| Project/Area Number |
11650315
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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 |
Electronic materials/Electric materials
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
WATANABE Masahiro Department of Information Processing, Tokyo Institute of Technology. Associate Professor, 大学院・総合理工学研究科・物理情報システム創造専攻, 助教授 (00251637)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1999: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Zinc oxide / Calcium fluoride / epitaxial growth / Ultra violet / photoluminescence / current injection luminescence / nanocrystal / photonic materal / ナノクリスタルシリコン / 量子閉じこめ効果 / フォトルミネッセンス / 電流注入発光 |
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| Research Abstract |
The purpose of this study is to demonstrate light emitting properties originated from nanometer size crystals formed in single crystalline calcium fluoride (CaF_2), which is a wide band gap ionic material grown on silicon substrate. In such kind of material systems, strong quantum confinement can be expected due to large conduction band discontinuity at the heterointerface, which leads fascinating changes of electron photon interaction from the bulk material.
Results obtained in this study are as follows.
i) Formation technique of nanocrystalline zinc oxide (ZnO) on CaF_2/Si (111) substrate has been developed using RF sputtering followed by regrowth of CaF_2 by molecular beam epitaxy. Growth temperature, background pressure, RF power and post annealing condition was optimized.
ii) Ultra-violet photoluminescence at wavelength of 380 nm and electroluminescence was observed at room temperature. Transmission electron microscopy (TEM) lattice image clearly confirmed that sharp heterointerface of CaF_2/ZnO/CaF_2 was formed. Growth condition was optimized by luminescence intensity and surface morphology.
iii) Thermal annealing process in oxygen or ultra-high vacuum was introduced for improving luminescence intensity. Dependence of luminescence on annealing temperature, time, pressure was clarified.
iv) Current injection luminescence was demonstrated using current restriction structure with transparent conducting ITO electrode fabricated using photolithography and dry etching. UV luminescence was clearly observed at room temperature and the luminescence was stable. From this result, nanocrystalline ZnO embedded in single crystalline CaF_2 has stable heterointerface, which is atractive for UV photonic materials on silicon substrate.
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