Simulation of kinetics of water temperature-programmed desorption from n-GaAs(100) and n-GaP(100) semiconductor surfaces

The energy spectra of adsorption centers on the n-GaAs(100) and n-GaP(100) surfaces are studied using temperature-programmed desorption of water. The desorption spectra are analyzed in terms of the model of discrete adsorption centers, which assumes the presence of a loosely bound precursor state. The values of frequency factors and activation energies of desorption are in good agreement with the frequency of electronic transitions and energies of surface electronic states in gallium arsenide and gallium phosphide. It is concluded that the water desorption kinetics is limited by slow electronic processes on the surface of the semiconductors.