Regensburg 2010 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 10: Dielectric surfaces and interfaces
DF 10.5: Vortrag
Mittwoch, 24. März 2010, 15:45–16:05, H11
In situ high pressure synchrotron photoemission study of the SrTiO3/Pt interface — •Robert Schafranek1, Christoph Körber1, Andre Wachau1, Andreas Klein1, Michael Haväcker2, Axel Knop-Gericke2, and Robert Schlögl2 — 1Darmstadt University of Technology, Institute of Materials Science, Surface Science Division, Petersenstrasse 23, D-64287 Darmstadt, Germany — 2Fritz-Haber Institute, Department of Inorganic Chemistry, Faradayweg 4-6, 14195 Berlin, Germany
The (Ba,Sr)TiO3/Pt interface present e.g. in tunable capacitors for microwave applications plays a crucial role for device properties, which can be explained by a variation of the Schottky barrier height with preparation conditions. It has been shown by photoemission experiments that the barrier height can be reversibly switched between a reduced state with a low barrier height ( 0.5 eV) and an oxidized state with a high barrier height (>1.2 eV) by annealing at 400∘C in vacuum and oxygen, respectively. An in situ high pressure synchrotron photoemission study of the SrTiO3/Pt interface was carried out for further understanding of the dependence of the Schottky barrier height on the O2 pressure. The experiments were performed at the ISISS dipole beamline at the BESSY II synchrotron in Berlin at different temperatures using a SrTiO3:Nb single crystal covered with a 3 nm thick Pt layer. A modification of the barrier height of 1eV could be observed even for the lowest used sample temperature of 100 ∘C. Furthermore the variation of the barrier height with O2 pressure could be verified by O2 pressure-dependent I-V measurements.