T
Takeyoshi Onuma
Researcher at Kogakuin University
Publications - 65
Citations - 1835
Takeyoshi Onuma is an academic researcher from Kogakuin University. The author has contributed to research in topics: Photoluminescence & Cathodoluminescence. The author has an hindex of 17, co-authored 65 publications receiving 1458 citations. Previous affiliations of Takeyoshi Onuma include Tohoku University & University of Tsukuba.
Papers
More filters
Journal ArticleDOI
Blue Light-Emitting Diode Based on ZnO
Atsushi Tsukazaki,Masashi Kubota,Akira Ohtomo,Takeyoshi Onuma,Keita Ohtani,Hideo Ohno,Shigefusa F. Chichibu,Masashi Kawasaki +7 more
TL;DR: In this article, a near-band-edge bluish electroluminescence (EL) band centered at around 440 nm was observed from ZnO p-i-n homojunction diodes through a semi-transparent electrode deposited on the p-type top layer.
Journal ArticleDOI
Valence band ordering in β-Ga2O3 studied by polarized transmittance and reflectance spectroscopy
Takeyoshi Onuma,Takeyoshi Onuma,Shingo Saito,Kohei Sasaki,Tatekazu Masui,Tomohiro Yamaguchi,Tohru Honda,Masataka Higashiwaki +7 more
TL;DR: In this paper, the polarized transmittance and reflectance spectra of β-Ga2O3 crystals are investigated, and the data are interpreted in terms of the monoclinic crystal band structure.
Journal ArticleDOI
Correlation between blue luminescence intensity and resistivity in β-Ga2O3 single crystals
Takeyoshi Onuma,Shuhei Fujioka,Tomohiro Yamaguchi,Masataka Higashiwaki,Kohei Sasaki,Tatekazu Masui,Tohru Honda +6 more
TL;DR: In this paper, temperature-dependent cathodoluminescence spectra were measured from (001) unintentionally doped, (100) Si-doped, and (010) Mgdoped β-Ga2O3 substrates prepared by either the floating zone growth or edge-defined film-fed growth methods.
Journal ArticleDOI
Polarized Raman spectra in β-Ga2O3 single crystals
Takeyoshi Onuma,Takeyoshi Onuma,Shuhei Fujioka,Tomohiro Yamaguchi,Y. Itoh,Masataka Higashiwaki,Kohei Sasaki,Tatekazu Masui,Tohru Honda +8 more
TL;DR: In this paper, a complete set of polarized Raman spectra of β-Ga 2 O 3 was measured from (010) Mg-doped, (100) Si-doping, and (001) unintentionally-labeled β-ga 2 O3 substrates prepared by either the floating zone growth or edge-defined film-fed growth methods.
Journal ArticleDOI
Modeling and interpretation of UV and blue luminescence intensity in β-Ga2O3 by silicon and nitrogen doping
Takeyoshi Onuma,Takeyoshi Onuma,Yoshiaki Nakata,Kohei Sasaki,Takekazu Masui,Tomohiro Yamaguchi,Tohru Honda,Akito Kuramata,S. Yamakoshi,Masataka Higashiwaki +9 more
TL;DR: In this paper, temperature-dependent cathodoluminescence spectra of Si-doped β-Ga2O3 single crystals and Ndoped epitaxial films were comprehensively shown to investigate their electronic structure and defect states.