M
Meoung Whan Cho
Researcher at Tohoku University
Publications - 29
Citations - 638
Meoung Whan Cho is an academic researcher from Tohoku University. The author has contributed to research in topics: Molecular beam epitaxy & Epitaxy. The author has an hindex of 10, co-authored 29 publications receiving 612 citations. Previous affiliations of Meoung Whan Cho include Stanley Electric.
Papers
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Journal ArticleDOI
Origin of forward leakage current in GaN-based light-emitting devices
S. W. Lee,D. C. Oh,Hiroki Goto,J. S. Ha,H. J. Lee,Takashi Hanada,Meoung Whan Cho,Takafumi Yao,Soon-Ku Hong,H. Y. Lee,S. R. Cho,J. W. Choi,J. H. Choi,J. H. Jang,J. E. Shin,J. S. Lee +15 more
TL;DR: In this article, two different GaN-based light-emitting diodes (LEDs) were fabricated on two GaN templates with the same LED structure, and the correlation between currentvoltage characteristics and etch pit density of LEDs was studied.
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Structural variation of cubic and hexagonal MgxZn1−xO layers grown on MgO(111)∕c-sapphire
Z. Vashaei,Tsutomu Minegishi,H. Suzuki,Takashi Hanada,Meoung Whan Cho,Takafumi Yao,Agus Setiawan +6 more
TL;DR: In this paper, the structure study of MgxZn1−xO films with x = 0.28 and 0.41 MgZnO layers with different crystal structures of cubic and wurtzite was reported.
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Characteristics of dislocations in ZnO layers grown by plasma-assisted molecular beam epitaxy under different Zn∕O flux ratios
Agus Setiawan,Z. Vashaei,Meoung Whan Cho,Takafumi Yao,Hiroyuki Kato,Michihiro Sano,Kazuhiro Miyamoto,I. Yonenaga,Hang-Ju Ko +8 more
TL;DR: In this paper, the authors investigated the characteristic of threading dislocations in the ZnO layers grown on c sapphire by the plasma-assisted molecular beam epitaxy under the different Zn∕O flux ratios.
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Electron-trap centers in ZnO layers grown by molecular-beam epitaxy
Abstract: We have investigated electron-trap centers in ZnO layers grown under different Zn∕O flux ratios by molecular-beam epitaxy. Frequency-dependent capacitance measurements show that ZnO layers grown under Zn-rich and stoichiometric flux conditions suffer from larger dispersion than a ZnO layer grown under an O-rich flux condition. Temperature-dependent capacitance measurements reveal that all the ZnO layers have shallow electron-trap centers ET1 and deep electron-trap centers ET2, while the Zn-rich ZnO layer has another shallow electron-trap center ET3 besides ET1 and ET2: the thermal activation energies of ET1, ET2, and ET3 are estimated to be 0.033–0.046, 0.12–0.15, and 0.065 eV, respectively. Moreover, it is exhibited that the trap density of ET2 is larger than those of ET1 or ET3 in all the cases and increases as the Zn∕O flux ratio increases. Consequently, it is suggested that the large dispersion effect observed in the Zn-rich and stoichiometric ZnO layers is ascribed to the large density of deep electr...
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Issues in ZnO homoepitaxy
TL;DR: In this paper, the surface morphology and crystallinity were evaluated by means of high resolution X-ray diffraction (XRD), photoluminescence (PL) and atomic force microscopy (AFM).