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Proceedings Paper

Variation of spectral response curves of GaAs photocathodes in activation chamber
Author(s): Jijun Zou; Benkang Chang; Zhi Yang; Hui Wang; Pin Gao
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Paper Abstract

The spectral response curves of reflection-mode GaAs (100) photocathodes are measured in activation chamber by multi-information measurement system at RT, and by applying quantum efficiency formula, the variation of spectral response curves have been studied. Reflection-mode GaAs photocathodes materials are grown over GaAs wafer (100) by MBE with p-type beryllium doping, doping concentration is 1×1019 cm-3 and the active layer thickness is 1.6μm. During the high-temperature activation process, the spectral response curves varied with activation time are measured. After the low-temperature activation, the photocathode is illuminated by a white light source, and the spectral response curves varied with illumination time are measured every other hour. Experimental results of both high-temperature and low-temperature activations show that the spectral response curve shape of photocathodes is a function of time. We use traditional quantum efficiency formulas of photocathodes, in which only the Γ photoemission is considered, to fit experimental spectral response curves, and find the theoretical curves are not in agreement with the experimental curves, the reason is other valley and hot-electron yields are necessary to be included in yields of reflection-mode photocathodes. Based on the two-minima diffusion model and the fit of escape probability, we modified the quantum efficiency formula of reflection-mode photocathodes, the modified formula can be used to explain the variation of yield curves of reflection-mode photocathodes very well.

Paper Details

Date Published: 6 October 2006
PDF: 7 pages
Proc. SPIE 6352, Optoelectronic Materials and Devices, 63523H (6 October 2006); doi: 10.1117/12.688725
Show Author Affiliations
Jijun Zou, Nanjing Univ. of Science and Technology (China)
East China Institute of Technology (China)
Benkang Chang, Nanjing Univ. of Science and Technology (China)
Zhi Yang, Nanjing Univ. of Science and Technology (China)
Hui Wang, Nanjing Univ. of Science and Technology (China)
Pin Gao, Nanjing Univ. of Science and Technology (China)

Published in SPIE Proceedings Vol. 6352:
Optoelectronic Materials and Devices
Yong Hee Lee; Fumio Koyama; Yi Luo, Editor(s)

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