1995 Fiscal Year Final Research Report Summary
Control of Optical Transitions with Quantum Microstructures of Indirect Semiconductors
| Project/Area Number |
06452103
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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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) |
FUKATSU Susumu Dept.of Pure and Appl.Sci., the University of Tokyo, Professor, 教養学部, 助教授 (60199164)
USAMI Noritaka RCAST,the University of Tokyo, Research Associate, 先端科学技術研究センター, 助手 (20262107)
OSADA Toshihito RCAST,the University of Tokyo, Lecturer, 先端科学技術研究センター, 講師 (00192526)
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| Project Period (FY) |
1994 – 1995
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| Keywords | SiGe / quantum well / quantum wire / quantum dot / neighboring confinement structure |
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| Research Abstract |
We investigated optical properties of indirect semiconductors with atomically controlled superstructures. By observing confinement effect and development of island-related emission with incerasing Ge coverage in Si/pure-Ge/Si quantum wells, the onset of the island formation was determined to be 3.7 monolayrs. Quantum confinement effect of island-related emission was clearly observed, demonstrating that the islands have "quantum dot" character. The island was found to generate inhomogeneous strain-field to the surrounding materials and to modulate potential. Formation of the Ge "quantum wire" at the step-edge was evidenced by plan-view transmission electron microscopy, enhanced exciton-exciton interactions, and incerased density of states at the band edge. A novel semiconductor superstructure, "Neighboring Confinement Structure (NCS)", to improve optical properties of indirect semiconductors was developed and successfully applied to SiGe-and ALGaP-based superstructures. Particularly, in the case of SiGe/Si system, luminescence without phonon participation was selectively enhanced, demonstrating the potential of NCS as light emitters.
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