H
Hiroaki Okagawa
Researcher at Mitsubishi
Publications - 140
Citations - 2917
Hiroaki Okagawa is an academic researcher from Mitsubishi. The author has contributed to research in topics: Layer (electronics) & Semiconductor. The author has an hindex of 27, co-authored 140 publications receiving 2883 citations. Previous affiliations of Hiroaki Okagawa include Mitsubishi Chemical Corporation.
Papers
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Journal ArticleDOI
High Output Power InGaN Ultraviolet Light-Emitting Diodes Fabricated on Patterned Substrates Using Metalorganic Vapor Phase Epitaxy
Kazuyuki Tadatomo,Hiroaki Okagawa,Youichiro Ohuchi,Takashi Tsunekawa,Yoshiyuki Imada,Munehiro Kato,Tsunemasa Taguchi +6 more
TL;DR: In this paper, a patterned sapphire substrate (PSS) with parallel grooves along the SA direction was fabricated by standard photolithography and subsequent reactive ion etching (RIE).
Journal ArticleDOI
Internal quantum efficiency of highly-efficient InxGa1−xN-based near-ultraviolet light-emitting diodes
Satoshi Watanabe,Norihide Yamada,Masakazu Nagashima,Yusuke Ueki,Chiharu Sasaki,Yoichi Yamada,Tsunemasa Taguchi,Kazuyuki Tadatomo,Hiroaki Okagawa,Hiromitsu Kudo +9 more
TL;DR: In this article, the internal quantum efficiency (IQE) of highly-efficient near-UV light-emitting diodes, which shows an external quantum efficiency of 43% at 406 nm, has been measured by excitation power and temperature-dependent photoluminescence (PL).
Patent
GaN single crystal
TL;DR: A GaN single crystal having a full width at half-maximum of the double-crystal X-ray rocking curve of 5-250 sec and a thickness of not less than 80 μm was presented in this paper.
Patent
Semiconductor base and its manufacturing method, and semiconductor crystal manufacturing method
TL;DR: In this article, a growth plane of substrate 1 is processed to have a concavo-convex surface, and a crystal unit 20 occurs when the crystal growth is started, and then films grown in the lateral direction from the upper part of the convex part 11 as a starting point are connected to cover the concave surface of the substrate 1, leaving a cavity 13 in the concava part, thereby giving a crystal layer 2, whereby the semiconductor base is obtained.
Patent
Nitride semiconductor light emitting element
TL;DR: In this paper, a large chip type GaN-based light emitting element having a light emitting pattern unlike before, for which etching workability is improved, is provided. But, it is not shown how to obtain a light emitter in a mesh shape.