The behavior of charge transfer and oxidation of GaAs(110) substrates, covered with potassium and/or oxygen, and after thermal treatment, is investigated by Auger and photoelectron spectroscopy, work-function measurements, and low-energy electron diffraction. The oxidation of GaAs(110) is efficiently promoted by the presence of K adatoms. The experimental results indicate that both the charge transfer from the K atoms to the substrate and the formation of several potassium oxides may be the crucial factors for the enhancement of the substrate oxidation.

• Received 31 January 1989

DOI:https://doi.org/10.1103/PhysRevB.39.12751