| Co-Investigator(Kenkyū-buntansha) |
BABA Motoyoshi Institute for Silid Sate Physics, University of Tokyo, Research Associate, 物性研究所, 教務職員 (60159077)
YOSHITA Masahiro Institute for Silid Sate Physics, University of Tokyo, Research Associate, 物性研究所, 助手 (30292759)
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| Research Abstract |
We have investigated the one-dimensional (1D) exciton effect from low up to room temperature and preventing factors in the physics and material point of view in order to achieve 1D GaAs quantum wire (QWR) photo-emission devices. For this purpose, we have developed microscopic photoluminescence (PL) imaging and spectroscopy system with high resolution and efficiency which is stable against temperature variation.
Introduction of In GaAs material to T-shaped quantum wires was tried to stabilize the ID excitons. It turned out that the lateral confinement energy of QWR was increased to 35meV, which is about two times larger than 18meV observed for the corresponding GaAs T-QWRs. The temperature dependence of PL have shown that excitons are stable up to 150K in the sample. Introduction of AIAs barrier will further stabilize the ID excitons to make PL at room temperature.
The major difficulty of T-QWRs lies in the MBE growth on the cleaved (110) crystal surface. We have investigated (110) MBE-grown surface of GaAs of atomic force microscopy and our microscopic PL imaging and spectroscopy system. The micrometer-scale large terrace formation inherent to (110) surface and the resulted modulated electronic states were observed, which contributes to the exciton diffusion and thermal activation processes at various temperatures.
Ridge QWR lasers with low controllability but with inherently strong confinement have been also designed, fabricated, and characterized. They did lase at room temperature, on which we studied microscopic origin, temperature dependence, and uniformity.
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