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O: Fachverband Oberflächenphysik
O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)
O 60.33: Poster
Mittwoch, 16. März 2011, 17:30–21:00, P4
Growth mode, morphology, and reducibility of CeO2(111) thin films on Cu(111) — Filip Dvořák1, Oleksandr Stetsovych1, Michael Steger2, El Miloudi Cherradi2, Iva Matolínová1, Natalya Tsud1, Michal Škoda1, Tomáš Skála3, •Josef Mysliveček1, and Vladimír Matolín1 — 1Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, Praha 8, Czech Republic — 2Heinrich-Heine-Universität, Institut für Experimentelle Physik der kondensierten Materie, Universitätsstrasse 1, Düsseldorf, Germany — 3Sincrotrone Trieste SCpA, Strada Statale 14, km 163.5, Basovizza-Trieste, Italy
We investigate morphology and degree of reduction in model oxide system CeO2 (ceria) on Cu(111) using scanning tunneling microscopy and photoelectron spectroscopy. We identify growth mechanisms of ceria on Cu(111) - formation of incomplete oxide interfacial layer and formation of three-dimensional ceria pyramids by stacking of monolayer-high islands. Using these mechanisms we control the coverage, the number of open monolayers, and the step density of ceria thin films on Cu(111). Annealing in vacuum allows us to control besides the morphology also the degree of ceria surface reduction. We find a correlation between surface reduction and morphological stability in annealed ceria layers. Oriented and stoichiometric thin films of ceria on Cu(111) can be prepared at temperatures as low as 150 ∘C and 250 ∘C. Both the morphology and the degree of reduction of these films readily change with increasing temperature, which must be accounted for in evaluating temprature-programmed experiments with ceria on Cu(111).