Electronic structure of SnO2(110)-4×1 and sputtered SnO2(110) revealed by resonant photoemission

The surface properties of SnO 2 (1 1 0)-4×1 and sputtered SnO 2 (1 1 0) were studied comparatively by resonant photoemission of the valence band states in a photon energy range of 60–130 eV. Resonating energetic levels could be observed on the 4×1 reconstructed surface and the resonance behavior could be switched off by sputter treatment. Additionally, the Sn 4d core-levels were recorded at two photon energies in order to allow a statement about the surface's stoichiometry. A tentative explanation of the observed resonance and of the discrepancy between ordered and sputtered surface is given with regard to recent STM results on similar prepared surfaces.