First principles investigation on the work function of osmium-coated Ba-W dispenser cathode

Os-coated barium-tungsten dispenser cathodes have attracted attention due to their low operating temperature, high current density and long lifetime. The tungsten in the substrate will continue to diffuse into the coating during the working process of the coated barium tungsten cathodes. In order to investigate the effect of Os coating on the emission performance of Ba-W dispenser cathodes, the work function of Os surface, Os-O-Ba surface, Os3W-O-Ba surface and W (Some atoms are replaced by Os atoms) - O-Ba surface were calculated by density functional theory (DFT). And the influence of Os on the emission properties of impregnated barium tungsten cathodes is discussed by the calculation results.