Experimental determination of positron-related surface characteristics of 6H-SiC
Experimental determination of positron-related surface characteristics of 6H-SiC
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6H-SiC 正电子相关表面特性的实验测定
DOI：
10.1063/1.1435838
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发表时间：
2002
影响因子：
3.2
通讯作者：
G. Brauer
中科院分区：
文献类型：
--
作者：
A. Nangia;J. Kim;A. Weiss;G. Brauer
通过对表面再发射正电子能谱的分析，确定了6H-SiC的正电子功函数为−2.1±0.1 eV。用3keV，125keV AμA Min Ne+离子溅射后，样品的正电子再发射产额显著降低，其中正电子再发射产额最高的样品是经大气曝光和乙醇清洗后的样品。即使在90 0 °C下退火，成品率也没有恢复，这可能是由于溅射诱导缺陷的稳定性所致。在较低能量下溅射对再发射产额的影响较小，经850 °C热处理后，再发射产额基本恢复。用电子诱导俄歇电子能谱和正电子湮没诱导俄歇电子能谱分析表明，溅射后薄膜表面富硅，后续退火后表面富碳。根据再发射产额与束流能量的关系，求出了非溅射材料中正电子扩散长度和迁移率的值。并对碳化硅在涂料中的应用进行了展望。
The positron work function of 6H-SiC was determined to be −2.1±0.1 eV from an analysis of the energy spectrum of positrons reemitted from the surface. The positron reemission yield, highest in the sample inserted into vacuum after atmospheric exposure and cleaning with ethanol, was significantly reduced after sputtering with 3 keV, 125 μA min Ne+ ions. The yield was not recovered even after annealing at 900 °C, presumably due to the stability of sputter induced defects. Sputtering at lower energies caused a smaller decrease in the reemission yield that was largely recovered after annealing at 850 °C. Analysis using electron induced Auger electron spectroscopy and positron-annihilation-induced Auger electron spectroscopy indicated that the surface was Si enriched after sputtering and C enriched after subsequent annealing. Values of positron diffusion length and mobility in the unsputtered material were extracted from the dependence of the reemission yield on the beam energy. The application of SiC as a fie...