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MM: Fachverband Metall- und Materialphysik

MM 6: Diffusion and Point Defects II

MM 6.1: Vortrag

Montag, 22. März 2010, 11:30–11:45, H6

Study of ⁴⁴Ti grain boundary self diffusion in thin nanocrystalline TiO₂ films — •Petr Straumal^1,2, Ata Myatiev², Sergiy Divinski¹, and Gerhard Wilde¹ — ¹Institut für Materialphysik, Universität Münster, Wilhelm-Klemm-Str. 10, D-48149 Muenster, Germany — ²National University of Science and Technology "MISIS", Leninsky Prospect 4, 119049 Moscow, Russia

Titanium dioxide is known for its photo-catalytic properties and enhanced corrosion resistance in aqueous environments. For catalytic applications it is helpful to dope the TiO₂ with metal dopants which can move the absorption edge of TiO₂ from the UV to the blue region of the visible spectrum. Also the electrical conductivity of non-stoichiometric TiO2 is proportional to the concentration of oxygen vacancies. The grain boundary diffusion plays a significant role in both processes. Numerous works are dedicated to the diffusion of various dopants like niobium or chromium in TiO₂ but so far, none studied the self diffusion of titanium. The grain boundary self diffusion in thin nanocrystalline TiO₂ films is investigated. The oxide films are produced using a novel deposition method from metal-organic precursors at relatively low (400-500^∘C) temperatures. The diffusion was measured by means of the radiotracer technique applying the ⁴⁴Ti isotope and utilizing ion beam sputtering for sectioning. In addition, the microstructure was investigated using TEM. The results are discussed with respect of the relationship between grain boundary self diffusion and the synthesis pathway and resulting microstructure of the nanoscale functional oxide films. Support by DAAD is gratefully acknowledged.