Photoemission studies of K-promoted oxidation of the GaAs(110) surface

Core-level and valence-band photoemission have been used to investigate oxi dation at the K/GaAs(100) interface. The results show that potassium deposi ted on the top of a substrate forms a polarized layer. The K-promoted oxida tion mainly involves As. The initial bonds between an alkali metal and a se miconductor have less of a relation with the amount of adsorbed oxygen, but the disruption of K-As bonds restores a large density of As dangling bonds , and the adsorbed oxygen coupling of these dangling bonds leads to the out -of-proportional function of the As oxide. (C) 2000 American Vacuum Society . [S0734-2101(00)01402-0].