研究者詳細 - 天野　浩

論文 - 天野　浩

分割表示 851 件中 181 - 200 件目／全件表示 >>

Oxygen Incorporation Kinetics in Vicinal <i>m</i>(10-10) Gallium Nitride Growth by Metal-Organic Vapor Phase Epitaxy

Yosho, D; Shintaku, F; Inatomi, Y; Kangawa, Y; Iwata, JI; Oshiyama, A; Shiraishi, K; Tanaka, A; Amano, H

PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS 14 巻 ( 6 ) 頁： 2000142 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physica Status Solidi - Rapid Research Letters

The oxygen incorporation kinetics of vicinal m(10−10) gallium nitride (GaN) growth during metal-organic vapor phase epitaxy is clarified using a diffusion equation-based approach that incorporates diffusion potentials obtained by large-scale density functional theory (DFT) calculations. A diffusion model based on the Burton, Cabrera and Frank (BCF) theory is proposed, and then, the oxygen concentration in the epitaxial films is calculated quantitatively. The calculation results agree with the experimental tendency that the oxygen concentration in the −c 5° off m-GaN epilayers is lower than that in the +c 5° off m-GaN epilayers. Then, the off-angle dependence of oxygen incorporation in vicinal m-GaN growth is predicted.

DOI： 10.1002/pssr.202000142

Web of Science

Scopus

Vertical GaN-on-GaN Schottky Diodes as α-Particle Radiation Sensors.

11 巻 ( 5 ) 頁： 519 2020年5月

Improving the Leakage Characteristics and Efficiency of GaN-based Micro-Light-Emitting Diode with Optimized Passivation

Lee, H; Lee, JH; Park, JS; Seong, TY; Amano, H

ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY 9 巻 ( 5 ) 頁： 055001 2020年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ECS Journal of Solid State Science and Technology

We investigated the effect of atomic layer deposition (ALD) Al2O3 (50 nm)/plasma-enhanced chemical vapour deposition (PECVD) SiO2 (250 nm) and PECVD SiO2 (300 nm) passivation layers on the leakage current and efficiency of InGaN-based micro-LEDs with different sizes. Regardless of passivation layers, the leakage current increased with decreasing LED size and increasing reverse bias. Emission microscopy examination showed that with increasing reverse bias, the number of defect-related emission spots and their intensities increased. For the micro-LEDs <50 μm, the emission spots were mainly located at the sidewall regions. Above-10 V, the single PECVD SiO2 passivation layer gave higher leakage current than the double ALD-Al2O3/PECVD-SiO2 layer. The micro-LEDs with the single passivation layer gave the ideality factors of about 2.0, while that with the double layer exhibited values smaller than 2.0. The micro-LEDs with the double passivation layer exhibited external quantum efficiency peaks at lower current density compared to those with the single layer. It was shown that smaller micro-LEDs were more sensitively dependent on the types of the passivation layers. These results exhibit that the ALD-Al2O3/PECVD-SiO2 passivation layer is more effective in suppressing the sidewall damage-induced current than the PECVD-SiO2 layer.

DOI： 10.1149/2162-8777/ab915d

Web of Science

Scopus

Impact of high-Temperature implantation of Mg ions into GaN

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

Japanese Journal of Applied Physics 59 巻 ( 5 ) 頁： 056502 2020年5月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Applied Physics

Magnesium (Mg) ion implantation into gallium nitride (GaN) at 1000 °C is proposed. Since ion implantation and annealing occur simultaneously in high-Temperature implantation, it is considered that Mg ions can be introduced at an appropriate position upon their implantation. GaN vertical diodes implanted with Mg ions were fabricated and current-voltage measurements were performed. As a result, clear rectifying properties were confirmed in a sample that was implanted with Mg ions at 1000 °C and annealed after implantation. However, the sample subjected to Mg ion implantation at RT and annealed after implantation showed no clear rectification. These results show that high-Temperature implantation of Mg ions at 1000 °C reduces Mg ion implantation-induced damage and simultaneously activates Mg ions upon their implantation.

DOI： 10.35848/1347-4065/ab8b3d

Scopus

Computational study of oxygen stability in vicinal m(10-10)-GaN growth by MOVPE

Shintaku F., Yosho D., Kangawa Y., Iwata J.I., Oshiyama A., Shiraishi K., Tanaka A., Amano H.

Applied Physics Express 13 巻 ( 5 ) 頁： 055507 2020年5月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Applied Physics Express

Using density functional calculations, we clarify the oxygen incorporation mechanism in vicinal m-GaN growth by metal-organic vapor-phase epitaxy. We first identify reconstructed structures of 5° off m-GaN toward the ±c directions. Next, we explore preferable sites for oxygen substitution near step edges. We find that oxygen prefers the lower nitrogen site of the step edge on the +c 5° off m-GaN substrate compared with that on the-c 5° off m-GaN substrate. This tendency agrees with recent experimental findings that the oxygen concentration in-c 5° off m-GaN epilayers is lower than that in +c 5° off m-GaN epilayers.

DOI： 10.35848/1882-0786/ab8723

Scopus

Impact of high-temperature implantation of Mg ions into GaN

Takahashi, M; Tanaka, A; Ando, Y; Watanabe, H; Deki, M; Kushimoto, M; Nitta, S; Honda, Y; Shima, K; Kojima, K; Chichibu, SF; Amano, H

JAPANESE JOURNAL OF APPLIED PHYSICS 59 巻 ( 5 ) 2020年5月

Computational study of oxygen stability in vicinal m(10-10)-GaN growth by MOVPE

Shintaku Fumiya, Yosho Daichi, Kangawa Yoshihiro, Iwata Jun-Ichi, Oshiyama Atsushi, Shiraishi Kenji, Tanaka Atsushi, Amano Hiroshi

APPLIED PHYSICS EXPRESS 13 巻 ( 5 ) 2020年5月

Improved Leakage and Output Characteristics of Pixelated LED Array for Headlight application

Lee Sang-Youl, Kang Kiman, Lee Eunduk, Jo Yoomin, Kim Doyub, Oh Jeong-Tak, Jeong Hwan-Hee, Seong Tae-Yeon, Amano Hiroshi

ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY 9 巻 ( 4 ) 頁： 045011 2020年4月

Experimental observation of high intrinsic thermal conductivity of AlN

Cheng Zhe, Koh Yee Rui, Mamun Abdullah, Shi Jingjing, Bai Tingyu, Huynh Kenny, Yates Luke, Liu Zeyu, Li Ruiyang, Lee Eungkyu, Liao Michael E., Wang Yekan, Yu Hsuan Ming, Kushimoto Maki, Luo Tengfei, Goorsky Mark S., Hopkins Patrick E., Amano Hiroshi, Khan Asif, Graham Samuel

PHYSICAL REVIEW MATERIALS 4 巻 ( 4 ) 頁： 044602 2020年4月

Tungsten carbide layers deposited on graphite substrates <i>via</i> a wet powder process as anti-parasitic-reaction coatings for reactor components in GaN growth

Nakamura, D; Kimura, T; Itoh, K; Fujimoto, N; Nitta, S; Amano, H

CRYSTENGCOMM 22 巻 ( 15 ) 頁： 2632 - 2641 2020年4月

Improved Light Output of AlGaInP-Based Micro-Light Emitting Diode Using Distributed Bragg Reflector

Lee, SY; Moon, JH; Moon, YT; Kim, CS; Park, S; Oh, JT; Jeong, HH; Seong, TY; Amano, H

IEEE PHOTONICS TECHNOLOGY LETTERS 32 巻 ( 7 ) 頁： 438 - 441 2020年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE Photonics Technology Letters

We investigated how the performance and reliability of AlGaInP-based red (620 nm) micro-light-emitting diodes (micro-LEDs) (25×17 μ m2) were influenced by the use of n-AlInP ohmic layer and distributed Bragg reflector (DBR). The AlGaAs-based DBR showed reflectivity of 94.9% at 622 nm with a 14 nm-stopband width. The micro-LEDs with n-GaAs gave slightly lower forward voltages by 0.013 - 0.021 V than those with n-Al0.5In0.5P/ n-Al0.6Ga0.4As and nAl0.5In0.5P/DBR. However, the micro-LEDs with n-Al0.5In0.5P/ n-Al0.6Ga0.4As and n-Al0.5In0.5P/DBR gave 61% and 125% higher light output power at 20μ A compared with that with n-GaAs. It was shown that after annealing at 120 °C for 2,000 h, the forward voltage and the light output power at 4.7 A/cm2 of the micro-LEDs with n-Al0.5In0.5P/DBR were degraded by 0.09% and 6.33%, respectively, with reference to those before annealing.

DOI： 10.1109/LPT.2020.2977376

Web of Science

Scopus

Scalable fabrication of GaN on amorphous substrates via MOCVD on highly oriented silicon seed layers

Hainey, M; Robin, Y; Avit, G; Amano, H; Usami, N

JOURNAL OF CRYSTAL GROWTH 535 巻頁： 125522 2020年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Crystal Growth

The integration of gallium nitride with low-cost, transparent substrates such as glass and crystallographically incompatible substrates such as Si(0 0 1) has been long desired for III-N electronics. Here the authors demonstrate how GaN growth on uniformly 〈1 1 1〉 oriented silicon seed layers fabricated by aluminum-induced crystallization provide a straightforward method for realizing large area GaN growth on these substrate by adopting well-developed GaN on Si(1 1 1) growth processes. Critical factors for promoting high quality GaN growth are identified, and remaining steps necessary for realizing GaN devices are discussed.

DOI： 10.1016/j.jcrysgro.2020.125522

Web of Science

Scopus

Demonstration of Observation of Dislocations in GaN by Novel Birefringence Method

Tanaka, A; Inotsume, S; Harada, S; Hanada, K; Honda, Y; Ujihara, T; Amano, H

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS 257 巻 ( 4 ) 頁： 1900553 2020年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physica Status Solidi (B) Basic Research

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

Web of Science

Scopus

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

Sakai, T; Kushimoto, M; Zhang, ZY; Sugiyama, N; Schowalter, LJ; Honda, Y; Sasaoka, C; Amano, H

APPLIED PHYSICS LETTERS 116 巻 ( 12 ) 頁： 122101 2020年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Applied Physics Letters

We have demonstrated an on-wafer fabrication process for AlGaN-based UV-C laser diodes (LDs) with etched mirrors and have achieved lasing for 100 ns pulsed current injection at room temperature. A combined process of dry and wet etching was employed to achieve smooth and vertical AlGaN (1 1 ¯00) facets. These etched facets were then uniformly coated with a distributed Bragg reflector by atomic layer deposition. A remarkable reduction of the lasing threshold current density to 19.6 kA / cm 2 was obtained owing to the high reflectivity of the etched and coated mirror facets. The entire laser diode fabrication process was carried out on a whole 2-in. wafer. We propose this mirror fabrication process as a viable low-cost AlGaN-based UV-C LD production method that is also compatible with highly integrated optoelectronics based on AlN substrates.

DOI： 10.1063/1.5145017

Web of Science

Scopus

Effects of Ultraviolet Wavelength and Ambient Temperature on Reliability of Silicones in InAlGaN-Based Light-Emitting-Diode Package

Kim Ho-Young, Lee Jong-Woo, Jun Duk-Jin, Song Sung-Joo, Oh Jeong-Tak, Jeong Hwan-Hee, Seong Tae-Yeon, Amano Hiroshi

ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY 9 巻 ( 3 ) 頁： 035005 2020年3月

Visualization of different carrier concentrations in n-type-GaN semiconductors by phase-shifting electron holography with multiple electron biprisms.

Yamamoto K, Nakano K, Tanaka A, Honda Y, Ando Y, Ogura M, Matsumoto M, Anada S, Ishikawa Y, Amano H, Hirayama T

Microscopy (Oxford, England) 69 巻 ( 1 ) 頁： 1-10 2020年3月

Using SiO2-Based Distributed Bragg Reflector to Improve the Performance of AlGaInP-Based Red Micro-Light Emitting Diode

Lee Sang-Youl, Moon Ji Hyung, Moon Yong-Tae, Choi Byoungjun, Oh Jeong-Tak, Jeong Hwan-Hee, Seong Tae-Yeon, Amano Hiroshi

ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY 9 巻 ( 3 ) 頁： 036002 2020年2月

Using SiO<inf>2</inf>-based distributed Bragg reflector to improve the performance of AlGaInP-based red micro-light emitting diode

Lee S.Y., Moon J.H., Moon Y.T., Choi B., Oh J.T., Jeong H.H., Seong T.Y., Amano H.

ECS Journal of Solid State Science and Technology 9 巻 ( 3 ) 2020年2月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：ECS Journal of Solid State Science and Technology

We have investigated how different types of the reflectors affected the optical and electrical performance of AlGaInP-based micro-LEDs. Simulations showed that the AlGaAs-based epitaxial distributed Bragg reflector (DBR) had a stopband at the 610–624 nm region with reflectivity of 90%, the SiO2/TiO2 dielectric DBR gave a stopband at the 580–770 nm range with a maximum reflectivity of 99%, and the ITO/Ag metal reflector exhibited reflectivity of 90% across the 400–800 nm region. All micro-LEDs gave forward voltages of 1.895–1.960 V at 20 μA. The micro-LEDs with the dielectric DBR and metal reflector yielded 31% and 13% higher light output at 20 μA than that with the epitaxial DBR, respectively. All of the micro-LEDs contained a shoulder peak at approximately 615 nm in their electroluminescence spectra. Ray-tracing simulations exhibited that the micro-LEDs with the dielectric DBR and metal reflector produced 26% and 22% higher total light output power than the one with the epitaxial DBR, respectively. It was also shown that for the micro-LEDs with the metal reflector, some of the micro-LEDs were detached from the metal reflectors due to the interfacial voids induced as a result of agglomeration of Ag layer during fabrication process.

DOI： 10.1149/2162-8777/ab74c3/pdf

Scopus

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

Sato, D; Honda, A; Koizumi, A; Nishitani, T; Honda, Y; Amano, H

MICROELECTRONIC ENGINEERING 223 巻頁： 111229 2020年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Microelectronic Engineering

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

Web of Science

Scopus

Effect of unevenly-distributed V pits on the optical and electrical characteristics of green micro-light emitting diode

Lee Da-Hoon, Kang Daesung, Seong Tae-Yeon, Kneissl Michael, Amano Hiroshi

JOURNAL OF PHYSICS D-APPLIED PHYSICS 53 巻 ( 4 ) 頁： 045106 2020年1月

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