研究者詳細 - 天野　浩

論文 - 天野　浩

分割表示 827 件中 201 - 220 件目／全件表示 >>

Hole injection mechanism in the quantum wells of blue light emitting diode with V pits for micro-display application

Kang, D; Oh, JT; Song, JO; Seong, TY; Kneissl, M; Amano, H

APPLIED PHYSICS EXPRESS 12 巻 ( 10 ) 頁： 102016 2019年10月

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

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

AIP ADVANCES 9 巻 ( 9 ) 頁： 095002 2019年9月

Stability and degradation of AlGaN-based UV-B LEDs: Role of doping and semiconductor defects

Piva F., De Santi C., Deki M., Kushimoto M., Amano H., Tomozawa H., Shibata N., Meneghesso G., Zanoni E., Meneghini M.

Microelectronics Reliability 100-101 巻頁： 113418 2019年9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：Microelectronics Reliability

Within this paper, we present an extensive analysis of the degradation of UV-B light-emitting diodes (LEDs) submitted to constant current stress. The study is based on combined electrical, optical and spectral characterization, and capacitance deep-level transient spectroscopy (C-DLTS). The results of this analysis demonstrate that the decrease in the optical power during the stress is stronger at low measuring current levels, indicating that the degradation is related to the increase in Shockley-Read-Hall (SRH) recombination. The electrical characterization shows a decrease in the driving voltage, probably due to an increased activation of the Mg dopant, and an increase in the sub-threshold forward current, that suggest a generation of mid-gap states during the stress. C-DLTS measurements were carried out to study the variation in defects concentration after stress; the most relevant traps were ascribed to the presence of Mg doping and/or to intrinsic defects related to the GaN growth.

DOI： 10.1016/j.microrel.2019.113418

Web of Science

Scopus

Via-Hole-Type Flip-Chip Packaging to Improve the Thermal Characteristics and Reliability of Blue Light Emitting Diodes

Kim, HY; Lim, CM; Kim, KS; Oh, JT; Jeong, HH; Song, JO; Seong, TY; Amano, H

ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY 8 巻 ( 9 ) 頁： Q165 - Q170 2019年8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 via-holes in the lead-frame on the reliability of blue flip-chip light-emitting diodes (FCLEDs). For bonding, conventional Sn-Ag(3.0%)-Cu(0.5%) solder (SAC) and Ag sintered paste were adopted. Lateral LED, conventional FCLED (c-FCLED), and via-hole FCLED gave efficacies of 218.5, 221.6 and 225 lm/W at 30 mA. The lateral LED sample (bonding material: silicone), c-FCLED sample (SAC), via-hole-type sample (Ag sinter), and via-hole-type sample (SAC) exhibited total thermal resistance of 15.24, 10.19, 8.95, and 11.79 K/W, respectively. The humidity/temperature/H2S gas reliability examinations showed that unlike the via-hole-type samples, the lumen of the c-FCLED was fallen by 15.0% after exposure for 500 h. Furthermore, the c-FCLED exhibited a 19.6% higher forward voltage than the via-hole FCLED after 1,000 thermal-cycles. SEM results showed that unlike the via-hole type FCLED, the c-FCLED underwent cracking after thermal cycle of 1000 times.

DOI： 10.1149/2.0171909jss

Web of Science

Scopus

Combined effects of V pits and chip size on the electrical and optical properties of green InGaN-based light-emitting diodes

Kim Dae-Hyun, Park Young Soo, Kang Daesung, Kim Kyoung-Kook, Seong Tae-Yeon, Amano Hiroshi

JOURNAL OF ALLOYS AND COMPOUNDS 796 巻頁： 146-152 2019年8月

Indium Incorporation into InGaN Quantum Wells Grown on GaN Narrow Stripes

Sarzynski Marcin, Grzanka Ewa, Grzanka Szymon, Targowski Grzegorz, Czernecki Robert, Reszka Anna, Holy Vaclav, Nitta Shugo, Liu Zhibin, Amano Hiroshi, Leszczynski Mike

MATERIALS 12 巻 ( 16 ) 頁： 2583 2019年8月

Influence of Temperature-Dependent Substrate Decomposition on Graphene for Separable GaN Growth

Park Jeong-Hwan, Lee Jun-Yeob, Park Mun-Do, Min Jung-Hong, Lee Je-Sung, Yang Xu, Kang Seokjin, Kim Sang-Jo, Jeong Woo-Lim, Amano Hiroshi, Lee Dong-Seon

ADVANCED MATERIALS INTERFACES 6 巻頁： 1900821 2019年7月

Fabrication of a GaInN/GaInP/GaInAs/Ge four-junction solar cell using the wafer bonding technology

Takahashi, K; Shinoda, R; Mitsufuji, S; Iwaya, M; Kamiyama, S; Takeuchi, T; Hattori, T; Akasaki, I; Amano, H

JAPANESE JOURNAL OF APPLIED PHYSICS 58 巻 ( 7 ) 頁： 072003 2019年7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：Japanese Journal of Applied Physics

We fabricated a GaInN/GaInP/GaInAs/Ge four-junction solar cell by wafer bonding a GaInN solar cell and a GaInP/GaInAs/Ge three-junction solar cell. We performed our wafer bonding at high pressure (500 N) and temperature (450 °C) by using p-type GaN and n-type GaAs. The open-circuit voltage (V OC), J SC, and fill factor of our four-junction solar cell under the condition of AM 1.5 G, i.e., 1 sun are 2.85 V, 0.219 mA cm-2, and 0.74, respectively. The improved V OC of our four-junction solar cells was confirmed by a series connection. The J SC is almost comparable to the theoretical value (itself based on the assumption of an ideal series junction), but the V OC is approximately 1 V less than that predicted by theory. Our research will improve the solar cell efficiency and help meet future energy needs.

DOI： 10.7567/1347-4065/ab26ad

Web of Science

Scopus

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

Matsumoto, K; Ono, T; Honda, Y; Torigoe, K; Kushimoto, M; Amano, H

JAPANESE JOURNAL OF APPLIED PHYSICS 58 巻 ( 7 ) 頁： 075502 2019年7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：Japanese Journal of Applied Physics

This study investigated the change in carrier concentration near the surface of a silicon substrate during gallium nitride (GaN) growth with an aluminum nitride (AlN) buffer layer. It was observed that aluminum, gallium, and carbon diffused into the silicon substrate during the growth process and that the carrier concentration increased with increasing concentration of aluminum and gallium impurities. The gallium that diffused into the silicon substrate was identified as having originated from the gallium that decomposed on the reactor wall during the growth process and the gallium introduced onto the silicon substrate during GaN growth. In contrast, the amount of aluminum that diffused into the substrate was influenced by the duration of the trimethylaluminum (TMAl) flow: A long duration of the TMAl flow step before AlN growth led to a high aluminum concentration near the substrate surface.

DOI： 10.7567/1347-4065/ab2657

Web of Science

Scopus

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

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

JOURNAL OF CRYSTAL GROWTH 516 巻頁： 63-66 2019年6月

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

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

APPLIED PHYSICS LETTERS 114 巻 ( 23 ) 頁： 232105 2019年6月

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

Liu, Q; Fujimoto, N; Nitta, S; Honda, Y; Amano, H

JAPANESE JOURNAL OF APPLIED PHYSICS 58 巻 ( SC ) 頁： SC1055 2019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：Japanese Journal of Applied Physics

In order to make low cost bulk GaN single crystal with a high growth rate, we have built a vertical HVPE reactor with a showerhead configuration. The flow from the showerhead of the reactor is independently controlled by inner/outer two sets of gas supply lines. This special showerhead design makes the flow model different from the conventional showerhead reactors. We have employed a finite element-based simulator to study the fluid dynamic and crystal growth of this inner/outer flow independently controlled showerhead. Two simulation experiments were performed. One experiment has demonstrated that both growth rate and Ga yield can be improved without compromising the uniformity by controlling the different input parameters of inner and outer flow on the showerhead, as compared with the conventional showerhead. The other experiment has demonstrated that the showerhead can be further optimized by changing the inner/outer area ratio and input parameters.

DOI： 10.7567/1347-4065/ab124e

Web of Science

Scopus

Monolithic integration of tricolor micro-LEDs and color mixing investigation by analog and digital dimming

Robin, Y; Hemeret, F; D'Inca, G; Pristovsek, M; Trassoudaine, A; Amano, H

JAPANESE JOURNAL OF APPLIED PHYSICS 58 巻 ( SC ) 頁： SCCC06 2019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：Japanese Journal of Applied Physics

We report on the growth, processing and optical characterization of monolithically integrated tricolor micro-LEDs. The 100 × 100 μm2 active area of the devices is composed of independent subpixels emitting in the blue, green and yellow-orange range with color saturation of over 90% for all bands. The gamut of the device is recorded by both digital and analog dimming, i.e. by pulse width modulation or by varying the current density. Results indicate color mixing performed by both methods leads to a rotated or distorted gamut significantly different from the one predicted by the CIE color model. We explain our findings in terms of quantum-confined Stark effect screening and efficiency droop at high current density, which modify the expected hue and brightness of mixed colors.

DOI： 10.7567/1347-4065/ab06ae

Web of Science

Scopus

Effect of photoelectrochemical etching and post-metallization annealing on gate controllability of AlGaN/GaN high electron mobility transistors

Uemura, K; Deki, M; Honda, Y; Amano, H; Sato, T

JAPANESE JOURNAL OF APPLIED PHYSICS 58 巻 ( SC ) 頁： SCCD20 2019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：Japanese Journal of Applied Physics

Recessed-gate AlGaN/GaN metal-insulator-semiconductor (MIS) high electron mobility transistors (HEMTs) were fabricated by utilizing a photoelectrochemical (PEC) etching and a post-metallization annealing (PMA) process. In order to demonstrate the device performance and reliability, both electrical and optical electroluminescence (EL) properties were evaluated. The capacitance-voltage (C-V) characteristic showed that the PEC etching and subsequent PMA process enhanced the gate control of two-dimensional electron gas density. The PEC-etched-gate AlGaN/GaN MIS-HEMT showed the smallest sub-threshold slope of all the samples including planar-gate and inductively coupled plasma-etched-gate devices. Furthermore, the PEC-etched devices showed an extremely low 10-11 A mm-1 gate leakage current with no spot-like EL. These results indicated that the PEC etching and subsequent PMA process improved the electrical properties of the Al2O3/AlGaN interface, resulting in enhanced device performance of the AlGaN/GaN MIS-HEMTs.

DOI： 10.7567/1347-4065/ab06b9

Web of Science

Scopus

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

Fukushima, H; Usami, S; Ogura, M; Ando, Y; Tanaka, A; Deki, M; Kushimoto, M; Nitta, S; Honda, Y; Amano, H

JAPANESE JOURNAL OF APPLIED PHYSICS 58 巻 ( SC ) 頁： SCCD25 2019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：Japanese Journal of Applied Physics

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.

DOI： 10.7567/1347-4065/ab106c

Web of Science

Scopus

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

Usami, S; Tanaka, A; Fukushima, H; Ando, Y; Deki, M; Nitta, S; Honda, Y; Amano, H

JAPANESE JOURNAL OF APPLIED PHYSICS 58 巻 ( SC ) 頁： SCCB24 2019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：Japanese Journal of Applied Physics

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.

DOI： 10.7567/1347-4065/ab1250

Web of Science

Scopus

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

Nan, H; Dinh, DV; Pristovsek, M; Honda, Y; Amano, H

JAPANESE JOURNAL OF APPLIED PHYSICS 58 巻 ( SC ) 頁： SC1044 2019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：Japanese Journal of Applied Physics

We have studied the impact on the surface orientation of different sputtered Al layers followed by AlN layers sputtered on m-plane sapphire. These initial layers were then overgrown by AlN and followed by GaN using metal-organic vapor phase epitaxy (MOVPE). By increasing sputtering time of the initial Al layer from 0 s to 15 s, we obtained single phase (10-10), (10-13) and (10-14) GaN/AlN layers. The thickness of the initial Al layer was estimated by optical transmission measurements to be about 0.5-1 nm for the (10-13) orientation, and >1 nm for the (10-14) orientation. After MOVPE growth, no trace of metallic Al was found by transmission electron microscopy, indicating that this layer was fully converted to AlN.

DOI： 10.7567/1347-4065/ab1252

Web of Science

Scopus

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

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

APPLIED PHYSICS EXPRESS 12 巻 ( 6 ) 頁： 064009 2019年6月

Narrow Excitonic Lines in Core-Shell Nanorods With InGaN/GaN Quantum Wells Intersected by Basal Stacking Faults

Evropeitsev Evgeniy A., Robin Yoann, Shubina Tatiana V., Bae Si-Young, Nitta Shugo, Kirilenko Demid A., Davydov Valery Y., Smirnov Alexandr N., Toropov Alexey A., Kushimoto Maki, Ivanov Sergey V., Amano Hiroshi

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS 256 巻 ( 6 ) 頁： 1800648 2019年6月

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

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

JOURNAL OF CRYSTAL GROWTH 514 巻頁： 13-13 2019年5月

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