Research on photoemission and spectra response of NEA Ga1−xAlxN photocathodes

To improve the quantum efficiency of negative electron affinity (NEA) Ga1−xAlxN photocathodes, the photoemission process and performance parameters of the cathodes are discussed. According to “three-step” model, the influence of electron escape probability, electron diffusion length, and thickness of active layer on the quantum efficiency is simulated. Results show that increasing of electron escape probability and electron diffusion length is helpful for the t-mode and r-mode Ga1−xAlxN photocathodes. There exists an optimal thickness of active layer for the t-mode photocathodes, which is different from the r-mode one. This work lays a foundation for the design and preparation of NEA Ga1−xAlxN photocathodes.