Physical Properties of Nano-size Pore Surfaces and Metal Films on Pore Surfaces of Porous Silicon

多孔硅纳米孔表面及孔表面金属膜的物理性能

• 批准号: 05650024
• 负责人: MURAKAMI Hideoki
• 金额: $ 1.34万
• 依托单位: Tokyo Gakugei University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05650024/
• 关键词: Surface Science; Porous Silicon; Positronium; Positron

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.

在多孔硅中发现了寿命为几十纳秒的正电子正电子产额，这种正电子产额在暴露于氧气中时会缩短。当温度从300K降低到85K时，正电子强度从22%下降到15%。正电子强度从300K下降到外推0K时，正电子强度从22%下降到15%。正电子湮没随温度的变化可以用未成对电子密度对孔表面温度的依赖关系来理解。在0.02OmeGm的多孔硅中没有发现正电子的形成。没有正电子的形成主要是由于表面密度较低。

项目成果

Y.Itoh,H.Murakami and A.Kinoshita: "Positronium formation and annihilation in porous silicon" Proceedings of Internal Conference of Positron Annihilation. (in press). (1995)

Y.Itoh、H.Murakami 和 A.Kinoshita：“多孔硅中的正电子形成和湮灭”正电子湮灭内部会议论文集。

Y.Itoh,H.Murakami and A.Kinoshita: "Positron annihilation study on nanometer cavities in porous silicon" Hyperfine Interactions. 84. 121-126 (1994)

Y.Itoh、H.Murakami 和 A.Kinoshita：“多孔硅纳米腔的正电子湮没研究”超精细相互作用。

Y. Itoh, H. Murakami and A. Kinoshita: "Positronium formation and annihilation in porous silicon" Materials Science Forum. 175-178 (in press). (1995)

Y. Itoh、H. Murakami 和 A. Kinoshita：“多孔硅中正电子的形成和湮灭”材料科学论坛。

Y. Itoh, H. Murakami and A. Kinoshita: "Positron annihilation study on nanometer cavities in porous silicon" Hyperfine Interactions. 84. 121-126 (1994)

Y. Itoh、H. Murakami 和 A. Kinoshita：“多孔硅纳米腔的正电子湮没研究”超精细相互作用。

Y.Itoh,H.Murakami and A.Kinoshita: "Positron annihilation in porous silicon" Applied Physics Letters. 63. 2798-2799 (1993)

Y.Itoh、H.Murakami 和 A.Kinoshita：“多孔硅中的正电子湮灭”应用物理快报。