The oxidation process of the K/GaAs(110) interface

The K-promoted oxidation of GaAs(110) has been studied using Auger electron spectroscopy and principal component analysis. We found that the oxidation process of the interface is not a properly catalytic mechanism, as the alk ali metal reacts forming compounds that become mixed with the substrate oxi dation products. The substrate oxidation process starts, as well as that fo r the adsorbate, from the beginning of the oxygen exposure without showing an adsorption stage like that observed during the oxidation process of the clean GaAs surface. The alkali-promoted oxidation of GaAs involves the simu ltaneous oxidation of all the elements present, K, As and Ga, and neither i nduction nor adsorption stages are observed.