Activation experiment of exponential-doping NEA GaAs photocathodes

An exponential-doping GaAs photocathode was designed and activated, the achieved integral sensitivity for the exponential-doping cathode is 1956μA/lm, which is much higher than that of gradient-doping cathode with identical thickness of epitaxial layer. According to the quantum efficiency theory of exponential-doping cathode, we analyzed the reason responsible for the increase in integral sensitivity of exponential-doping cathode, which are mainly attributed to the invariable induced electric field, the photoelectrons driven by the field move towards the cathode surface by way of diffusion and drift. Accordingly, increase the average distance that photoelectrons transport and reduce the influence of the back-interface recombination velocity on photoemission.

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