Faculty Profiles - AMANO, Hiroshi

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

Insight into the performance of multi-color InGaN/GaN nanorod light emitting diodes

Robin Y., Bae S. Y., Shubina T. V., Pristovsek M., Evropeitsev E. A., Kirilenko D. A., Davydov V. Yu., Smirnov A. N., Toropov A. A., Jmerik V. N., Kushimoto M., Nitta S., Ivanov S. V., Amano H.

SCIENTIFIC REPORTS Vol. 8 page： 7311 2018.5

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 ) page： 1700645 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

Xu Yang, Shugo Nitta, Markus Pristovsek, Yuhuai Liu, Kentaro Nagamatsu, Maki Kushimoto, Yoshio Honda, Hiroshi Amano

Applied Physics Express Vol. 11 ( 5 ) page： 051002 2018.5

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

Hexagonal boron nitride (h-BN) films directly grown on c-plane sapphire substrates by pulsed-mode metalorganic vapor phase epitaxy exhibit an interlayer for growth temperatures above 1200 °C. Cross-sectional transmission electron microscopy shows that this interlayer is amorphous, while the crystalline h-BN layer above has a distinct orientational relationship with the sapphire substrate. Electron energy loss spectroscopy shows the energy-loss peaks of B and N in both the amorphous interlayer and the overlying crystalline h-BN layer, while Al and O signals are also seen in the amorphous interlayer. Thus, the interlayer forms during h-BN growth through the decomposition of the sapphire at elevated temperatures.

DOI： 10.7567/APEX.11.051002

Transferrable monolithic multicomponent system for near-ultraviolet optoelectronics

Chuan Qin, Xumin Gao, Jialei Yuan, Zheng Shi, Yuan Jiang, Yuhuai Liu, Yongjin Wang, Hiroshi Amano

Applied Physics Express Vol. 11 ( 5 ) page： 051201 2018.5

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

A monolithic near-ultraviolet multicomponent system is implemented on a 0.8-mm-diameter suspended membrane by integrating a transmitter, waveguide, and receiver into a single chip. Two identical InGaN/Al0.10Ga0.90N multiple-quantum well (MQW) diodes are fabricated using the same process flow, which separately function as a transmitter and receiver. There is a spectral overlap between the emission and detection spectra of the MQW diodes. Therefore, the receiver can respond to changes in the emission of the transmitter. The multicomponent system is mechanically transferred from silicon, and the wire-bonded transmitter on glass experimentally demonstrates spatial light transmission at 200 Mbps using non-return-to-zero on–off keying modulation.

DOI： 10.7567/APEX.11.051201

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 ) page： 182106 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