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O: Fachverband Oberflächenphysik

O 14: Metal Substrates: Epitaxy and Growth

O 14.13: Talk

Monday, March 26, 2007, 17:15–17:30, H39

Vanadium Oxide Superstructures and their Transitions on W(110) — •Benjamin Borkenhagen, Gerhard Lilienkamp, and Winfried Daum — Institut für Physik und Physikalische Technologien, TU Clausthal, Leibnizstr. 4, D-38678 Clausthal-Zellerfeld

Epitaxially grown ultrathin vanadium oxide films on a W(110) single crystal surface exhibit a wealth of superstructures, depending on growth conditions such as temperature and oxygen partial pressure. The thickness of the deposited vanadium oxide films was in the range from submonolayer to a few monolayers as determined by a quartz microbalance. The structure of the films and their composition was analysed by LEED and AES, respectively. The oxidation state of vanadium in the films was determined by AES. For atomically smooth films, low energy electron microscopy (LEEM) reveals flat terraces with widths up to 6 μm separated by monoatomic steps. Using dark-field imaging the domain structure of the films is resolved with high contrast. Depending on the preparation conditions (oxygen partial pressure, heating rate), a more granular or a more homogeneous domain structure is obtained. Structural transitions of the thin oxide films under oxidising or reducing conditions have been monitored by LEEM.