Observations of Electron Emission sites on Alumina Surface by using a Photoelectron Emission Microscope

使用光电子发射显微镜观察氧化铝表面的电子发射位点

基本信息

批准号：
11650279
负责人：
KOBAYASHI Shinichi
金额：
$ 2.24万
依托单位：
Saitama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Electron emission sites on alumina surfaces have been observed by a photoelectron emission microscope (PEEM). Surface flashover is an obstacle to minimize the size of electric power devices, since surface flashover voltage on an insulator surface is fairy lower than that of gap breakdown voltage of the same gap lemgth. Surface flashover is dominated by electron emission from triple junctions and subsequent electron emission from the insulator surface. Electron emission properties from insulator surface have not been clarified yet. In this project, photoelectron emissionsites excited by ultraviolet light were observed. Maximum energy of the irradiated ultraviolet light was about 11 eV, which is greater than the band gap of alumina.Observations revealed that photoelectron emission sites on alumina surface were localized (diameter < few μm) and the emission took place not continuously, but intermittently. This electron emission schem is quite different from that from metals, since the electron emission site expands over the who ; e area where excitation light was irradiated and electrons are emitted continuously. Also revealed by the observations was that lower energy of excitation light that that of the band gap of alumina could excite phoelectreon emission. This result confirms that energy bands created by crystal defects are formed in the band gap.Further experiments to explain these electron emission properties from an insulator surface should be performed, on the basis of charging property, elemental analysis at the localized sites, and electronic states.

光电子发射显微镜（PEEM）观察到了氧化铝表面上的电子发射位点。表面闪光灯是最大程度地减少电力设备尺寸的障碍，因为绝缘子表面上的表面闪存电压低于相同间隙弯曲的间隙故障电压的童话。表面闪光灯以从三重连接的电子发射和随后从绝缘体表面发射的电子发射为主。尚未阐明来自绝缘体表面的电子发射特性。在这个项目中，观察到了通过紫外线激发的光电发射位点。辐照的紫外线的最大能量约为11 eV，大于氧化铝的带隙。观察表明，氧化铝表面上的光电子发射位点被定位（直径<少数μm），并且发射不连续，但间歇性地进行。由于电子发射位点在WHO上扩展，因此该电子发射方案与金属大不相同。 E辐照兴奋光并连续排放电子的区域。观察结果还表明，氧化铝带隙的兴奋光能较低的能量可能会激发菲洛因发射。该结果证实了由晶体缺陷产生的能带在带间隙中形成的。