2002 Fiscal Year Final Research Report Summary
Physics and controlled properties of micro-and nano-scale granular semiconductor structures
| Project/Area Number |
12450120
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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 |
Electronic materials/Electric materials
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SAKAKI Hiroyuki Institute of Industrial Science, Professor, 生産技術研究所, 教授 (90013226)
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| Co-Investigator(Kenkyū-buntansha) |
NODA Takeshi Institute of Industrial Science, Research Associate, 生産技術研究所, 助手 (90251462)
TAKAHASHI Takuji Institute of Industrial Science, Associate Professor, 生産技術研究所, 助教授 (20222086)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Granular materials / quantum dots / anti-dots / Electron scattering / quantum rings / localization / Electron relaxation / nanostructures |
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| Research Abstract |
(1) As a model system of nano-scale semiconductor structures, we have grown and investigated self-organized InAs quantum dots and studied their various properties. Specifically, we have examined how some of the channel electronics in n-AlGaAs/GaAs heterojunctions are trapped by dots embedded in the proximity of the channel and how they are scattered and dephased by charged dots. We have examined also potentials of these systems for memory and photodetector applications, as trapped electrons in each dot can be erased by interband photo excitations. Dots can not only third neutralized, but also positively charged by trapping positive holes. Electron relaxations from the excited states to the ground level are also investigated and shown to be well described by polaron effects.
(2) To expand the research forefront of granular semiconductor structure, we have studied a series of dots formed in other material systems. In particular, AlGaSb dots embedded in GaAs quantum well is shown to induce a quantum ring state, as an electron is bound by a positively charged typeII dot system. Strained dots formed by InP islands on InGaAs well are found to show unique photo luminescence spectra, which are modulated by tera hertz radiations. Their device applications are discussed.
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