Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 18: Semiconductor Substrates: Structure, Epitaxy and Growth
O 18.5: Talk
Monday, March 20, 2017, 17:00–17:15, WIL C307
The structure of single-crystalline ZnO surfaces — •Jens Niederhausen1,2, Antoni Franco-Cañellas3, Simon Erker4, Martin Oehzelt2, Thorsten Schultz1, Patrick Amsalem1, Pardeep K. Thakur5, Katharina Broch6, David Duncan5, Anton Zykov1, Stefan Kowarik1, Tien-Lin Lee5, Alexander Gerlach3, Oliver T. Hofmann4, Frank Schreiber3, and Norbert Koch1,2 — 1Institut für Physik, Humboldt-Universität, Berlin, Germany — 2Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany — 3Institut für Angewandte Physik, Universität Tübingen, Tübingen, Germany — 4Institut für Festkörperphysik, TU Graz, Graz, Austria — 5Diamond Light Source, Oxfordshire, UK — 6Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
The electronic and catalytic properties of metal oxide surfaces are controlled by their atomistic details. For ZnO, ab-initio calculations predict rich phase diagrams, with the resulting structures varying significantly in terms of surface reconstruction, adsorbate species, and surface relaxation. A clear experimental identification of a predicted surface structure as well as the identification of thus far disregarded chemical species and structural effects arising from the surface preparation procedure are significantly assisted by the X-ray standing waves (XSW) technique that yields structural information with chemical sensitivity. We employed XSW to monitor how Ar+ sputtering deteriorates the surface crystallinity and show that this effect can be largely reversed by annealing. By variation of temperature and H2O partial pressure we determined surface structures for selected phase diagram points.