PHOTOEMISSION YIELD STUDY OF THE FERMI-LEVEL POSITION ON THE CLEAN SNO2(110) SURFACE-EXPOSED TO OXYGEN

Electronic properties of the space charge layer of the clean SnO2(110) surface have been studied using photoemission yield spectroscopy (PYS ) associated with Auger electron spectroscopy (AES) and low energy ele ctron diffraction (LEED) control. Special attention has been paid to d etermination of the influence of ion bombardment cleaning as well as o xygen chemisorption. Depending on the annealing temperature and oxygen exposure, the variation of the Fermi level position was observed and analyzed together with the changes in the effective density of the fil led electronic states localized in the band gap below the Fermi level E(F) and in the upper part of the valence band. Two types of electroni c state bands were observed and attributed to the different types of s urface structural defects. (C) 1997 Elsevier Science Ltd.