Cs/O co-adsorption on C-doped GaAs surface: From first-principles simulation to experiment

C-doped GaAs is considered a potential material for negative electron affinity photocathodes, where the p-type doped property is beneficial to photoemission. To clarify the stability and efficiency during Cs/O activation, the gradient concentration of Cs adsorption and Cs/O co-adsorption models of C-doped GaAs are established. The work function, adsorption energy, and surface dipole moment are intensified by first principles calculation based on density functional theory. Experimental results demonstrate that Cs/O activation effectively enhances the performance of C-doped GaAs photocathodes, resulting in high levels of quantum efficiency. Therefore, we conclude that C-doped GaAs photocathodes have the potential to significantly improve the photoelectric emission performance and stability of GaAs photocathodes, making them a viable candidate for future applications.