GaAs cathode activation with Cs-K-Sb thin film

Abstract GaAs cathodes are unique devices which generate a spin-polarized electron beam by the photoelectric effect when illuminated with a circularly polarized laser. Thin-film Negative Electron Affinity (NEA) surfaces have an essential role in spin polarized beam production, but they have limited lifetimes. In this study, we activate GaAs as an NEA cathode by evaporating Cs, K, and Sb metal on its cleaned surface. The experimental results of quantum efficiency measurements taken after evaporative deposition of the multi-alkali surface are presented here.