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Your search keyword '"Amano, Hiroshi"' showing total 42 results
Start Over Author "Amano, Hiroshi" Journal applied physics letters
42 results on '"Amano, Hiroshi"'

1. Non-polar true-lateral GaN power diodes on foreign substrates

Author

Wang, Jia, Yu, Guo, Zong, Hua, Liao, Yaqiang, Lu, Weifang, Cai, Wentao, Hu, Xiaodong, Xie, Ya-Hong, and Amano, Hiroshi

Subjects
Engineering, Materials Engineering, Physical Sciences, Technology, Applied Physics, Physical sciences
Abstract

We have demonstrated non-polar GaN power diodes (Schottky barrier diode and p–n junction diode) on foreign substrates featuring the true-lateral p–n and metal–semiconductor junctions. The diodes were fabricated on GaN islands laterally overgrown on the mask-patterned sapphire and Si substrates by metalorganic vapor phase epitaxy. The anode and cathode were formed on the opposed a-plane sidewalls of the island, making the device architecture essentially like the 90° rotation of the desired true-vertical power diodes. The ideality factor of the Schottky barrier diode remained 1.0 (from 1.00 to 1.05) over 7 decades in current. Specifically, a high critical electric field of 3.3 MV/cm was demonstrated on the p–n junction diode with avalanche capability. These performances reveal a strong potential of non-polar GaN with the true-lateral junctions for high power applications.

Published
2021

3. Discovering the incorporation limits for wurtzite AlPyN1−y grown on GaN by metalorganic vapor phase epitaxy.

Author

Yang, Xu, Furusawa, Yuta, Kano, Emi, Ikarashi, Nobuyuki, Amano, Hiroshi, and Pristovsek, Markus

Subjects
ANTISITE defects, TWO-dimensional electron gas, LATTICE constants, ELECTRON mobility, CARRIER gas
Abstract

We report on the growth of AlPN on GaN/sapphire templates by metalorganic vapor phase epitaxy using tertiarybutylphosphine (tBP) and NH3 as group-V precursors. P is easy to incorporate into the group-III lattice site, forming PAl anti-site defects and shrinking lattice constants that are even beyond AlN since Al is larger than P. We found that higher temperatures favor P incorporation on the N-sublattice, forming AlPyN1−y, while growth temperatures below 1000 °C result in dominant P incorporation on the Al-sublattice, forming PAl anisites. Similarly, larger NH3 flows stabilize GaN, leading to flat interfaces, but favor the formation of PAl. Furthermore, the P incorporation into AlPyN1−y is non-linear. At very low tBP flows, it initially increases to reach a maximum. Further increasing the tBP flow increases mostly the incorporation of P on the Al-sublattice, and the c-lattice constant decreases again. This leaves a small window of low V/III ratios below 5 and low P/N ratios of 1% or smaller, leading up to ∼4% P incorporation at typical growth temperatures of GaN. However, at such low V/III ratios, GaN is not stable even with N2 carrier gas and requires optimized switching sequences to minimize its decomposition and preserve flat interfaces. Eventually, a 10 nm coherent layer of AlP0.01N0.99 could be reproducibly grown on top of GaN channels with a smooth surface, an abrupt AlPN/GaN interface, and a two-dimensional electron gas with an electron mobility of ∼675 cm2/V s and a sheet carrier density of 1.5 × 1013 cm−2 at room temperature. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Impact of unintentionally formed compositionally graded layer on carrier injection efficiency in AlGaN-based deep-ultraviolet laser diodes.

Author

Zhang, Ziyi, Yoshikawa, Akira, Kushimoto, Maki, Aoto, Koji, Sasaoka, Chiaki, and Amano, Hiroshi

Subjects
DEBYE temperatures, SEMICONDUCTOR lasers, ACTIVE medium
Abstract

Increasing the injection efficiency, a critical factor constraining the reduction in threshold current in AlGaN-based deep-ultraviolet laser diodes, represents one of the paramount remaining technical challenges. In this study, the impact of compositionally graded layers that were unintentionally formed at the interface between the p-cladding and the core layer on carrier injection efficiency was analyzed. Experimental evaluations using laser diodes have shown that the elimination of an unintentionally formed layer increases the injection efficiency above the threshold current, from the conventional 3% to 13%. It has been postulated that the electron overflow toward the p-side exerts a substantial deleterious effect on the injection efficiency. An improvement in this aspect is achieved by increasing the electron-blocking capability due to the improved interface abruptness between the p-cladding layer and the core layer. The lasing threshold was strongly reduced, and characteristic temperature increased from 76 to 107 K for the improved devices. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Electron lifetime and diffusion coefficient in dopant-free p-type distributed polarization doped AlGaN.

Author

Kumabe, Takeru, Kawasaki, Seiya, Watanabe, Hirotaka, Honda, Yoshio, and Amano, Hiroshi

Subjects
DIFFUSION coefficients, ELECTRON mobility, ELECTRON diffusion, DIODES, GALLIUM nitride, ATOMS
Abstract

Minority carrier properties in dopant-free p-type distributed polarization doped (DPD) AlGaN layers were investigated on the basis of the forward-biased current density–voltage (J–V) characteristics of p–n+ diodes. The fabricated p-DPD AlGaN/n+–AlGaN:Si diodes exhibited ideal electrical characteristics despite the absence of acceptor atoms in the p-type layer. The extracted Shockley–Read–Hall lifetime exceeded 300 ps, which was longer than that reported for p-GaN:Mg on GaN substrates with a similar acceptor concentration (20–50 ps). Moreover, the electron diffusion coefficient was about 20 cm2 s−1 at any temperature, which was convincing in terms of the electron mobility in DPD layers. The results suggest that p-DPD AlGaN has more desirable minority carrier properties than conventional p-GaN:Mg, particularly for bipolar device applications. [ABSTRACT FROM AUTHOR]

Published
2023
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14. Monolithic GaN optoelectronic system on a Si substrate

Author

Zhang, Hao, primary, Yan, Jiabin, additional, Ye, Ziqi, additional, Shi, Fan, additional, Piao, Jinlong, additional, Wang, Wei, additional, Gao, Xumin, additional, Zhu, Hongbo, additional, Wang, Yongjin, additional, Liu, Yuhuai, additional, and Amano, Hiroshi, additional

Published
2022
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25. Vertical GaN p+-n junction diode with ideal avalanche capability grown by halide vapor phase epitaxy.

Author

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

Subjects
GALLIUM nitride, AVALANCHE diodes, BREAKDOWN voltage, EPITAXY, GASES, AVALANCHES
Abstract

A vertical GaN p+-n junction diode with an ideal breakdown voltage was grown by halide vapor phase epitaxy (HVPE). A steep p+-n interface was observed even with the use of the HVPE method. No Si-accumulating layer was formed at the p+-n interface because of the continuous HVPE growth from the n-type drift layer to the p-type layer. This method provides improved electrical properties compared with the regrowth of p-type GaN layers. The minimum ideality factor of approximately 1.6 was obtained. The breakdown voltage increased from 874 to 974 V with the increase in the temperature from 25 to 200 °C, which suggests that avalanche multiplication causes the breakdown. The temperature-dependent breakdown voltage was in good agreement with the breakdown voltage calculated using the ideal critical electric field. These results indicate that HVPE is promising for the fabrication of vertical GaN power devices. [ABSTRACT FROM AUTHOR]

Published
2021
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29. Initial leakage current paths in the vertical-type GaN-on-GaN Schottky barrier diodes

Author

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

Published
2017
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40. The electrical properties of Mg-doped a-plane Ga1-xInxN (0<x<0.30) films on undoped GaN grown by sidewall-epitaxial-lateral overgrowth on +0.5°-off r-plane sapphire substrates by metalorganic vapor phase epitaxy were

Author

Iida, Daisuke, Iwaya, Motoaki, Kamiyama, Satoshi, Amano, Hiroshi, and Akasaki, Isamu

Subjects
SEMICONDUCTOR doping, SAPPHIRES, SUBSTRATES (Materials science), EPITAXY, PHASE transitions, TEMPERATURE effect, CONCENTRATION functions
Abstract

The electrical properties of Mg-doped a-plane Ga1-xInxN (00.83In0.17N was as small as 48 meV. Therefore, highly Mg-doped a-plane GaInN with a high hole concentration can be realized. A maximum hole concentration of as high as 1.7×1019 cm-3 in Ga0.71In0.29N was reproducibly achieved at room temperature. [ABSTRACT FROM AUTHOR]

Published
2008
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41. Observation of photoluminescence from Al[sub 1-x]In[sub x]N heteroepitaxial films grown by metalorganic vapor phase epitaxy.

Author

Yamaguchi, Shigeo, Kariya, Michihiko, Nitta, Shugo, Takeuchi, Tetsuya, Wetzel, Christian, Amano, Hiroshi, and Akasaki, Isamu

Subjects
PHOTOLUMINESCENCE, QUANTUM wells, X-ray diffraction, SCIENCE
Abstract

We have observed photoluminescence of Al[sub 1-x]In[sub x]N films. The films were grown on GaN by atmospheric pressure metalorganic vapor phase epitaxy. GaN was grown on a c-plane sapphire substrate with a low-temperature deposited AlN buffer layer. Photoluminescence, absorption, and x-ray diffraction measurements have shown that each spectral peak shifts with alloy composition x and that Al[sub 1-x]In[sub x]N heteroepitaxial films are not macroscopically in phase separation and are constituted in the wurzite structure. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
1998
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42. Anomalous features in the optical properties of Al[sub 1-x]In[sub x]N on GaN grown by metal organic vapor phase epitaxy.

Author

Yamaguchi, Shigeo, Kariya, Michihiko, Nitta, Shugo, Takeuchi, Tetsuya, Wetzel, Christian, Amano, Hiroshi, and Akasaki, Isamu

Subjects
THIN films, OPTICAL properties, GALLIUM nitride, EPITAXY
Abstract

We have studied the optical properties of Al[sub 1-x]In[sub x]N thin films grown on GaN by metal organic vapor phase epitaxy. X-ray diffraction analysis of ω and ω-2θ scans showed that both the compositional fluctuation and the degree of crystalline mosaicity increase with increasing x. While the energy positions of both the absorption edge and photoluminescence peak shift to a lower-energy region with increasing x, the linewidth of the photoluminescence spectra and the value of the absorption edge tail decrease. The Stokes shift also decreases with increasing x, following which both energy positions become 1.66 eV, which is smaller than the band gap of InN (1.9 eV). These anomalous features of the optical properties of Al[sub 1-x]In[sub x]N might be affected by the absorption in the infrared region caused by the high electron concentration. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2000
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