Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Poster Session III - MA 141/144 (Methods: Atomic and Electronic Structure; Particles and Clusters; Heterogeneous Catalysis; Semiconductor Substrates: Epitaxy and Growth+Adsorption+Clean Surfaces+Solid-Liquid Interfaces; Oxides and Insulators: Solid-Liquid Interfaces+Epitaxy and Growth; Phase Transitions; Metal Substrates: Adsorption of Inorganic Molecules+Epitaxy and Growth; Surface Chemical Reactions; Bimetallic Nanosystems: Tuning Physical and Chemical Properties; Oxides and insulators: Adsorption; Organic, polymeric, biomolecular films; etc.)

O 55.35: Poster

Mittwoch, 27. Februar 2008, 18:30–19:30, Poster F

Post annealing investigations of thin praseodymia films on Si(111) — Sebastian Gevers, •Daniel Bruns, Thomas Weisemöller, Carsten Deiter, and Joachim Wollschläger — Fachbereich Physik, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany

Due to its large oxygen capacity and oxygen mobility praseodymia is interesting for applications in modern heterogenous catalysis. For instance the selectivity of praseodymia for carbon compounds is advantageous in olefiant gas synthesis. The investigation of annealing processes leads to a better understanding of the oxygen transport in the praseodymia films. In this context thin PrO2 films were annealed at temperatures from 300°C up to 600°C under UHV conditions before they were analysed with Spot Analysis Profile Low Electron Energy Diffraction (SPALEED). The diffraction pattern indicates a phase transition to Pr2o3 at the surface. Furthermore X-Ray Diffraction experiments (XRD) show a partial subsurface phase transition from PrO2 into various oxidation states including Pr2O3.