| Project/Area Number |
07650973
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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 |
工業分析化学
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
NOMURA Kiyoshi THE UNIVERSITY OF TOKYO GRADUATE SCHOOL OF ENGINEERING RESEARCH ASSOCIATE, 大学院・工学系研究科, 助手 (40124680)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1995: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | ^<119>Sn Mossbauer spectra, / Conversion electron detectors, / Glancing angle CEMS, / Grazing incident CEMS, / ITO transparent and conductive powder and films, / A gas sensor of SnO_2 implanted with Au and Fe ions. |
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| Research Abstract |
The purpose of our research is to develop a glancing angle conversion electron Mossbauer spectroscopy (GACEMS), which can be applied to the analysis of tin states in the thinner surface layrs of transparent semiconductors and gas sensors materials. Since the range of internal conversion electrons (19.6 keV) emitted after ^<119>Sn Mossbauer effect is large (about 2 mum in solid), the sensitivity of thin surface by a conventional method was small. A back scattered gas flow counter for GACEMS was designed so that the gamma rays of ^<119>Sn could be irradiated on the surface at low glancing angles (<5^0). Since the measuring time was so long, the measuring system was also improved so as to get three or four spectra simultaneously by detecting the conversion electrons with different energy. On the other hand, the chemical states of Sn in Sn-doped In_2O_3 (ITO) powders and films were reestimated by a point charge approximation and Mossbauer spectrometry. It was found that there are 7-and 8-fold coordinated, electrically inactive Sn^<4+> species in the ITO lattice in addition to two electrically active Sn^<4+> species. The estimated carrier densities by Mossbauer spectra were in good agreement with the measured values. Gas sensor properties of SnO_2 films implanted with Au and Fe ions also were studied, and will be characterized by CEMS.Further, the applications of CEMS to various fields have been reviewed.
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