中国物理B ›› 2011, Vol. 20 ›› Issue (4): 48501-048501.doi: 10.1088/1674-1056/20/4/048501

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

张益军, 邹继军, 王晓晖, 常本康, 钱芸生, 张俊举, 高频   

  1. Institute of Electronic Engineering and Optoelectronic Technology, Nanjing University of Science and Technology, Nanjing 210094, China
  • 收稿日期:2010-10-26 修回日期:2010-12-01 出版日期:2011-04-15 发布日期:2011-04-15
  • 基金资助:
    Project 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_

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

Zhang Yi-Jun(张益军),Zou Ji-Jun(邹继军),Wang Xiao-Hui(王晓晖), Chang Ben-Kang(常本康)†, Qian Yun-Sheng(钱芸生), Zhang Jun-Ju(张俊举),and Gao Pin(高频)   

  1. Institute of Electronic Engineering and Optoelectronic Technology, Nanjing University of Science and Technology, Nanjing 210094, China
  • Received:2010-10-26 Revised:2010-12-01 Online:2011-04-15 Published:2011-04-15
  • Supported by:
    Project 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), and the Research Foundation of Nanjing University of Science and Technology (Grant No. 2010ZYTS032).

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摘要： In view of the important application of GaAs and GaN photocathodes in electron sources, differences in photoemission 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 experiment 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

Abstract: In view of the important application of GaAs and GaN photocathodes in electron sources, differences in photoemission 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 experiment 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.

Key words: III–V photocathode, negative electron affinity, Cs–O activation, quantum yield decay

中图分类号:  (Photomultipliers; phototubes and photocathodes)

  • 85.60.Ha
73.61.Ey (III-V semiconductors) 73.20.At (Surface states, band structure, electron density of states) 79.60.-i (Photoemission and photoelectron spectra)