中国物理B ›› 2012, Vol. 21 ›› Issue (3): 34214-034214.doi: 10.1088/1674-1056/21/3/034214

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陈亮1 2,钱芸生2,张益军2,常本康2   

  • 收稿日期:2011-01-13 修回日期:2011-08-23 出版日期:2012-02-15 发布日期:2012-02-15
  • 通讯作者: 陈亮,sunembed@yahoo.com.cn E-mail:sunembed@yahoo.com.cn

Comparative research on the transmission-mode GaAs photocathodes of exponential-doping structures

Chen Liang(陈亮)a)b)†, Qian Yun-Sheng(钱芸生)b), Zhang Yi-Jun(张益军)b), and Chang Ben-Kang(常本康)b)   

  1. a. Institute of Optoelectronics Technology, China Jiliang University, Hangzhou 310018, China;
    b. Institute of Electronic Engineering & Optoelectronics Technology, Nanjing University of Science and Technology, Nanjing 210094, China
  • Received:2011-01-13 Revised:2011-08-23 Online:2012-02-15 Published:2012-02-15
  • Contact: Chen Liang,sunembed@yahoo.com.cn E-mail:sunembed@yahoo.com.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 60678043 and 60801036).

Abstract: Early research has shown that the varied doping structures of the active layer of GaAs photocathodes have been proven to have a higher quantum efficiency than uniform doping structures. On the basis of our early research on the surface photovoltage of GaAs photocathodes, and comparative research before and after activation of reflection-mode GaAs photocathodes, we further the comparative research on transmission-mode GaAs photocathodes. An exponential doping structure is the typical varied doping structure that can form a uniform electric field in the active layer. By solving the one-dimensional diffusion equation for no equilibrium minority carriers of transmission-mode GaAs photocathodes of the exponential doping structure, we can obtain the equations for the surface photovoltage (SPV) curve before activation and the spectral response curve (SRC) after activation. Through experiments and fitting calculations for the designed material, the body-material parameters can be well fitted by the SPV before activation, and proven by the fitting calculation for SRC after activation. Through the comparative research before and after activation, the average surface escape probability (SEP) can also be well fitted. This comparative research method can measure the body parameters and the value of SEP for the transmission-mode GaAs photocathode more exactly than the early method, which only measures the body parameters by SRC after activation. It can also help us to deeply study and exactly measure the parameters of the varied doping structures for transmission-mode GaAs photocathodes, and optimize the Cs-O activation technique in the future.

Key words: GaAs photocathode, surface photovoltage, electron diffusion length, surface escape probability

中图分类号:  (Light-sensitive materials)

  • 42.70.Gi
71.55.Eq (III-V semiconductors) 72.10.-d (Theory of electronic transport; scattering mechanisms)