Energy threshold of Cs-induced chemisorption of oxygen on a GaAs(Cs, O) surface

The probability of Cs-induced chemisorption of oxygen on a p-GaAs(Cs, O) surface is experimentally shown to be close to unity only when the work function does not exceed ~3.1 ± 0.1 eV. The measured adsorption energy threshold likely corresponds to the energy of the unoccupied level of the antibonding 2π* orbital of the O₂ molecule in the preadsorption state on the semiconductor surface.