22 October 2010 Spectral response variation of exponential-doping transmission-mode GaAs photocathodes in the preparation process
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The exponential-doping structure was applied to prepare the transmission-mode GaAs photocathode, and spectral response curves after high-temperature activation, low-temperature activation and the indium sealing process were respectively measured by use of the on-line spectral response measurement system, to research into the practical effect of the exponential-doping structure on cathode performance. The results show that a high photosensitivity ranging from 560 nm to 880 nm with an ascending trend can be obtained after the high-low temperature activation. In the region of longwave threshold, there is a distinct inflexion indicating a better photoemission capability than the former uniform-doping photocathodes. Besides, the spectral response curve in the whole response waveband, especially the long-wave region obviously decreases after indium seal. Compared with the fitted surface electron escape probability after Cs-O activation, it decreases after indium seal according to the quantum efficiency formula of exponential-doping transmission-mode GaAs photocathodes. Based on the double dipole model, the reasons for the variation of spectral response shape are explained on account of the relation between surface escape probability and the evolution of surface potential barrier profile.
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Yijun Zhang, Yijun Zhang, Jun Niu, Jun Niu, Benkang Chang, Benkang Chang, Yajuan Xiong, Yajuan Xiong, Zhi Yang, Zhi Yang, Yujie Du, Yujie Du, "Spectral response variation of exponential-doping transmission-mode GaAs photocathodes in the preparation process", Proc. SPIE 7658, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology, 765841 (22 October 2010); doi: 10.1117/12.864180; https://doi.org/10.1117/12.864180

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