T
Takafumi Yao
Researcher at Tohoku University
Publications - 591
Citations - 14672
Takafumi Yao is an academic researcher from Tohoku University. The author has contributed to research in topics: Molecular beam epitaxy & Photoluminescence. The author has an hindex of 49, co-authored 591 publications receiving 14287 citations. Previous affiliations of Takafumi Yao include National Institute of Advanced Industrial Science and Technology.
Papers
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Proceedings ArticleDOI
Making ferromagnetic semiconductors out of III-V nitride semiconductors
TL;DR: In this article, the gap state is attributed to Ga 4s originated state caused by strong hybridization between Cr 3d and band electrons of host GaN. But, it is found that the doped Cr contributes to form gap states, which pin the Fermi level.
Journal ArticleDOI
Nanometer-scale characterization of lateral p-n + junction by scanning capacitance microscope
Hideto Tomiye,Takafumi Yao +1 more
TL;DR: In this paper, the spatial variation of the local capacitance of a lateral p-n+ junction is measured at various sample biases by a home-made Scanning Capacitance Microscope (SCaM)/Atomic Force Microscope, which facilitates direct measurements of capacitance itself.
Journal ArticleDOI
Localization and thermal escape of excitons in ultrathin ZnSe/ZnS single quantum wells linked to interfacial ZnSe quantum slabs
P. Tomasini,K. Arai,Fang Lu,Ziqiang Zhu,Takashi Sekiguchi,Takafumi Yao,Mengyan Shen,Takenari Goto +7 more
TL;DR: In this paper, the optical properties of pseudomorphic ZnSe/ZnS single quantum well structures have been investigated by conventional optical methods, and power dependence and temperature dependence measurements show that structural disorder plays an important role in ultrathin single quantum wells.
Journal ArticleDOI
Adsorption processes of Se on the GaAs(111)A–(2x2) surface
TL;DR: In this paper, a structure model was proposed for the GaAs(111)A surface, which consists of two Se trimers located at a hollow site of the surface and three Ga vacancies per unit cell.
Journal ArticleDOI
Local stress distribution in GaN vertical light-emitting diodes fabricated using CLO and LLO methods
TL;DR: In this paper, the local stress distribution in a GaN-based vertical light-emitting diode (V-LED) fabricated using two types of separation methods: a chemical liftoff (CLO) procedure and a laser lift-off (LLO) technique.