Comparison of the photoemission behaviour between negative electron affinity GaAs and GaN photocathodes  

作　　者：张益军 邹继军 王晓晖 常本康 钱芸生 张俊举 高频 

机构地区：[1]Institute of Electronic Engineering and Optoelectronic Technology,Nanjing University of Science and Technology

出　　处：《Chinese Physics B》2011年第4期532-537,共6页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 60801036 and 61067001);the Research and Innovation Plan for Graduate Students of Jiangsu Higher Education Institutions (Grant No. CX09B 096Z);the Research Foundation of Nanjing University of Science and Technology (Grant No. 2010ZYTS032)

摘　　要：In view of the important application of GaAs and GaN photocathodes in electron sources, differences in photoe- mission behaviour, namely the activation process and quantum yield decay, between the two typical types of III-V compound photocathodes have been investigated using a multi-information measurement system. The activation exper- iment shows that a surface negative electron affinity state for the GaAs photocathode can be achieved by the necessary Cs-O two-step activation and by Cs activation alone for the GaN photocathode. In addition, a quantum yield decay experiment shows that the GaN photocathode exhibits better stability and a longer lifetime in a demountable vacuum system than the GaAs photocathode. The results mean that GaN photocathodes are more promising candidates for electron source emitter use in comparison with GaAs photocathodes.In view of the important application of GaAs and GaN photocathodes in electron sources, differences in photoe- mission behaviour, namely the activation process and quantum yield decay, between the two typical types of III-V compound photocathodes have been investigated using a multi-information measurement system. The activation exper- iment shows that a surface negative electron affinity state for the GaAs photocathode can be achieved by the necessary Cs-O two-step activation and by Cs activation alone for the GaN photocathode. In addition, a quantum yield decay experiment shows that the GaN photocathode exhibits better stability and a longer lifetime in a demountable vacuum system than the GaAs photocathode. The results mean that GaN photocathodes are more promising candidates for electron source emitter use in comparison with GaAs photocathodes.

关 键 词：III-V photocathode negative electron affinity Cs-O activation quantum yield decay 

分 类 号：O472.8[理学—半导体物理]