Regensburg 2013 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
O: Fachverband Oberflächenphysik
O 35: Poster Session I (Metal, semiconductor and oxide substrates: structure and adsorbates; Graphene)
O 35.66: Poster
Tuesday, March 12, 2013, 18:15–21:45, Poster B1
Surface structure of crystalline Ce7O12 films on Si(111) studied by LEED and XPS — •Olga Schuckmann1, Henrik Wilkens1, Robert Oelke1, Marvin H. Zoellner2, Andreas Schaefer3, Thomas Schroeder2, Marcus Bäumer3, and Joachim Wollschläger1 — 1Fachbereich Physik, Universität Osnabrück, Germany — 2IHP Frankfurt (Oder), Germany — 3Institute for Applied and Physical Chemistry, University of Bremen, Germany
Cerium oxide is a particularly interesting material for various applications in the field of catalysis due to its high oxygen mobility and storage capability.
Hence, the knowledge of the surface structure and oxygen vacancy formation is necessary to understand the elementary catalytic processes as well as the ionic conductivity.
Stoichiometric and structural changes induced by reducing epitaxial cub-CeO2(111) films grown on Si(111) was studied using low energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS).
The composition was determined by means of factor analysis of the Ce 3d X-ray photoemission spectra.
The results indicate that Ce4+ cations are reduced to Ce3+ by heating the
cerium dioxide films in ultrahigh vacuum.
At an annealing temperature of 1070 K a transition from a (1x1) CeO2 surface to a (√7x√7)R19.1∘ superstructure takes place. The analysis of the XP spectra reveals a ratio of 57% of Ce3+ and thus a stoichiometry of Ce7O12 for the reconstructed surface.