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O: Fachverband Oberflächenphysik

O 79: Oxide Surfaces III

O 79.5: Vortrag

Donnerstag, 14. März 2013, 17:00–17:15, H45

Post deposition annealing of ceria *films on Si(111) — •Henrik Wilkens¹, Robert Oelke¹, Olga Schuckmann¹, Reinhard Olbrich¹, Marvin H. Zoellner², Thomas Schroeder², Michael Reichling¹, and Joachim Wollschläger¹ — ¹Fachbereich Physik, Universität Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany — ²IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany

A 250 nm cub-CeO₂(111) film grown on hex-Pr₂O₃/Si(111) is annealed under UHV conditions. Atomic force microscopy (AFM) and spot profile low energy electron diffraction (SPA-LEED) were used to resolve the surface morphology. The chemical composition was studied by photoelectron spectroscopy (XPS). In addition, the changes of the bulk structure were probed by in-situ x-ray diffraction (XRD) measurements.
The surface exhibit triangular shaped facets as shown by AFM which vanish at higher temperatures. Moreover, several superstructures appear in the LEED pattern due to ordered oxygen vacancy formation. Also the XPS data shows that the surface reduces continuously at higher annealing temperatures.
The XRD measurements reveal that not the whole film is reduced since a diffraction signal of cub-CeO₂(111) is still visible at elevated temperatures. Furthermore, it is shown that above a critical temperature the hex-Pr(0001) buffer layer is destroyed and silicon diffuses into the ceria film.