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DS: Fachverband Dünne Schichten

DS 6: Thin Film Characterization: Structure Analysis and Composition (XRD, TEM, XPS, SIMS, RBS,...)

DS 6.10: Vortrag

Montag, 31. März 2014, 17:30–17:45, CHE 89

Investigating the oxidation process of the Pt₃Ti(111) alloy surface on the atomic scale — •Marco Moors^1,2, Maria Buchholz^2,3, Séverine Le Moal^2,4, Klaus Wandelt^2,5, and Rainer Waser¹ — ¹Forschungszentrum Jülich — ²Universität Bonn — ³Karlsruher Institut für Technologie — ⁴Université Paris Sud — ⁵University of Wroclaw

The oxidation of reactive bimetallic alloys like the Pt₃Ti(111) surface is a promising approach to grow atomically thin titanium oxide films with a high degree of surface order on a metallic conducting substrate. Depending on the used preparation conditions several ordered oxide phases with both rectangular and hexagonal symmetry have been observed. The morphology of these phases is dominated by the surface strain caused by the interplay of the hexagonal substrate symmetry and the favoured rectangular oxide symmetry.

In this presentation the focus is set on the investigation of the first steps of the complex oxidation process on the atomic scale. At low oxygen pressures a titanium oxide phase with a characteristic zigzag structure is formed by a temperature induced segregation process of titanium atoms from the bulk to the outermost surface layer. By variation of the oxygen dosage and temperature the oxide coverage can be controlled ranging from small single islands up to the complete coverage of the entire surface. Due to the surface strain in all cases a regular arrangement of surface defects along the trenches between the zigzag lines can be observed, which may be important for the catalytic activity as well as for self assembly processes.