Quantum Yield of Reflection Mode Varied Doping GaN Photocathode
School of Electronic and Electrical Engineering, Nanyang Institute of Technology, NanYang 473004 China
Using the NEA photocathode activation and evaluation experiment system, the varied doping GaN photocathode has been activated and evaluated. According to the diffusion and orientation drifting equation, the quantum yield formula of reflection mode varied doping NEA GaN photocathode was gotten. The factors affecting the quantum efficiency of varied doping GaN photocathode were studied. For the varied doping GaN photocathode, the quantum efficiency is mainly decided by the escape probability of electron P, he absorption coefficient α, the electron diffuse length LD, the reflectance of cathode materials for incident light R, emission layer thickness Te and the inside electric field E. The experiment and analysis results show: With the directional inside electric field in the bulk, the varied doping NEA GaN photocathode has better photoemission performance than uniform doping photocathode.
© The Authors, published by EDP Sciences, 2016
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