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O: Fachverband Oberflächenphysik

O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)

O 60.125: Poster

Wednesday, March 16, 2011, 17:30–21:00, P4

Nucleation, growth and thermal behaviour of Au and Cu-clusters on ZnO — •Dietmar Rother, Martin Kroll, and Ulrich Köhler — Institut für Experimentalphysik IV / AG Oberflächenphysik, Ruhr-Universität Bochum

The growth of Au and Cu on ZnO(1010) single crystal surfaces was studied as a first step to understand complex catalytically active systems, often consisting of small metal clusters on metal oxide surfaces. Thermal evolution of Au and Cu clusters on ZnO(1010) was studied in-situ with STM at elevated temperature. Au and Cu were deposited using MBE sources at room temperature. On the mixed terminated ZnO(1010) surface separated Cu clusters are formed at room temperature. A partial entrenching of Cu into the ZnO substrate at elevated temperature of T > 670K was found and points to a reaction of the Cu-clusters with the ZnO support. Au on ZnO shows a different behaviour: Annealing RT-deposited Au-clusters to comparable temperatures shows no reaction of Au-Clusters with the ZnO-substrate. After the initial coarsening, Au on ZnO shows no changes while scanning in-situ at elevated temperature up to 770K on a time scale of hours. The minimum cluster density is already reached at 420K. The behaviour on ZnO(1010) is compared to other ZnO surfaces and to TiO₂(110).