2005 Fiscal Year Final Research Report Summary
High efficient photoluminescence from isoelectric impurities in quantum confined Si nanocrystals
| Project/Area Number |
15510091
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nanostructural science
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| Research Institution | Kobe University |
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Principal Investigator |
FUJII Minoru Kobe University, Faculty of Engineering, associate Professor, 工学部, 助教授 (00273798)
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| Co-Investigator(Kenkyū-buntansha) |
HAYASHI Shinji Kobe University, Faculty of Engineering, Professor, 工学部, 教授 (50107348)
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| Project Period (FY) |
2003 – 2005
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| Keywords | luminescence / silicon / nanocrystal / doping |
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| Research Abstract |
The purpose of this work is to form an isoelectric trap in Si nanocrystals by simultaneously doping n and p type impurities. We have developed a method to prepare P and B codoped Si nanocrystals, and studied the optical properties in detail as functions of P and B concentration. The photoluminescence intensity of carrier-compensated Si nanocrystals was larger than that of either n or p type impurity doped Si nanocrystals, and sometimes it was larger than that of pure Si nanocrystals. Furthermore, the tunable range of photoluminescence energy is extended to below the bandgap energy of bulk Si crystals. By properly controlling the impurity concentration and size of Si nanocrystals, the photoluminescence energy was controlled from 0.9eV to 1.5eV without losing the intensity so much. The carrier compensated Si nanocrystals also act as an efficient photo-sensitizer for rare-earth ions. It has been demonstrated that the carrier compensated Si nanocrystals can excite Er ions placed nearby quite efficiently. The photoluminescence intensity of Er ions in carrier-compensated Si nanocrystals was larger than that in pure Si nanocrystals.
Although we could successfully demonstrate that the formation of isolectric centers in Si nanocrystals is possible and these nanocrystals exhibit characteristic features, which are absent in pure Si nanocrystals, the electronic structures of impurity doped Si nanocrystals are still not fully clarified. In order to extend the functionality of Si nanocrystals and explore the applications, deeper understanding of the electronic structures is indispensable, and will be a target of future research.
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