Crucial photoemission properties of layered III-V semiconductor cathodes are predicted using Monte Carlo simulations. Using this modeling, a layered GaAs structure is designed to reduce simultaneously the transverse energy and response time of the emitted electrons. This structure, grown by molecular beam epitaxy and activated to negative electron affinity, is characterized. The measured values of quantum efficiency and transverse energy are found to agree well with the simulations. Such advanced layered structures will allow generation of short electron bunches from photoinjectors with superior beam brightness.

GaAs with an atomic monolayer of Cs is one of the best known photoemissive materials. The results of density functional theory calculations of Cs adsorption on the GaAs(100)-(4×2) galliumterminated reconstructed surface and the GaAs(110) surface are presented in this work. Coverage of up to 4 Cs atoms/nm 2 on GaAs surfaces has been studied to predict the work function reduction and adsorption energies accurately. The high mobility of Cs atoms on the (110) surface allows formation of ordered structures, whereas the low mobility of Cs of the (100) surface causes amorphous growth.