly oil the (1 1 0 1) facets but affected by the stress/strain due to the large lattice mismatch against the Si substrate. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jcrysgro.2005.07.021

The effect of Si and C doping to the (1-101)GaN grown on a 7-degree-off oriented (001)Si substrate

HIKOSAKA Toshiki, KOIDE Norikatsu, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

IEICE technical report. Electron devices Vol. 105 ( 90 ) page： 69 - 74 2005.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

The effect of Si and C doping to the (1-101)GaN grown on a 7-degree-off oriented (001)Si substrate

HIKOSAKA Toshiki, KOIDE Norikatsu, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

IEICE technical report. Component parts and materials Vol. 105 ( 92 ) page： 69 - 74 2005.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Characterization of AlGaN layer with high Al content grown by mixed-source HVPE Reviewed

HS Ahn, KH Kim, M Yang, JY Yi, HJ Lee, JH Chang, HS Kim, SW Kim, SC Lee, Y Honda, M Yamaguchi, N Sawaki

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE Vol. 202 ( 6 ) page： 1048 - 1052 2005.5

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

Using mixed-source hydride vapor-phase epitaxy (HVPE). an AlGaN layer with high Al content on GaN/Al2O3 substrate is obtained. The AlGaN layer grown by mixed-source HVPE is characterized by X-ray diffraction (XRD) measurements and cathodoluminescence (CL) spectra. In the mixed-source HVPE technique, the AlGaN material is compounded from the chemical reaction between NH3 and an aluminum-gallium chloride formed using HCl that is flowed over metallic Ga mixed with Al. The XRD measurements indicate that single-crystal hexagonal AlGaN with high Al content had been grown. The CL spectra at 4 K show that the distribution of the Al on the AlGaN surface for very high Al content (x = 0.8 in AlxGa1-xN) is not uniform. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/pssa.200420001

Growth of thick AlGaN by mixed-source hydride vapor phase epitaxy Reviewed

HS Ahn, KH Kim, M Yang, JY Yi, HJ Lee, CR Cho, HK Cho, SW Kim, T Narita, Y Honda, M Yamaguchi, N Sawaki

APPLIED SURFACE SCIENCE Vol. 243 ( 1-4 ) page： 178 - 182 2005.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Growth of a thick AlGaN layer on GaN/Al2O3 substrate is performed by mixed-source hydride vapor phase epitaxy (HVPE) method. The AlGaN material is compounded from chemical reaction between a NH3 and an aluminum-gallium chloride formed by HCl which is flown over metallic Ga mixed with Al. The AlGaN epitaxial layer is analyzed by Auger-electron spectroscopy (AES) and X-ray diffraction (XRD) measurement to characterize the AlGaN. Al concentration is estimated to be in the range of 0.5-6%. We suggest that the metallic Ga mixed with Al can be used as a group III source material in the HVPE growth of the AlGaN layer. (c) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apsusc.2004.09.117

Uniform growth of GaN on AlN templated (111)Si substrate by HVPE Reviewed

Y. Honda, M. Okano, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 2 ( 7 ) page： 2125? 2128 2005

Incorporation of carbon on a (1-101) facet of GaN by MOVPE Reviewed

N. Koide, T. Hikosaka, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 284 ( 3-4 ) page： 341?346 2005

Characterization of AlGaN layer with high Al content grown by mixed-source HVPE Reviewed

H. S. Ahn, K. H. Kim, M. Yang, J. Y. Yi, H. J. Lee, J. H. Chang, H. S. Kim, S. W. Kim, S. C. Lee, Y Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (a) Vol. 202 ( 6 ) page： 1048?1052 2005

Doping in GaN and AlGaN Grown by Mixed-Source Hydride Vapor Phase Epitaxy Reviewed

J. Y. Yi, Kyoung H. Kim, H. J. Lee, M.?Yang, H. S. Ahn, C. R. Cho, S. C. Lee, S. W. Kim, Y. Honda, M. Yamaguchi, and N. Sawaki

Inst. Phys. Conf. Ser. Vol. 184 page： 373-376 2005

Growth of AlGaN on Al2O3 substrates by Mixed-Source HVPE Reviewed

K. H. Kim, J. Y. Yi, H. J. Lee, M. Yang, H. S. Ahn, S. N. Yi, C. R. Cho, S. C. Lee, S. W. Kim, Y. Honda, M. Yamaguchi, and N. Sawaki

Inst. Phys. Conf. Ser. Vol. 184 page： 361-364 2005

Effect of Si doping to the (1-101)GaN grown on a 7 degree off oriented (001)Si by selective MOVPE Reviewed

T. Hikosaka, Y. Honda, N. Koide, M. Yamaguchi, and N. Sawaki

Inst. Phys. Conf. Ser. Vol. 184 page： 251-254 2005

Growth of thick AlGaN by mixed-source hydride vapor phase epitaxy Reviewed

H.S. Ahn, K.H. Kim, M. Yang, J.Y. Yi, H.J. Lee, C.R. Cho, H.K. Cho, S.W. Kim, T. Narita, Y. Honda, M. Yamaguchi, and N. Sawaki

Appl. Surf. Science Vol. 243 ( 1-4 ) page： 178-182 2005

Growth and optical properties of InGaN/GaN quantum well on a (1-101) facet Reviewed

T. Narita, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 2 ( 7 ) page： 2349?2352 2005

Doping in GaN and AlGaN Grown by Mixed-Source Hydride Vapor Phase Epitaxy Reviewed

J. Y. Yi, Kyoung H. Kim, H. J. Lee, M.?Yang, H. S. Ahn, C. R. Cho, S. C. Lee, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki

Inst. Phys. Conf. Ser. Vol. 184 page： 373-376 2005

Growth of AlGaN on Al2O3 substrates by mixed-source HVPE Reviewed

KH Kim, JY Yi, HJ Lee, M Yang, HS Ahn, CR Cho, SW Kim, Y Honda, M Yamaguchi, N Sawaki

COMPOUND SEMICONDUCTORS 2004, PROCEEDINGS Vol. 184 page： 361 - 364 2005

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

The mixed-source hydride vapor phase epitaxy (HVPE) growth of AlGaN layer is performed on Al2O3 substrate. The AlGaN layer is studied by X-ray diffraction (XRD) measurement, Auger electron spectroscopy (AES) analysis and cathodoluminesecence (CL) spectrum to characterize the structural and optical properties. The Al composition estimated by the XRD measurement is 30 %. The room temperature CL spectrum exhibits a weak peak at 323 nm.

Effect of Si doping to the (1-101)GaN grown on a 7 degree off oriented (001)Si by selective MOVPE Reviewed

T Hikosaka, Y Honda, N Koide, M Yamaguchi, N Sawaki

COMPOUND SEMICONDUCTORS 2004, PROCEEDINGS Vol. 184 page： 251 - 254 2005

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

The electrical properties of a (1-101)GaN grown on an Si substrate were studied as a function of Si doping density. It was found that un-intentionally doped samples exhibited p-type conduction, while the doping of Si changed the type of conduction from p-type to n-type. The cathodeluminescence spectra at 4 K exhibited a strong edge emission peak at 357 nm followed by a defect-related emission at 370 nm. The intensity of the latter was enhanced by the Si doping and we found slight blue shift of the emission energy.

Growth and optical properties of InGaN/GaN quantum well on a (1-101) facet Reviewed

T. Narita, Y. Honda, M. Yamaguchi, N. Sawaki

Physica Status Solidi C: Conferences Vol. 2 ( 7 ) page： 2349 - 2352 2005

Language：English Publishing type：Research paper (international conference proceedings)

The growth of an InGaN / GaN double heterostructure (DH) was attempted on a stripe patterned GaN grown on a (111) Si substrate by selective area metal organic vapor phase epitaxy. The cathode luminescence (CL) spectroscopy at 4K suggests that we have an InGaN wire on the (0001) apex. Analysing the CL spectra, we found that the In composition is not uniform on the (1-101) facet, which was attributed to the diffusion of Ga on the facets. But the phenomenon depended on the TMIn (In source gas) flow rate and a uniform In composition was achieved under a certain flow rate. © 2005 WILEY-VCH Verlag GmbH &amp
Co. KGaA, Weinheim.

DOI： 10.1002/pssc.200461558

Uniform growth of GaN on AlN templated (111)Si substrate by HVPE Reviewed

Y. Honda, M. Okano, M. Yamaguchi, N. Sawaki

Physica Status Solidi C: Conferences Vol. 2 ( 7 ) page： 2125 - 2128 2005

Language：English Publishing type：Research paper (international conference proceedings)

Uniform growth of thick GaN was attempted on an AlN templated (111) silicon substrate by hydride vapor phase epitaxy(HVPE). The results were very sensitive to the thickness of the AlN layer as well as the growth temperature. If the AlN is thinner than 50 nm, the surface of the silicon substrate was partly melted during the HVPE growth. If the AlN was thicker than 50 nm, the melting of the silicon surface was drastically suppressed. Uniform growth without degradation of the Si substrate was achieved at 1000°C with a thick AlN template layer. © 2005 WILEY-VCH Verlag GmbH &amp
Co. KGaA, Weinheim.

DOI： 10.1002/pssc.200461575

Doping of GaN, AlGaN by mixed-source HVPE Reviewed

JY Yi, KH Kim, HJ Lee, M Yang, HS Ahn, CR Cho, SW Kim, Y Honda, M Yamaguchi, N Sawaki

COMPOUND SEMICONDUCTORS 2004, PROCEEDINGS Vol. 184 page： 373 - 376 2005

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Mg doped GaN and AlGaN layers were grown by hydrid vapor phase epitaxy (HVPE). Metallic Ga mixed with Mg and (Mg, Al) were used as group III source materials for the growth of GaN:Mg and AlGaN:Mg, respectively. For the crystalline and elemental analysis, double X-ray diffraction (DXRD) and Auger electron spectroscopy (AES) measurements were performed. A luminescence peak at around 380 nm which might be from Mg related recombination center Could be observed in cathodoluminescence (CL) spectroscopy. We could also observed, by Hall effect measurement, effect of counter doping by Mg acceptor in GaN:Mg and AlGaN:Mg layers.

Metalorganic-hydride vapor phase epitaxy growth of GaN/AlN on Si substrates

H. J. Lee, K. H. Kim, J. Y. Yi, M. Yang, H. S. Ahn, J. H. Chang, H. S. Kim, S. N. Yi, S. C. Lee, S. W. Kim, Y. Honda, M. Yamaguchi, N. Sawaki

Journal of the Korean Physical Society Vol. 45 page： S813 - S815 2004.12

Language：English Publishing type：Research paper (international conference proceedings)

High-quality GaN film with AlN buffer layer was successfully grown by using our newly designed metalorganic-hydride vapor-phase epitaxy (MO-HVPE) system. We performed the growth of AlN buffer layer on Si (111) substrates by the use of TMA and NH 3 at 935°C. GaN films were grown on AlN/Si (111) substrates by using metallic Ga, NH 3 and HCl as source materials at 1050&amp
C. The morphologies of the GaN and AlN buffer layers were characterized by scanning electron microscopy (SEM). For the optical characterization of the GaN/AlN/Si, photoluminescence (PL) and cathodoluminescence (CL) spectroscopy were carried out at room temperature.

Optical and electrical properties of (1-101)GaN grown on a 7 degrees off-axis (001)Si substrate Reviewed Open Access

T Hikosaka, T Narita, Y Honda, M Yamaguchi, N Sawaki

APPLIED PHYSICS LETTERS Vol. 84 ( 23 ) page： 4717 - 4719 2004.6

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

Uniform growth of (1-101)GaN was performed on coalesced stripes of GaN which had been prepared by selective metalorganic vapor phase epitaxy on a 7degrees off-axis (001)Si substrate via an AlN intermediate layer. The cathodoluminescence spectra at 4 K exhibited a donor bound excitonic emission at 358 nm followed by defect-related emission peaks at 363, 371, and 376 nm. The 363 and 376 emission bands are observed upon the coalescence region. The Hall measurements exhibited p-type conduction at 80-300 K (the hole carrier density 6.3x10(12) cm(-2) and hole mobility 278 cm(2)/V s at 100 K). The activation energy of the acceptor was estimated to be 60 meV. The possible origin of the p-type conduction is discussed in relation to the unintentionally doped carbon. (C) 2004 American Institute of Physics.

DOI： 10.1063/1.1758300

Growth of GaN/AlN pyramid structure on Si substrate by MOVPE

HONDA Yoshio, NAKAMURA Tsuyoshi, YAMAGUCHI Masahito, SAWAKII Nobuhiko

Technical report of IEICE. SDM Vol. 104 ( 43 ) page： 17 - 22 2004.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

We had grown the GaN/AIN pyramid structure on (111)Si substrate by MOVPE. The non-uniformity of GaN shape was issue to solve. The reason of that was non-uniformity nucleation of AlN intermediate layer. We estimated the uniformity of GaN/AlN pyramid structure with changing the growth time of AlN intermediate layer. In the case of the thin AlN, we got uniform GaN/AlN structure. A thinner film of AlN contribute to the improvement of current-voltage characterization, we think it effective for the field emitting device.

Growth of GaN/AlN pyramid structure on Si substrate by MOVPE

HONDA Yoshio, NAKAMURA Tsuyoshi, YAMAGUCHI Masahito, SAWAKII Nobuhiko

IEICE technical report. Component parts and materials Vol. 104 ( 41 ) page： 17 - 22 2004.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Growth of GaN/AlN pyramid structure on Si substrate by MOVPE

HONDA Yoshio, NAKAMURA Tsuyoshi, YAMAGUCHI Masahito, SAWAKII Nobuhiko

IEICE technical report. Electron devices Vol. 104 ( 39 ) page： 17 - 22 2004.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Photocurrent spectroscopy of a (0001)GaN/AlGaN/(111)Si heterostructure Reviewed

Y Kuroiwa, Y Honda, N Sawaki

PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES Vol. 21 ( 2-4 ) page： 787 - 792 2004.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

A crack-free GaN/AlGaN sample was grown on (111) Si by selective area metal-organic vapor-phase epitaxy method using an AlGaN intermediate layer. The electrical properties of the GaN/AlGaN/Si heterojunction diode were investigated with photocurrent spectroscopy at 77 K. It was found that the current-voltage characteristics depend on the thickness/composition of the intermediate layer. The photocurrent spectra indicated that the energy band of the n-type-doped Si substrate is lifted at the heterointerface, while it is flat in case of the sample grown on a p-type-doped Si. The depletion of the energy band in the n-Si at the heterointerface is attributed to the diffusion of Al during the growth. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physe.2003.11.125

Transmission electron microscopy study of an AlN nucleation layer for the growth of GaN on a 7-degree off-oriented (001)Si substrate by metalorganic vapor phase epitaxy Reviewed

S Tanaka, Y Honda, N Kameshiro, R Iwasaki, N Sawaki, T Tanji, M Ichihashi

JOURNAL OF CRYSTAL GROWTH Vol. 260 ( 3-4 ) page： 360 - 365 2004.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We have investigated the morphology of the high-temperature-grown AlN nucleation layer and its role in the early stage of GaN growth, by means of transmission electron microscopy. The nitride was selectively grown on a 7-degree off-oriented (001) patterned Si substrate by metalorganic vapor phase epitaxy. AlN was deposited on the inclined unmasked (111) facet in the form of islands. The size of the islands varied along the slope, which is attributable to the diffusion of the growth species in the vapor phase. The GaN nucleation occurred at the region where rounded AlN islands formed densely. The threading dislocations were observed to generate in the GaN nucleated region. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jscrysgro.2003.08.074

Photocurrent spectroscopy of a (0001) GaN/AlGaN/(111)Si heterostructure Reviewed

Y. Kuroiwa, Y. Honda, N. Sawaki

Physica E Vol. 21 ( 2-4 ) page： 782-792 2004

Fabrication and optical properties of GaN micro-prism array on an Si substrate Reviewed

A. Nishioka, Y. Honda, and N. Sawaki

Proc. of Int. Conf. on Electrical Engineering 2004 Vol. 3-1 page： 297-300 2004

Optical spectra of GaN/InGaN/GaN MQW structure grown on a (1?101) GaN facet Reviewed

Eun-Hee Kim, Tetsuo Narita, Yoshio Honda, and Nobuhiko Sawaki

phys. stat. sol. (c) Vol. 1 ( 10 ) page： 2512?2515 2004

Transmission electron microscopy study of an AlN nucleation layer for the growth of GaN on a 7-degree off-oriented (001)Si substrate by metalorganic vapor phase epitaxy Reviewed

S. Tanaka, Y. Honda, N. Kameshiro, R. Iwasaki, N. Sawaki, T. Tanji, and M. Ichihashi

J. Cryst. Growth Vol. 260 ( 3-4 ) page： 360-365 2004

Growth of thick AlGaN by metalorganic-hydride vapor phase epitaxy Reviewed

K. H. Kim, J. Y. Yi, H. J. Lee, M. Yang, H. S. Ahn, C. R. Cho, S. W. Kim, S. C. Lee, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 1 ( 10 ) page： 2474?2477 2004

Optical and electrical properties of (1-101)GaN grown on a 7[degree] off-axis (001)Si substrate Reviewed

T. Hikosaka, T. Narita, Y. Honda, M. Yamaguchi, and N. Sawaki

Appl. Phys. Lett. Vol. 84 ( 23 ) page： 4717-4719 2004

Transport properties of the two-dimensional electron gas in AlxGa1-xN/GaN heterostructures Reviewed

B Shen

2004: 7TH INTERNATIONAL CONFERENCE ON SOLID-STATE AND INTEGRATED CIRCUITS TECHNOLOGY, VOLS 1- 3, PROCEEDINGS Vol. 19 ( 4 ) page： 2297 - 2300 2004

Language：English Publishing type：Research paper (international conference proceedings) Publisher：IEEE

Classical transport and the magneto-transport of the two-dimensional electron gas (2DEG) in modulation-doped AlxGa1-xN/GaN heterostructures have been investigated. In magnetotransport measurements at low temperatures and high magnetic fields, the strong Shubnikov-de Hass (SdH) oscillations with the double periodicity is clearly observed, indicating the 2DEG occupation of the double subbands in the triangular quantum well at the heterointerfaces. Based on the observation of the SdH oscillation with double periodicity, the sheet concentrations and the mobilities of the 2DEG in the first and the second subbands, magnetointersubband scattering (MIS) oscillations of the 2DEG, and the spin splitting of the 2DEG in the quantum well at the heterointerfaces have been studied and discussed.

Fabrication and optical properties of GaN micro-prism array on an Si substrate Reviewed

A. Nishioka, Y. Honda, N. Sawaki

Proc. of Int. Conf. on Electrical Engineering 2004 Vol. 3-1 page： 297-300 2004

Optical spectra of GaN/InGaN/GaN MQW structure grown on a (1-101) GaN facet Reviewed

EH Kim, T Narita, Y Honda, N Sawaki

5TH INTERNATIONAL SYMPOSIUM ON BLUE LASER AND LIGHT EMITTING DIODES, PROCEEDINGS Vol. 1 ( 10 ) page： 2512 - 2515 2004

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-V C H VERLAG GMBH

An InGaN/GaN MQW waveguide was fabricated on a (1-101) facet of MOVPE GaN on a 7 degree off oriented (001)Si substrate. Because of the low growth rate on the facet, we achieved uniform layers with less dislocation density and superior flatness. The optical gain of the stripe structure as a waveguide was analyzed at room temperature. It was found that the optical gain was as high as -20 cm(-1) at a low excitation intensity of 4 kNV/cm(2) even for the photoluminescence peak wavelength of the quantum well. The high optical gain demonstrate the high optical quality of the MQW grown on the facet structure.

DOI： 10.1002/pssc.200405039

Growth of thick AlGaN by metalorganic-hydride vapor phase epitaxy Reviewed

KH Kim, JY Yi, HJ Lee, M Yang, HS Ahn, CR Cho, SW Kim, SC Lee, Y Honda, M Yamaguchi, N Sawaki

5TH INTERNATIONAL SYMPOSIUM ON BLUE LASER AND LIGHT EMITTING DIODES, PROCEEDINGS Vol. 1 ( 10 ) page： 2474 - 2477 2004

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-V C H VERLAG GMBH

The growth of a thick AlGaN is performed on Al(2)O(3) substrate by metalorganic vapor phase epitaxyhydride vapor phase epitaxy (MOVPE-HVPE) combined system. Thin AIN or GaN layer is grown on a substrate by MOVPE growth method with the conventional manner but in a hot-wall chamber and followed by the HVPE growth of a thick AlGaN in the same chamber. For the growth of a AlGaN layer, NH(3) and aluminum-gallium chloride formed by HCl which is flown over metallic Ga mixed with Al are used as aluminum-gallium and nitrogen sources. The peak of the cathodoluminescence (CL) spectrum of the thick AlGaN is shown at the wavelength of 354 nm. This suggests that the metallic Ga mixed with Al can be used as a group III source material in the HVPE growth of the AlGaN. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Wemheim.

DOI： 10.1002/pssc.200405020

Infrared reflectance in GaN/AlGaN triangular stripes grown on Si(111) substrates by MOVPE Reviewed

M Mizushima, T Kato, Y Honda, N Yamaguchi, N Sawaki

JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. 42 ( Supp. issue 2 ) page： S750 - S752 2003.2

Language：English Publishing type：Research paper (scientific journal) Publisher：KOREAN PHYSICAL SOC

Infrared reflectance spectroscopy was applied to the GaN/AlGaN triangular stripes grown on a Si(111) substrate by selective area metalorganic vapor phase epitay. Because of the triangular shape of tile GaN, which worked itself as a prism. we could detect the local vibration modes of Si-N. N-H-2, Si-H, and Si-O,bonds near the GaN/Si interface with high sensitivity.

Photoluminescence properties of a self-doped GaN layer grown on Si substrate Reviewed

KH Kim, H Kim, M Yang, HS Ahn, SN Yi, N Kameshiro, Y Honda, M Yamaguchi, N Sawaki

JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. 42 ( Supp. issue 2 ) page： S219 - S221 2003.2

Language：English Publishing type：Research paper (scientific journal) Publisher：KOREAN PHYSICAL SOC

Photoluminescence (PL) spectra of self-doped GaN were investigated at 77 K. The AlGaN/GaN heterostructure was selectively grown by metal-organic vapor phase epitaxy (MOVPE) on a (111) etched facet of 7 off Si (001) substrate, A peak was observed at 78.1 meV below the band edge peak at 77 K but disappeared at 300 K. The peak depends strongly on varying input power intensity. This peak might originate from the self-doped (SD) layer formed by diffusion of impurities front SiO2 and/or Si substrate.

Optical characteristics of the AlGaN/GaN/AlGaN waveguide grown on (111)Si substrate Reviewed

H Kim, KH Kim, M Yang, HS Ain, SN Yi, T Narita, Y Honda, M Yamaguchi, N Sawaki

JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. 42 page： S622 - S624 2003.2

Language：English Publishing type：Research paper (scientific journal) Publisher：KOREAN PHYSICAL SOC

Optical characteristics of the AlGaN/CaN/AlGaN heterostructure waveguide grown on Si substrate are estimated by photoluminescence (PL) measurement. The sample wads selectively grown as triangular striped structures by metal organic vapor phase epitaxy (MOVPE). We have studied the dependence of PL characteristics of the waveguide structures on the variation of input power position. Two main peaks related to different facet's in the waveguide structures were observed.

HVPE growth of a thick GaN layer on a GaN templated (111) Si substrate Reviewed

Y. Nishimura, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 0 ( 7 ) page： 2506-2510 2003

The surface diffusion of Ga on an AlGaN/GaN facet structure in the MOVPE growth Reviewed

T. Narita, T. Hikosaka, Y. Honda, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 0 ( 7 ) page： 2154-2158 2003

Optical Characteristics of the AlGaN/GaN/AlGaN Waveguide Grown on (111) Si Substrate Reviewed

H. Kim, K. H. Kim, M. Yang, H. S. Ahn, S. N. Yi, T. Narita, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Kor. Phys. Soc. Vol. 42 page： S622-S624 2003

The compositional non-uniformity in an AlGaN capping layer of AlGaN/GaN pyramid grown on a (111) Si substrate by selective MOVPE Reviewed

Y. Honda, M. Torikai, T. Nakamura, Y. Kuroiwa, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 0 ( 7 ) page： 2043-2046 2003

Infrared Reflectance in GaN/AlGaN Triangular Stripes Grown on Si(111) Substrates by MOVPE Reviewed

M. Mizushima, T. Kato, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Kor. Phys. Soc. Vol. 42 ( Supp. issue 2 ) page： S750-S752 2003

Photoluminescence Properties of a Self-Doped GaN Layer Grown on Si Substrate Reviewed

K. H. Kim, H. Kim, M. Yang, H. S. Ahn, S. N. Yi, N. Kameshiro, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Kor. Phys. Soc. Vol. 42 ( Supp. issue 2 ) page： S219-S221 2003

HVPE growth of a thick GaN layer on a GaN templated (111)Si substrate Reviewed

Y Nishimura, Y Honda, M Yamaguchi, N Sawaki

5TH INTERNATIONAL CONFERENCE ON NITRIDE SEMICONDUCTORS (ICNS-5), PROCEEDINGS Vol. 0 ( 7 ) page： 2506 - 2510 2003

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-VCH, INC

The hydride vapour phase epitaxial (HVPE) growth of thick GaN was attempted on a (111) Si substrate. In order to avoid fatal damage to the substrate surface in the HCl ambient and to get a high growth rate, a two-step growth method was adopted; the first low growth rate step with low HCl flow rate followed by a second high growth rate step. As the result, a flat surface of thick GaN was obtained. The full width at half maximum of the photoluminescence spectra at 77 K was as narrow as 17.7 meV. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

DOI： 10.1002/pssc.200303512

The surface diffusion of Ga on an AlGaN/GaN facet structure in the MOVPE growth Reviewed

T Narita, T Hikosaka, Y Honda, M Yamaguchi, N Sawaki

5TH INTERNATIONAL CONFERENCE ON NITRIDE SEMICONDUCTORS (ICNS-5), PROCEEDINGS Vol. 0 ( 7 ) page： 2154 - 2158 2003

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-VCH, INC

The growth of a trapezoidal AlGaN/GaN heterostructure was attempted on a (111) Si substrate by selective area metal organic vapour phase epitaxy. On the trapezoidal sample we found that the manner of ridge growth is different in GaN growth from that in AlGaN growth. Analysing the thickness and composition with scanning electron microscopy (SEM), reflection electron microscopy (REM) and cathode luminescence (CL) spectroscopy, the diffusion length of Ga chemical species on the (0001) AlGaN surface was determined. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/pssc.200303511

The compositional non-uniformity in an AlGaN capping layer of AlGaN/GaN pyramid grown on a (111)Si substrate by selective MOVPE Reviewed

Y Honda, M Torikai, T Nakamura, Y Kuroiwa, M Yamaguchi, N Sawaki

5TH INTERNATIONAL CONFERENCE ON NITRIDE SEMICONDUCTORS (ICNS-5), PROCEEDINGS Vol. 0 ( 7 ) page： 2043 - 2046 2003

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-VCH, INC

The alloy composition of an AlGaN film grown on a GaN hexagonal pyramidal structure is studied by cathode luminescence spectroscopy. The samples are made by selective area growth mode of metal organic vapour phase epitaxy (MOVPE). It was found that the Al composition is lower than the nominal composition at the bottom of the pyramid, while it was higher than the nominal composition near the top of the pyramid. Analysing the composition as a function of the position on the facets, the diffusion length of Ga was estimated to be 310 mn and 915 nm on the (0001) and (1 (1) over bar 01) facet, respectively. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/pssc.200303373

The surface diffusion of Ga on an AlGaN/GaN facet structure in the MOVPE growth Reviewed

Tetsuo Narita, Toshiki Hikosaka, Yoshio Honda, Masahito Yamaguchi, Nobuhiko Sawaki

Physica Status Solidi C: Conferences ( 7 ) page： 2154 - 2158 2003

Language：English Publishing type：Research paper (international conference proceedings)

DOI： 10.1002/pssc.200303511

Transmission Electron Microscopy Study of the Microstructure in Selective-Area-Grown GaN and an AlGaN/GaN Heterostructure on a 7-Degree Off-Oriented (001) Si Substrate Reviewed

Tanaka Shigeyasu, Honda Yoshio, Kameshiro Norifumi, IWASAKI Ryuta, SAWAKI Nobuhiko, TANJI Takayoshi

Japanese journal of applied physics. Pt. 2, Letters Vol. 41 ( 7 ) page： L846 - L848 2002.7

Growth of (1(1)over-bar-01) GaN on a 7-degree off-oriented (001)Si substrate by selective MOVPE Reviewed

Y Honda, N Kameshiro, M Yamaguchi, N Sawaki

JOURNAL OF CRYSTAL GROWTH Vol. 242 ( 1-2 ) page： 82 - 86 2002.7

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The selective growth of wurtzile GaN was performed by MOVPE on (1 1 1) facets on a patterned 7-degree off-oriented (0 0 1) silicon substrate, which had been prepared by anisotropic etching with KOH solution. The c-axis of the GaN was along the [1 1 1] axis of the silicon. At an early growth stage, the shape of the crystal grown selectively was a stripe having truncated triangular cross-section and its (1 (1) over bar 0 1) facet was parallel to the substrate surface. After a sufficient growth duration, the stripes coalesced with each other and a GaN film with a flat (1 (1) over bar 0 1) surface was achieved. (C) 2002 Elsevier Science B.V. All rights reserved.

Transmission electron microscopy study of the microstructure in selective-area-grown GaN and an AlGaN/GaN heterostructure on a 7-degree off-oriented (001) Si substrate Reviewed

S Tanaka, Y Honda, N Kameshiro, R Iwasaki, N Sawaki, T Tanji

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS Vol. 41 ( 7B ) page： L846 - L848 2002.7

Language：English Publishing type：Research paper (scientific journal) Publisher：INST PURE APPLIED PHYSICS

We have studied the microstructure in a (1 (1) over bar 01) GaN triangular bar and an AlGaN/GaN heterostructure formed on top of it by means of transmission electron microscopy. The nitride triangular bar was selectively grown on a 7-degree off-oriented (001) Si substrate by metalorganic vapor phase epitaxy. Convergent beam electron diffraction was used to determine the lattice polarity. Threading dislocations were generated near the, interface between the unmasked (111) facet of the Si and the nitride. These dislocations bend towards either the (1 (1) over bar 01) facet or the interface between the GaN and masked ((1) over bar(1) over bar1) Si, and thread through to the facet or the interface. Dislocations were observed at the AlGaN/GaN interface. It is shown that the growth proceeded predominantly in the [0001] direction of the nitride with Ga-terminated polarity.

DOI： 10.1143/JJAP.41.L846

Growth of a GaN crystal free from cracks on a (111)Si substrate by selective MOVPE Reviewed

Y Honda, Y Kuroiwa, M Yamaguchi, N Sawaki

JOURNAL OF CRYSTAL GROWTH Vol. 242 ( 1-2 ) page： 77 - 81 2002.7

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The selective growth of wurtzite GaN was performed on a (1 1 1)silicon substrate by metalorganic vapor phase epitaxy. By limiting the size of GaN to the area of 0.5 mm x 0.5 mm, a single GaN crystal without cracks was obtained. As a result, the full-width at half-maximum of the (0 0 0 4) X-ray-rocking curve as well as that of the band edge emission were much reduced as compared to the samples grown by a conventional method. (C) 2002 Elsevier Science B.V. All rights reserved.

Selective MOVPE Growth and Optical Properties of a GaN/AlGaN Stripe Structure on (111)Si Substrate Reviewed

NARITA Tetsuo, KATO Tomonobu, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

IEICE technical report. Electron devices Vol. 102 ( 114 ) page： 25 - 28 2002.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

A trapezoidal stripe structure and GaN/AlGaN heterostructure were fabricated on a (111)Si substrate by selective area metalorganic vapor phaseepitaxy(SAG-MOVPE). The stripe was made of (11^^-01) side facets and (0001) face at the top. The cathode luminescence spectra at 4.0K exhibited several DAP emission from the AlGaN alloy. It was shown that the optical spectra depend on the thickness of the film on the facets. This suggests that the strain at the heterointerface modifies the growth mode on the facet.

Selective MOVPE Growth and Optical Properties of a GaN/AlGaN Stripe Structure on (111)Si Substrate Reviewed

NARITA Tetsuo, KATO Tomonobu, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

Technical report of IEICE. LQE Vol. 102 ( 117 ) page： 25 - 28 2002.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

A trapezoidal stripe structure and GaN/AlGaN heterostructure were fabricated on a (111)Si substrate by selective area metalorganic vapor phaseepitaxy(SAG-MOVPE). The stripe was made of (1101) side facets and (0001) face at the top. The cathode luminescence spectra at 4.0K exhibited several DAP emission from the AlGaN alloy. It was shown that the optical spectra depend on the thickness of the film on the facets. This suggests that the strain at the heterointerface modifies the growth mode on the facet.

Growth of GaN/AlGaN pyramid arrays on a Si substrate by MOVPE Reviewed

TORIKAI Masayuki, KATO Tomonobu, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

Technical report of IEICE. LQE Vol. 102 ( 117 ) page： 21 - 24 2002.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

MOVPE growth of a GaN/Al_xGa_1-xN hexagonal pyramid array was attempted on a (111)Si substrate. On a truncated GaN pyramidal structure, an Al_xGa_1-xN film was deposited. It was found that the Al composition is a strong function of the position on the facets. At the top of the pyramid, it was higher than that at the bottom. The phenomenon is attributed to the different diffusion coefficients of Al and Ga chemical species on the surface. In case of the AlN film, the CL spectrum at 4.2 K for the C-surface exhibited a strong peak 218nm. However, we found an array of pits of which structure reflecting the hexagonal structure of the facet.

Growth of GaN/AlGaN pyramid arrays on a Si substrate by MOVPE Reviewed

TORIKAI Masayuki, KATO Tomonobu, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

IEICE technical report. Electron devices Vol. 102 ( 114 ) page： 21 - 24 2002.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

MOVPE growth of a GaN/Al_xGa_<1-x>N hexagonal pyramid array was attempted on a (111)Si substrate. On a truncated GaN pyramidal structure, an Al_xGa_<1-x> film was deposited. It was found that the Al composition is a strong function of the position on the facets. At the top of the pyramid, it was higher than that at the bottom. The phenomenon is attributed to the different diffusion coefficients of Al and Ga chemical species on the surface. In case of the AIN film, the CL spectrum at 4.2 K for the C-surface exhibited a strong peak 218nm. However, we found an array of pits of which structure reflecting the hexagonal structure of the facet.

Growth of (1-101) GaN on a 7 degrees off axis (001) Si substrate Reviewed

KAMESHIRO Norifumi, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

IEICE technical report. Component parts and materials Vol. 102 ( 78 ) page： 27 - 31 2002.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

The GaN grown on a (111) Silicon substrate has, usually, many cracks because of the large mismatch of the thermal expansion coefficients. We have proposed a method to reduce the strain due to this large mismatch by inclining the C-axis. On a 7 degrees off axis (001) Silicon substrate (111) facets are made by anisotropic etching in KOH solution. On this facet we grew GaN selectively, of which (1-101) surface is parallel to the Silicon substrate. Moreover, we fabricated AlGaN/GaN heterostructures on the (1-101) GaN.

Growth of (1-101) GaN on a 7 degrees off axis (001) Si substrate Reviewed

KAMESHIRO Norifumi, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

IEICE technical report. Electron devices Vol. 102 ( 76 ) page： 27 - 31 2002.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Growth of (1-101) GaN on a 7 degrees off axis (001) Si substrate Reviewed

KAMESHIRO Norifumi, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

Technical report of IEICE. SDM Vol. 102 ( 80 ) page： 27 - 31 2002.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Growth of GaN free from cracks on a (111)Si substrate by selective metalorganic vapor- phase epitaxy Reviewed

KUROIWA Yousuke, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

IEICE technical report. Component parts and materials Vol. 102 ( 78 ) page： 15 - 19 2002.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

The selective metalorganic vapor-phase epitaxy of wurtzite GaN was performed on a (111) silicon substrate using SiO_2 grid mask pattern. Though rigde growth arose at egde region of the mask, GaN films free from cracks were achived. The full width at half maximum of the (0004) X-ray rocking curve was as narrow as 388 arcsec and that of the band edge emission of photoluminescence at 77K was 18.6 meV. I-V characteristics of a GaN/AlGaN/Si diode shows low resistance ohmic behavior, and The photocurrent spectra show existence of an amorphous Si layer at AlGaN/Si interface.

Growth of GaN free from cracks on a (111)Si substrate by selective metalorganic vapor-phase epitaxy Reviewed

KUROIWA Yousuke, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

IEICE technical report. Electron devices Vol. 102 ( 76 ) page： 15 - 19 2002.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Growth of GaN free from cracks on a (111)Si substrate by selective metalorganic vapor-phase epitaxy Reviewed

KUROIWA Yousuke, HONDA Yoshio, YAMAGUCHI Masahito, SAWAKI Nobuhiko

Technical report of IEICE. SDM Vol. 102 ( 80 ) page： 15 - 19 2002.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Fabrication of GaN/AlGaN heterostructures on a (111)Si substrate by selective MOVPE Reviewed

T Kato, Y Honda, M Yamaguchi, N Sawaki

JOURNAL OF CRYSTAL GROWTH Vol. 237 ( 2 ) page： 1099 - 1103 2002.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Growth of GaN/AlGaN heterostructure and quantum well (QW) on the (1 (1) over bar 0 1) side facets of truncated triangular GaN which is grown on a (1 1 1) silicon substrate is demonstrated for the first time. The cathode luminescence image showed that the composition of AlGaN is not uniform on the side facets, but the photoluminescence spectra exhibited clear peaks, which were attributed to the GaN QW embedded between AlGaN cladding layers. (C) 2002 Elsevier Science B.V. All rights reserved.

Growth of GaN free from cracks on a (111)Si substrate by selective metalorganic vapor-phase epitaxy Reviewed

Y Honda, Y Kuroiwa, M Yamaguchi, N Sawaki

APPLIED PHYSICS LETTERS Vol. 80 ( 2 ) page： 222 - 224 2002.1

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

The selective metalorganic vapor-phase epitaxy of wurtzite GaN was performed on a (111) silicon substrate using SiO2 grid mask pattern. Within window regions of (0.2-0.5) mmx(0.2-0.5) mm, GaN films free from cracks were achieved. The full width at half maximum of the (0004) X-ray rocking curve was as narrow as 388 arcs and that of the band edge emission was 18.6 meV at 77 K. The band edge emission peak energy was redshifted. The redshift is reduced slightly in a sample grown on small windows. This suggests that the biaxial strain due to the thermal expansion coefficient mismatch is partly relaxed on small windows. (C) 2002 American Institute of Physics.

Transmission Electron Microscopy Study of the Microstructure in Selective-Area-Grown GaN and an AlGaN/GaN Heterostructure on a 7-Degree Off-Oriented (001) Si Substrate. Reviewed

Growth of GaN free from cracks on a (111) Si substrate by selective metalorganic vapor-phase epitaxy Reviewed

Y. Honda, Y. Kuroiwa, M. Yamaguchi, and N. Sawaki

Appl. Phys. Lett Vol. 80 ( 2 ) page： 222-224 2002

Fabrication of GaN/AlGaN heterostructures on a (111) Si substrate by selective MOVPE Reviewed

T. Kato, Y. Honda, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 237-239 ( 2 ) page： 1099-1103 2002

Growth of GaN crystal free from cracks on a (111) Si substrate by selective MOVPE Reviewed

Y. Honda, Y. Kuroiwa, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 242 ( 1-2 ) page： 77-81 2002

Transmission electron microscopy study of the microstructure in selective-area-grown GaN and an AlGaN/GaN heterostructure on a 7-degree off-oriented (001) Si substrate Reviewed

S. Tanaka, Y. Honda, N. Kameshiro, R. Iwasaki, N. Sawaki, and T. Tanji

Jpn. J. Appl. Phys. Vol. 41 ( 7B ) page： L846-L848 2002

HVPE Growth of GaN on a GaN Templated (111) Si Substrate Reviewed

Y. Honda, T. Ishikawa, Y. Nishimura, M. Yamaguchi, and N. Sawaki

phys. stat. sol. (c) Vol. 0 ( 1 ) page： 107-111 2002

Fabrication of GaN/AlGaN MQW on (1-101) facet of wurtzite GaN grown on a (111) Si substrate by selective MOVPE Reviewed

T. Kato, Y. Honda, M. Yamaguchi, N. Sawaki

Inst. Phys. Conf. Ser. Vol. 170 page： 789-794 2002

Growth of (1-101) GaN on a 7-degree off-oriented (001) Si substrate by selective MOVPE Reviewed

Y. Honda, N. Kameshiro, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 242 ( 1-2 ) page： 82-86 2002

Tanaka Shigeyasu, Honda Yoshio, Kameshiro Norifumi, Iwasaki Ryuta, Sawaki Nobuhiko, Tanji Takayoshi

Japanese Journal of Applied Physics Vol. 41 ( 7 ) page： L846 - L848 2002

Fabrication of GaN/AlGaN MQW on (1-101) facet of wurtzite GaN grown on a (111) Si substrate by selective MOVPE Reviewed

T Kato, Y Honda, M Yamaguchi, N Sawaki

COMPOUND SEMICONDUCTORS 2001 Vol. 170 ( 170 ) page： 789 - 794 2002

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

A GaN/AlGaN multiple quantum well (MQW) is fabricated on (1-101) facet of wurtzite GaN grown on a (111) Si substrate by selective MOVPE. The cathode luminescence (CL) and photoluminescence (PL) spectra exhibit subsidiary peak adjacent to the main peak due to GaN truncated triangular structure, which is attributed to the GaN/AlGaN MQW. The CL images indicate compositional non-uniformity of AlGaN cladding layer due to the different diffusion lengths of Al and Ga species on the surface.

HVPE growth of GaN on a GaN templated (111) Si substrate Reviewed

Y Honda, T Ishikawa, Y Nishimura, M Yamaguchi, N Sawaki

INTERNATIONAL WORKSHOP ON NITRIDE SEMICONDUCTORS, PROCEEDINGS Vol. 0 ( 1 ) page： 107 - 111 2002

Language：English Publishing type：Research paper (international conference proceedings) Publisher：WILEY-V C H VERLAG GMBH

The hydride vapor phase epitaxial (HVPE) growth of GaN was attempted on a (111) Si substrate. In order to suppress the chemical reaction of the Si at high temperatures, the surface of the substrate was covered by a thin SiO2 film or GaN pyramids which were grown by selective metal-organic vapor phase epitaxy (MOVPE). The GaN pyramids served as the seeds for the following HVPE growth of GaN. Uniform layer of 12 mum thick wurtzite GaN was achieved successfully. The full width at half maximum (FWHM) of (0004) X-ray rocking curve was 450 arcsec. The cathode luminescence (CL) spectra at 4.2 K exhibited a strong band edge emission peak of which FWHM was as broad as 30.3 meV.

Selective area growth of GaN microstructures on patterned (111) and (001) Si substrates Reviewed

Y Honda, Y Kawaguchi, Y Ohtake, S Tanaka, M Yamaguchi, N Sawaki

JOURNAL OF CRYSTAL GROWTH Vol. 230 ( 3-4 ) page： 346 - 350 2001.9

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Selective MOVPE growth of GaN microstructure on silicon substrates has been investigated using SiO2 mask having circular or stripe window. In case of (001)substrate, grooves with (1 1 1) facets at the sides were made by using the etching anisotropy of a KOH solution. On the (1 1 1) facets of patterned silicon substrate (or on the as opened window region of (1 1 1) substrate), growth of wurtzite GaN was performed, of which the c-axis is oriented along the (1 1 1) axis of silicon. The photoluminescence and X-ray diffraction analysis were performed to characterize the single crystal to reveal the effect of the growth conditions of the intermediated layer and the microstructure. (C) 2001 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0022-0248(01)01244-1

Structural characterization of GaN laterally overgrown on a (111)Si substrate Reviewed Open Access

S Tanaka, Y Honda, N Sawaki, M Hibino

APPLIED PHYSICS LETTERS Vol. 79 ( 7 ) page： 955 - 957 2001.8

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

Using transmission electron microscopy, we have characterized defect structures in laterally overgrown GaN crystals, grown directly on SiO2 stripe-patterned (111)Si substrates by metalorganic vapor phase epitaxy using AlGaN as an intermediate layer. The width and the period of the stripe windows were nominally 1 and 2 mum, respectively. The average threading dislocation density for a completely coalesced 2-mum-thick GaN crystal obtained on the [11 (2) over tilde]-oriented stripe-patterned substrate was similar to 2x10(9) cm(-2). The reduction in threading dislocation density is a consequence of the lateral growth and dislocation reactions at the coalesced front of the mask. On the other hand, valleys and pits tend to remain on the mask during the growth on the [1 (1) over bar0]-oriented stripe-patterned substrate. Cracks were present in both crystals. (C) 2001 American Institute of Physics.

DOI： 10.1063/1.1394716

Selective growth of GaN/AlGaN microstructures by metalorganic vapor phase epitaxy Reviewed

T Kato, Y Honda, Y Kawaguchi, M Yamaguchi, N Sawaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS Vol. 40 ( 3B ) page： 1896 - 1898 2001.3

Language：English Publishing type：Research paper (scientific journal) Publisher：INST PURE APPLIED PHYSICS

A GaN/AlGaN double heterostructure was fabricated on the (1 (1) over bar 01) facets of a GaN triangular structure prepared by selective area growth by metalorganic vapor phase epitaxy. The photoluminescence (PL) and cathode luminescence (CL) spectra were investigated to characterize the structure. It was found that the PL peak wavelength due to the GaN quantum well is dependent on the well thickness, However. the Al composition of the AlGaN layer is dependent on the position on the (1 (1) over bar 01) facet. The anomalous gradient of the composition is attributed to the difference in the diffusion coefficients of At and Ga on the surface.

DOI： 10.1143/JJAP.40.1896

Fabrication of GaN dots array on Si substrate by selective area growth method Reviewed

YAMAGUCHI Masahito, HONDA Yoshio, SAWAKI Nobuhiko

Technical report of IEICE. SDM Vol. 100 ( 643 ) page： 25 - 30 2001.2

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

We have fabricated sub-micron GaN dots array on(111)Si substrate by metal organic vapor phase epitaxy(MOVPE)selective area growth. The SiO_2 mask for the selective area growth was prepared with electron beam lithography system and the circle window diameter of the mask was less than 250 nm. The bottom and top surface size of the fabricated GaN dots was about 250 nm and 50 nm, respectively. In comparison with the GaN dots grown on sapphire substrate, the shape of the facet was found to be clear. The optical properties in the GaN dot on Si substrate are relatively good. Therefore, the(111)Si substrate is suitable for the fabrication of the GaN quantum dots.

Fabrication of GaN micro-structures on (111) Si by selective area growth by MOVPE Reviewed

Selective growth of GaN/AlGaN microstructures by metalorganic vapor phase epitaxy Reviewed

T. Kato, Y. Honda, Y. Kawaguchi, M. Yamaguchi, and N. Sawaki

Jpn. J. Appl. Phys. Vol. 40 ( 3B ) page： 1896-1898 2001

Structural characterization of GaN laterally overgrown on a (111)Si substrate Reviewed Open Access

S. Tanaka, Y. Honda, N. Sawaki, and M. Hibino

Appl. Phys. Lett Vol. 79 ( 7 ) page： 955-957 2001

Selective area growth of GaN microstructures on petterned (111) and (001) Si substrate Reviewed

Y. Honda, Y. Kawaguchi, Y. Ohtake, M. Yamaguchi, and N. Sawaki

J. Cryst. Growth Vol. 230 ( 3-4 ) page： 346-350 2001

HONDA Y., OHTAKE Y., KAWAGUCHI Y., YAMAGUCHI M., SAWAKI N.

IEICE technical report. Electron devices Vol. 99 ( 616 ) page： 21 - 28 2000.2

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

Selective area growth(SAG)of stripe structure and hexagonal pyramids of GaN on a(111)Si substrate is studied with AlGaN intermediate layer. The crystalinity is much improved by the SAG as compared to that due to a conventional method. It is demonstrated that the formation process of the intermediate layer is the key issue to improve the optical properties as well as the crystalinity.

Selective growth of GaN microstructures on (111) facets of a (001)Si substrate by MOVPE Reviewed

Y. Honda, Y. Kawaguchi, T. Kato, M. Yamaguchi, and N. Sawaki

IPAP Conf. Series Vol. 1 page： 304-307 2000

Selective growth of GaN microstructures on (111) facets of a (001) Si substrate by MOVPE Reviewed

Y Honda, Y Kawaguchi, T Kato, M Yamaguchi, N Sawaki

PROCEEDINGS OF THE INTERNATIONAL WORKSHOP ON NITRIDE SEMICONDUCTORS Vol. 1 page： 302 - 307 2000

Language：English Publishing type：Research paper (international conference proceedings) Publisher：INST PURE APPLIED PHYSICS

The selective growth of wurtzite GaN was performed by MOVPE on (111) facets on a patterned (001) silicon substrate, which were fabricated by anisotropic etching with KOH solution using an SiO2 mask. The c-axis of the GaN was along the (111) axis of silicon and the shape of the crystal was a stripe having triangular cross-section. It was found the growth along < 000 (1) over bar > was not prominent and the growth rate was lower than that for the (1 (1) over bar 01) facet. As the result, lateral overgrowth on the SiO2 mask was substantially refrained. By a surface treatment with nitric acid, the growth of polycrystalline on bare (001) surface was completely suppressed keeping the growth on adjacent (111) facets.

DOI： 10.1002/(SICI)1521-396X(199911)176:1<557::AID-PSSA557>3.0.CO;2-2

Selective growth of cubic GaN on patterned GaAs(100) substrates by metalorganic vapor phase epitaxy Reviewed

Jun Wu, M. Kudo, A. Nagayama, H. Yaguchi, K. Onabe, Y. Shiraki

Physica Status Solidi (A) Applied Research Vol. 176 ( 1 ) page： 557 - 560 1999.11

Language：English Publishing type：Research paper (scientific journal)

Selective growth of cubic GaN on patterned GaAs substrates was studied. The structural and morphological properties of cubic GaN are very dependent on the orientation of the mask stripes. In the case of window stripe opening along [011] direction, (111)B facets were clearly observed in all the samples, regardless of the different growth time. Both X-ray diffraction and photoluminescence measurements showed that the hexagonal phase GaN was considerably incorporated in the cubic GaN layer, indicating that the hexagonal GaN is easily constructed along the (111)B facet. In contrast, window stripes opening along [01-1] direction resulted in the formation of (311)A facets and subsequently a relatively flat surface occurred as the growth proceeded. Strong emission peaks of cubic GaN were observed in the photoluminescence spectra.

Crystal orientation fluctuation of epitaxial-lateral-overgrown GaN with W mask and SiO2 mask observed by transmission electron diffraction and X-ray rocking curves Reviewed

Y Honda, Y Iyechika, T Maeda, H Miyake, K Hiramatsu, H Sone, N Sawaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS Vol. 38 ( 11B ) page： L1299 - L1302 1999.11

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN J APPLIED PHYSICS

Fluctuation of the crystal orientation of epitaxial-lateral-overgrown (ELO) GaN with a tungsten (W) mask is compared to that with a SiO2 mask by means of selected-area transmission electron diffraction (TED) and X-ray rocking curves (XRCs). XRCs of (0004) reflection exhibited three peaks for ELO-GaN on a SiO2 mask, and were confirmed to originate from domains of different c-axis orientation by TED. On the other hand, fluctuation of the c-axis was not observed for ELO-GaN with a W mask. These results indicate that the crystalline quality of ELO-GaN with a W mask is better than that with a SiO2 mask.

DOI： 10.1143/JJAP.38.L1299

Selective Area Growth of GaN on Stripe-Patterned (111)Si Substrate by Metalorganic Vapor Phase Epitaxy Reviewed

Y. Kawaguchi, Y. Honda, M. Yamaguchi, N. Sawaki, and K. Hiramatsu

Phys. Stat. Sol. (a) Vol. 176 page： 553-556 1999

Selective area growth (SAG) and epitaxial lateral overgrowth (ELO) of wurtzite GaN on (111) Si substrate by metalorganic vapor phase epitaxy Reviewed

Y. Kawaguchi, Y. Honda, M. Yamaguchi, K. Hiramatsu, and N. Sawaki

Inst. Phys. Conf. Ser. Vol. 162 page： 687-692 1999

Selective area growth (SAG) and epitaxial lateral overgrowth (ELO) of wurtzite GaN on (111) Si substrate by metalorganic vapor phase epitaxy Reviewed

Y Kawaguchi, Y Honda, M Yamaguchi, K Hiramatsu, N Sawaki

COMPOUND SEMICONDUCTORS 1998 Vol. 162 ( 162 ) page： 687 - 692 1999

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Selective area growth (SAG) of GaN on a (111) Si substrate using AlGaN as an intermediate layer by Metalorganic Vapor Phase Epitaxy (MOVPE) was studied. By optimizing the growth conditions, truncated hexagonal pyramids of GaN were obtained, and GaN polycrystals could not be observed on SiO2 masks. Cathodoluminescence (CL) spectra at 148 K showed that the near-band-edge emission peak shifts towards low energy side in comparison with that of a GaN layer grown on a (0001) sapphire substrate. This suggests that the tensile strain due to the heteroepitaxy is given in the GaN pyramid on the Si substrate in contrast to the compressive strain of the GaN layer on the sapphire substrate.

Selective area growth of GaN on Si substrate using SiO2 mask by metalorganic vapor phase epitaxy Reviewed

Y Kawaguchi, Y Honda, H Matsushima, M Yamaguchi, K Hiramatsu, N Sawaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS Vol. 37 ( 8B ) page： L966 - L969 1998.8

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN J APPLIED PHYSICS

Selective area growth (SAG) of GaN on (111) Si substrate was studied using AlGaN as an intermediate layer. A hexagonal dot with a (0001) plane on the top and of a 5 mu m or a submicron size was obtained using a patterned dot structure of silicon dioxide (SiO2) mask. The facet structure revealed that the < 1120 > axis of hexagonal GaN is parallel to the < 110 > axis of the Si substrate. The cathodoluminescence (CL) spectrum at 133 K exhibited a strong near-band-edge emission hand for the submicron dots, which suggests excellent crystallinity. Epitaxial lateral overgrowth (ELO) of GaN on the Si substrate is demonstrated.