UPS/XPS study of reactive and non-reactive SrTiO3 (100) surfaces: Adsorption of H2O

Abstract SrTiO 3 surfaces, prepared by ion bombardment alone and in conjunction with annealing, exhibit very different properties upon exposure to H 2 O. In the case of ion bombardment only, H 2 O adsorption occurs, signaled by the appearance of a peak in the Hell spectrum at 10.8 eV binding energy which saturates for dosages lower than 5 L. Our data indicate that this adsorption is non-dissociative. No adsorption was detected for bombarded and annealed samples. The difference in behavior is believed to be related to the oxidation state of Ti. The significance of these results for previously published data is discussed.