Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 37: Posters: Plasmonics, Electronic Structure and Spin-Orbit Interaction, Semiconductor and Insulator Surfaces, Nanostructures

O 37.68: Poster

Dienstag, 1. April 2014, 18:30–22:00, P2

SPA-LEED studies on structure and morphology of Ce_xPr_1−xO₂ films — •Wanja Spiess¹, Henrik Wilkens¹, Marvin H. Zoellner², Gang Niu², Thomas Schroeder^2,3, and Joachim Wollschläger¹ — ¹Fachbereich Physik, Universität Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany — ²IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany — ³BTU Cottbus, Institute of Physics, Konrad-Zuse-Str.1, 03046 Cottbus, Germany

Rare earth oxides (REOs) are in the focus of research for several catalytic applications, e.g. the three-way automotive exhaust catalysis. Lattice oxygen directly participates in these surface redox reactions based on the Mars-van-Krevelen mechanism. Therefore, the structural properties of the REOs and especially oxygen vacancies have a strong impact on the catalytic reactivity and selectivity. In addition, the intermixing of different REOs gives further opportunity of tuning the catalytic properties. We present a post deposition annealing study of mixed Ce_xPr_1−xO₂ films grown on Si(111) using SPA-LEED (spot profile analysis at low energy electron diffraction) to control structural properties. Several crystalline structures are stabilized at moderate temperatures while at high temperatures silicide is formed. Spot profile analysis of the fundamental diffraction spot reveals a strong correlation between surface morphology (atomic steps) and the stoichiometry of the films.