Berlin 2008 – scientific programme

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O: Fachverband Oberflächenphysik

O 32: Oxides and Insulators: Clean Surfaces

O 32.3: Talk

Tuesday, February 26, 2008, 13:30–13:45, MA 042

Direct Observation of d²L² Charge Transfer States in TiO₂ thin films by Resonant Photoelectron Spectroscopy — •Sebastian Müller and Dieter Schmeisser — Brandenburgische Technische Universität Cottbus, Angewandte Physik - Sensorik, Konrad-Wachsmann-Allee 17, 03046 Cottbus, Germany

We investigate the electronic structure of TiO₂ thin films by SR-PES, NEXAFS and ResPES. The films are prepared in a combined in-situ/ex-situ process that leads to stoichiometric thin films (≈ 10 nm) in Rutile structure. We focus on ResPES at the Ti 2p edge. When the photon energy is close to the Ti 2p absorption edge we observe additional features about 13 eV below the valence band main features. These features show clear spectator auger decay at the resonance leading to d⁰ final state. From this, we deduce the existence of the d²L² initial charge transfer state as this is the only possible channel that enables the corresponding spectator auger decay. These features have the same origin as the satellite structures observed in core level spectra, esp. 2p and 3p.