1997 Fiscal Year Final Research Report Summary
Research on Optical Transitions of Indirect Semiconductors with Novel Superstructures
| Project/Area Number |
08455008
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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 | The University of Tokyo |
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Principal Investigator |
SHIRAKI Yasuhiro RCAST,the University of Tokyo, Professor, 先端科学技術研究センター, 教授 (00206286)
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| Co-Investigator(Kenkyū-buntansha) |
USAMI Noritaka The University of Tokyo, RCAST,Research Associate, 先端科学技術研究センター, 助手 (20262107)
YAGUCHI Hiroyuki The University of Tokyo, Faculty of Engineering, Research Associate, 大学院・工学系研究科, 助手 (50239737)
KONDO Takashi The University of Tokyo, Faculty of Engineering, Professor, 大学院・工学系研究科, 助教授 (60205557)
ONABE Kentaro The University of Tokyo, Faculty of Engineering, Professor, 大学院・工学系研究科, 教授 (50204227)
ITO Ryoichi The University of Tokyo, Faculty of Engineering, Professor, 大学院・工学系研究科, 教授 (40133102)
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| Project Period (FY) |
1996 – 1997
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| Keywords | SiGe / AlGaP / indireck semiconductors / neighboring confinement structure / no phonon transition |
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| Research Abstract |
Optical properties of Neighboring Confinement Structure (NCS), a promising candidate for light emitter based on indirect semiconductors, were systematically investigated. NCS consists of a single pair of a quantum well (QW) for electrons and a QW for holes embedded between barrier layrs. Intense PL with enhanced no-phonon (NP) line was clealy observed from NCS based on SiGe- and AlGaP-based semiconductors. Quantum confinement effect was clearly observed by varying the well width, showing that the enhanced NP lines come from the expected transitions of the NCS.Post growth annealing was found to lead to selective quenching of the NP line compared to its transverse optical phonon replica. Time-resolved PL study clarified that the radiative lifetime of the annealed sample increases with increasing temperature, while that of the as-grown sample shows no significant change at low temperatures. These results were reasonably explained by considering that the exciton localization at the heterointerface is the controlling mechanism for the NP enhancement observed at low temperatures in NCS.The idea was supported by the increase of the critical temperature of the exciton delocalization in the sample with well width of around critical thickness for islanded growth where well width fluctuation is considered to be significant.
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