GaAs光电阴极制备工艺中表面污染的微区分析  

Micro-area Analysis of Surface Contaminations of GaAs Photocathode in Preparation Process

作　　者：方城伟 张益军[1] 荣敏敏 钱芸生[1] 戴庆鑫 石峰 程宏昌 拜晓峰 FANG Cheng-wei;ZHANG Yi-jun;RONG Min-min;QIAN Yun-sheng 1;DAI Qing-xin;SHI Feng;CHENG Hong-chang;BAI Xiao-feng(School of Electronic and Optical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;Science and Technology on Low-Light-Level Night Vision Laboratory,Xi’an 710065,China)

机构地区：[1]南京理工大学电子工程与光电技术学院,南京210094 [2]微光夜视技术重点实验室,西安710065

出　　处：《光子学报》2019年第9期35-41,共7页Acta Photonica Sinica

基　　金：国家自然科学基金(Nos.61771245,61301023);微光夜视技术重点实验室基金(No.J20150702)~~

摘　　要：基于超高真空光电阴极制备与表面分析互联装置开展了反射式GaAs光电阴极激活实验,并利用扫描聚焦X射线光电子能谱对化学清洗后及Cs/O激活后的阴极表面进行了微区分析.通过X射线激发样品产生二次电子图像定位需要分析的微小区域,更加准确地检测了阴极表面存在的杂质.检测发现化学清洗后的GaAs阴极样品会受到金属压片的二次污染,出现钠、铯污染.表面分析和激活实验表明,高温加热和激活并不能去除钠污染,且此污染会影响表面砷的脱附,阻碍激活过程中Cs、O的吸附,降低阴极的光电发射性能.采用扫描聚焦X射线成像技术对阴极表面进行微区选点分析,有助于更加准确地分析阴极激活前后的表面成分变化.Based on the ultra-high vacuum interconnection setup for photocathode preparation and surface analysis,the activation experiments were performed on reflective GaAs photocathodes,and the micro-area analysis of the photocathodes after chemical cleaning and Cs/O activation was implemented by the scanning focused X-ray photoelectron spectroscopy.Micro regions of interest were located to be detected with the aid of the X-ray 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 X-ray imaging technology is used to analyze the micro-area of cathode surface,which would assist in investigating the change of surface composition before and after cathode activation more accurately.

关 键 词：GAAS光电阴极 扫描聚焦X射线成像技术 微区分析 表面污染 光电发射 

分 类 号：TN223[电子电信—物理电子学]