Physical Properties of Nano-size Pore Surfaces and Metal Films on Pore Surfaces of Porous Silicon
| Project/Area Number |
05650024
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
表面界面物性
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| Research Institution | Tokyo Gakugei University |
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Principal Investigator |
MURAKAMI Hideoki Tokyo Gakugei University, Department of Education, Professor, 教育学部(第三部), 教授 (30011000)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1994: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1993: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Surface Science / Porous Silicon / Positronium / Positron |
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| Research Abstract |
The yield of ortho-positroniums with a lifetime of a few ten nanosecond, which is shortened upon exposure to oxygen gas, has been found in a porous silicon made by anodization of a silicon single crystal of 2.0OMEGAcm. The lifetime becomes long from 33ns to 45ns, and the full width at half maximum of the Doppler-broadened annihilation radiation increases, as the temperatere is decreases from 300 K to 85 K,and both of them level off at temperatures lower than 85 K.The intensity of ortho-positroniums decreases from 22 % to 15 % as the temperature goes down from 300 K to extrapolated 0 K.Temperature-dependent positronium annihilation is understood in terms of the temperature dependence of unpaired electron density on pore surfaces.
The formation of ortho-positroniums has not been found in a porous silicon made with a silicon single crystal of 0.02 OMEGAcm. No positronium formation has been explained mainly on the low surface density.
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Report
(3 results)
Research Products
(9 results)
