Berlin 2008 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 5: Scanning and diffraction methods

DF 5.6: Vortrag

Montag, 25. Februar 2008, 16:30–16:50, EB 407

Atomic scale evidence for faceting stabilization of a polar oxide — •Frank Ostendorf, Stefan Torbrügge, and Michael Reichling — Fachbereich Physik, Universität Osnabrück, Barabarastr. 7, 49090 Osnabrück

Polar metal oxide surfaces are of highest importance for various applications like catalysis, sensor technology and optoelectronic devices. In matters of industrial applications and merit these surfaces represent a research field of general scientific interest. With this study we corroborate new aspects in the basic understanding of one of the most prominent polar surfaces, namely zinc oxide (ZnO). With respect to nano-electronic devices the surface properties of zinc oxide and zinc oxide compounds are of greatest importance. By highest resolution dynamic scanning force microscopy (SFM) operated in the non-contact mode (NC-AFM), we reveal the complex stabilization mechanism of polar zinc terminated ZnO(0001). The nanoscopic and atomic structures unveiled corroborate a model of stabilization via triangular structures. High temperature preparation (T > 1300 K) yields a novel phase with an additional stabilization by faceting in the form of highly ordered step arrays. The terraces between steps are partly covered with triangular reconstructions exhibiting exclusively {1010} nano-facets on step edges. The combination of both mechanisms allow a complete stabilization of the surface without involvement of adsorbates.