Acta Photonica Sinica, Volume. 48, Issue 9, 925001(2019)
Microarea Analysis of Surface Contaminations of GaAs Photocathode in Preparation Process
Based on the ultrahigh vacuum interconnection setup for photocathode preparation and surface analysis, the activation experiments were performed on reflective GaAs photocathodes, and the microarea analysis of the photocathodes after chemical cleaning and Cs/O activation was implemented by the scanning focused Xray photoelectron spectroscopy. Micro regions of interest were located to be detected with the aid of the Xray beam induced secondary electron image, and the impurities on the surface were analyzed more accurately. It is found that the GaAs cathode samples after chemical cleaning would suffer from secondary contamination by the metal sheet, accompanied by a small amount of sodium and cesium. Surface analysis and activation experiments show that high temperature heating and Cs/O activation can not remove the sodium contamination, which can affect the desorption of arsenic on the surface, hinder the adsorption of Cs and O in the activation process, and finally reduce the photoemission performance of the activated cathode. The scanning focused Xray imaging technology is used to analyze the microarea of cathode surface, which would assist in investigating the change of surface composition before and after cathode activation more accurately.
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FANG Chengwei, ZHANG Yijun, RONG Minmin, QIAN Yunsheng, DAI Qingxin, SHI Feng, CHENG Hongchang, BAI Xiaofeng. Microarea Analysis of Surface Contaminations of GaAs Photocathode in Preparation Process[J]. Acta Photonica Sinica, 2019, 48(9): 925001
Received: Apr. 8, 2019
Accepted: --
Published Online: Oct. 12, 2019
The Author Email: Chengwei FANG (1184430970@qq.com)