Auger line-shape measurements have been made to extract the variation in the local charge distribution around Ga and As sites for chemisorption of oxygen on cleaved and sputter-etched GaAs(110). A significant variation with changing oxygen coverage is observed in the Ga spectrum, with a much more subtle change in the As spectrum. The kinetics of oxygen chemisorption on the sputter-etched surface is much more rapid than that on the cleaved surface. The line-shape changes induced by oxygen on the two surfaces are, however, similar. Conclusions on the nature of the bonding and on the mechanism for adsorption at both low and high coverages are drawn.

• Received 18 October 1983

DOI:https://doi.org/10.1103/PhysRevB.30.5742