| Project/Area Number |
13450004
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | University of Tsukuba |
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Principal Investigator |
TAKITA Koki University of Tsukuba, Institute of Materials Science, Professor, 物質工学系, 教授 (00011213)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAMASU Tadashi National Institute of Materials Science, Chief Researcher, ナノテクノロジー研究所, 主任研究官 (60212015)
OZAKI Nobuhiko University of Tsukuba, Institute of Materials Science, Research Associate, 物質工学系, 助手 (30344873)
黒田 眞司 筑波大学, 物質工学系, 講師 (40221949)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥13,100,000 (Direct Cost: ¥13,100,000)
Fiscal Year 2003: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2002: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2001: ¥6,700,000 (Direct Cost: ¥6,700,000)
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| Keywords | self-organized dots / lattice mismatch / diluted magnetic semiconductors / photoluminescence / zero-dimensional exciton / 希薄性半導体 / 2次元電子系 / 量子ドット / スピントロニクス / 磁気発光特性 / 磁気輸送特性 / マイグレーション |
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| Research Abstract |
We have fabricated self-organized dots of CdTe and Cd1-xMnxTe on ZnTe(001) surface by molecular beam epitaxy (MBE). In the present research project, we have performed the following two topics. (1) change the confinement energy of electrons and holes due to the barrier layer by growing the dots on the mixed crystal (band-gap engineering) (2) make the structure in which the dot layer and the barrier layer are grown repeatedly (dot superlattice), as the details are described in the following.
(1) Band-gap engineering by changing the barrier layer
We have grown self-organized dots of CdTe on the mixed crystals of (Zn, Mg)Te, in place of ZnTe. In the photoluminescence measurement, it was found that the temperature dependence of the luminescence intensity was improved significantly, with the suppression of the thermal quenching of the luminescence, compared to the dots on ZnTe. This is considered to be caused by the enhancement of the confinement of electron-hole pairs due to the increase of t
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he band-gap energy of the barrier layer. In addition, we grew (Cd, Mn)Te dots on (An, Mg)Te layer in the similar method. In the magneto-PL measurement, we observed the red-shift of the exicitonic emission energy due to the gigantic Zeeman splitting, the amount of this red-shift was found to be consistent with the calculation.
(2) Dot superlattice
We have fabricated the superlattice structure in which the Cd(Mn)Te dot layer and ZnTe barrier layer were stacked with several tens of cycles. In the PL measurement, we observed two emission lines, differently from the sample with the dot single layer. It is considered that the higher-energy line originated from the isolated level of the individual dots and the lower-energy line originated from the correlated level between the dots in the neighboring dot layers. This assignment was confirmed from the results of the PL measurement on a series of sample wiath different thickness of the barrier layers, in which the emission energy of the lower-energy line was shifted systematically with the barrier thickness. Less
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