Berlin 2008 – scientific programme

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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 55.48: Poster

Wednesday, February 27, 2008, 18:30–19:30, Poster F

Study of formation and thermal stability of Fe layers on ZnO surfaces — Alexander Demund, Daniel Wett, Sylvia Reiche, Rüdiger Szargan, and •Reinhard Denecke — Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, 04103 Leipzig

Formation and thermal stability of Fe layers on ZnO surfaces have been studied by means of X-ray Photoelectron Spectroscopy and Low Energy Electron Diffraction. Experiments were performed on the polar surfaces ZnO(0001) and ZnO(000-1) and on the non-polar (1120) surface. The results indicated a pseudo 2D growth mode for iron on ZnO at room temperature, which was less pronounced on the Zn-terminated (0001) surface. Under ultra high vacuum conditions low coverages of deposited Fe⁰ on all ZnO single crystal surfaces were partially oxidized by a small fraction of residual -OH-groups and ZnO to FeO. A strong temperature dependence of the interface reactivity was found upon annealing. Starting from 200 - 300^∘C iron was first oxidized to bivalent iron oxide. After complete oxidation of Fe⁰ to Fe²⁺ at around 400^∘C, Fe²⁺ reacted to Fe³⁺. Above temperatures of 500^∘C the deposited metallic iron was completely oxidized to trivalent iron. Differences observed for the different surface orientations will be discussed.

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