Photoemission from advanced heterostructured Al_xGa_1-xAs/GaAs photocathodes under multilevel built-in electric field

• DOI: 10.1364/oe.23.019478
• Publication Date: 2015-07-17T23:06:44Z
• Authors: Cheng Feng; Yijun Zhang; Yunsheng Qian; Benkang Chang; Feng Shi; Gangcheng Jiao; Jijun Zou
• Keywords: Photocathode; Quantum Efficiency; Photoelectric effect

A heterostructured Al(x)Ga(1-x)As/GaAs photocathode consisting of a composition-graded buffer layer and an exponential-doped emission is developed to improve the photoemission performance over wavelength region interest. The theoretical quantum efficiency models for reflection-mode transmission-mode photocathodes are deduced based on one-dimensional continuity equations, respectively. By comparison simulated results with conventional models, it found that multilevel built-in electric field can effectively efficiency, which related parameters cathode thicknesses. This special graded bandgap structure arising from compositional grade in doping would bring about reduction back interface recombination losses efficient collection photons generating photoelectrons. Moreover, best fit experimental data be achieved aid provide effective approach evaluate internal photoemitters.