Berlin 2008 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 17: Poster: Trends in Ion Beam Technology, Magnetism in Thin Films, Functional Oxides, High-k Dielectric Materials, Semiconductor Nanophotonics, Nanoengineered Thin Films, Layer Deposition Processes, Layer Growth, Layer Properties, Thin Film Characterisation, Metal and Amorphous Layers, Application of Thin Films

DS 17.13: Poster

Dienstag, 26. Februar 2008, 09:30–13:30, Poster A

Chemical composition of annealed Fe/SrTiO₃(001) and FeO/SrTiO₃(001) interfaces — •Alexander Demund, Benjamin Heinrich, Rüdiger Szargan, and Reinhard Denecke — Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstrasse 2, 04103 Leipzig

Physical interface properties, such as electron and ion conductivity, are strongly tied to the chemical composition of the interfaces. In order to understand processes during deposition or annealing, such as displacement and chemical reactions of atoms in the vicinity of the interface, we have chosen to investigate Fe/SrTiO₃(001) and FeO/SrTiO₃(001) interfaces by means of chemical state sensitive X-ray photoelectron spectroscopy.

During deposition of Fe in ultra high vacuum at room temperature oxidation of iron and reduction of titanium occurred. Annealing of iron and iron(II) oxide on SrTiO₃ caused an inversion of the reaction tendency observed during deposition: iron oxide was in general reduced, while reduced titanium was oxidized. As annealing of SrTiO₃ leads to an increasing number of defects, such as oxygen vacancies or Ti(III)-oxygen complexes, we used two differently pre-annealed SrTiO₃ crystals (600^∘C and 800^∘C). Thermally activated interface reactions occurred at lower temperatures for the crystal pre-annealed at 800^∘C. On this sample, the number of additional crystal defects detected during annealing was particularly elevated. The increased ion conductivity may play a decisive role in the reactivity of the interfaces.

Work has been supported by DFG (FG 404 Sz58/15).