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 55.59: Poster
Mittwoch, 27. Februar 2008, 18:30–19:30, Poster F
The growth and structure of titania films on a rhenium(0001) surface — •Susanne Schubert and Klaus Christmann — Institut für Chemie und Biochemie der FU Berlin, Germany
In view of the significance of titanium dioxide as a catalyst support for low-temperature CO oxidation we have studied the epitaxy and chemical properties of titanium dioxide films grown on a clean and oxygen-covered Re(0001) surface. Titania films were prepared by co-deposition of Ti vapor in an oxygen atmosphere at elevated temperatures (T≥830K). The structure and chemical (surface) composition of these films were analyzed by means of low-energy electron diffraction (LEED), low-energy ion scattering (LEIS) and X-ray photoelectron spectroscopy (XPS) as a function of deposition rate and film thickness starting from the monolayer regime up to concentrations of 10 to 40 monolayers. While the overall film stoichiometry is close to TiO2 (rutile) independent of film thickness we find a moiré LEED pattern at low surface concentrations, faceting with hexagonal phases in three domains of rutile(110) rotated by 120∘ against each other in the medium coverage regime, and well-ordered unfaceted rutile films for thicknesses beyond ≈ 40 monolayers. The respective growth behavior can be described by a Stranski-Krastanov mechanism.