It has been pointed out to the authors that there is at ypographical error in the theoretical part of the experimental section of the original Communication. Specifically, the metal supercell used in the theoretical calculations was 5 ” 5i nstead of the published 4 ” 4. The resulting simulation cell was thus a4” 4(bi-)layer of ZnO on 2 layers of 5 ” 5C u(111). As also later pointed out by Bieniek et al. [1] this yields alattice mismatch between the two materials of only ca. 1% in order to strain the resulting ZnO overlayer structure as little as possible. The structures given in the abstract picture, Figure 3and the coordinates in the Supporting Information show the correct 4 ” 4ZnO @5” 5Custructure.

Scanning tunnelling microscopy (STM) and X-ray photoelectron spectroscopy (XPS, AES) were used to study MOCVD of Cu-clusters on the mixed terminated ZnO(1010) surface in comparison to MBE Cu-deposition. Both deposition methods result in the same Cu cluster morphology. After annealing to 670 K the amount of Cu visible above the oxide surface is found to decrease substantially, indicating a substantial diffusion of Cu atoms inside the ZnO-bulk. The spectroscopic data do not show any evidence for changes in the Cu oxidation state during thermal treatment up to 770 K.

The reaction of Cu‐clusters with a polar and a mixed terminated single crystalline ZnO‐substrate upon thermal treatment in UHV is studied in comparison with Au‐films. Scanning tunneling microcopy and spectroscopy in combination with photoemission experiments reveal the geometrical and chemical changes in the Cu‐cluster system on ZnO(0001)‐Zn and ZnO(10$\overline {1} $0) upon annealing up to 770 K. On ZnO($10\overline {1} 0$) the Cu‐clusters show a roof like outline with Cu(111) side facets. The data points to a Cu(110) interface with the ZnO‐substrate. The interface of the Cu‐clusters and the ZnO‐substrate was investigated by the controlled removal of clusters using STM‐tip manipulation exposing the “footprints” of the clusters. On both investigated ZnO surfaces an entrenching of the Cu‐clusters during annealing was found which partly explains the observed decrease of the amount of Cu visible above the ZnO‐substrate level upon annealing. Even at higher annealing temperature the main body of the cluster surface is still pure copper. No large scale oxidation or brass formation was found. Scanning tunneling spectroscopy shows an increased density of occupied states at the cluster perimeter which is possibly relevant as an active site in catalysis.

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Despite its enormous importance for heterogeneous catalysis, and in particular methanol synthesis, detailed information about the Cu/ZnO interface is still far from being complete. Here we present an overview of recent work carried out using different types of microscopical methods from which the complexity of the problem becomes apparent. In addition to results from transmission electron microscopy (TEM) and scanning electron microscopy (SEM) data also obtained using scanning probe techniques, in particular scanning tunneling microscopy (STM) and atomic force microscopy (AFM) are presented. Special attention is paid to the influence of elevated temperatures on the Cu/ZnO interface.