Characteristic of surface barrier of epuably-doped GaAs photocathode

Zhang Liandong; Feng Liu; Liu Hui; Cheng Hongchang; Gao Xiang; Miao Zhuang

The photocathode surface barrier formation process of the GaAs photocathode was simulated according to the variation of the photocurrent while the photocathode was activating and in situ tests of spectra response, the two-dipole model was amended to establish a three dipole model. It was considered from the new model that the photocathode surface barrier formed by three kind of dipole layers, the first dipole layer was composed of GaAs(Zn)-Cs+ dipole, the second dipole layer was composed of Cs2O dipole and the third dipole layer was composed of GaAs-O-Cs dipole, the second and third dipole layer embedded in the first dipole layer. The barrier potential distribution which was piecewise uniform was established according to tunnel effect and results of quantum efficiency tests, it was calculated that the width of the barrier is 1.65 nm, and the effective electron affinity energy is -0.44 eV. The establishment of the new model is of great significance to further understand the photocathode surface emission mechanism.

1. Science and Technology on Low-Light-Level Night Vision Laboratory,Xi'an 710065,China;

2. North Night Vision Technology Group Co.,Ltd,Kunming 650223,China

Received Date: 2012-12-03

Rev Recd Date: 2013-01-10

Publish Date: 2013-08-25

Key words:

Abstract: The photocathode surface barrier formation process of the GaAs photocathode was simulated according to the variation of the photocurrent while the photocathode was activating and in situ tests of spectra response, the two-dipole model was amended to establish a three dipole model. It was considered from the new model that the photocathode surface barrier formed by three kind of dipole layers, the first dipole layer was composed of GaAs(Zn)-Cs+ dipole, the second dipole layer was composed of Cs2O dipole and the third dipole layer was composed of GaAs-O-Cs dipole, the second and third dipole layer embedded in the first dipole layer. The barrier potential distribution which was piecewise uniform was established according to tunnel effect and results of quantum efficiency tests, it was calculated that the width of the barrier is 1.65 nm, and the effective electron affinity energy is -0.44 eV. The establishment of the new model is of great significance to further understand the photocathode surface emission mechanism.

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Reference (11)

[1]	Liu Yuanzhen, Wang Zhongchun, Dong Yaqiang. Electron Emission and Photoelectricity Cathode[M]. Beijing: Beijing Institute of Technology Press, 1995. (in Chinese)刘元震, 王仲春, 董亚强. 电子发射与光电阴极[M]. 北京: 北京理工大学出版社, 1995.
[2]	Stocker B J. AES and LEED study of the activation of GaAs-Cs-O negative electron affinity surfaces[J]. Surface Science, 1975, 47: 501.
[3]	Uebbing J J, James L W. Behavior of cesium oxide as a low work-function coating[J]. Journal of Applied Physics, 1970, 41(11): 4505-4516.
[4]	Fisher D G, Enstrom R E, Escher J S, et al. Photoelectron surface escape probability of (Ga, In)As: Cs-O in the 0.9 to 1.6 m[J]. Journal of Applied Physics, 1972, 43(9): 3815-3823.
[5]	Gao Huairong. Investigation of the mechanism of the activation of GaAs negative electron affinity phototocathodes[J]. Journal of Vacuum Science Technology A, 1987, 5(4): 1295-1298.
[6]	Burt M G, Heine V J. The theory of the workfunction of caesium suboxides and caesium films[J]. Journal of Physics C: Solid State Physics, 1978, 11: 961-969.
[7]	Zou Jijun, Chang Benkang, Yang Zhi, et al. Variation of spectral response curves of GaAs photocathodes in activation chamber[C]//SPIE, 2006, 6352: 63523H-7.
[8]	Zong Zhiguo, Fu Rongguo, Qian Yunsheng, et al. Calculation of electron surface probability of GaAs:Cs-O NEA Photocathodes[J]. Infrared Technology, 2002, 24(3): 27-30. (in Chinese)宗志国, 富容国, 钱芸生, 等. GaAs:Cs-O NEA光电阴极电子表面逸出几率计算[J]. 红外技术, 2002, 24(3): 27-30.
[9]	Zhang Yijun, Niu Jun, Zhao Jing, et al. Effect of exponential-doping structure on quantum yield pf transmission-mode GaAs photocathodes[J]. Acta Phys Sin, 2011, 60: 067301. (in Chinese)张益军, 牛军, 赵静, 等. 指数掺杂结构对透射式GaAs光电阴极量子效率的影响研究[J]. 物理学报, 2011, 60: 067301.
[10]	Zhang Yijun, Zou Jijun, Niu Jun, et al. Photoemission characteristics of different-structure reflection-mode GaAs photocathodes[J]. Journal of Applied Physics, 2011, 110: 063113.
[11]	Benemanskaya G V, Daineka D V, Frank-Kamenetskaya G E. Changes in electronic and adsorption properties under Cs adsorption on GaAs(100) in the transition from As-rich to Ga-rich surface[J]. Surface Science, 2003, 523: 211-217.

Characteristic of surface barrier of epuably-doped GaAs photocathode

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