Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 15: Postersitzung (Adsorption an Oberfl
ächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Rastersondentechniken, Zeitaufgelöste Spektroskopie, Methoden)

O 15.45: Poster

Freitag, 4. März 2005, 17:00–20:00, Poster TU D

Surface Structures and Atomic Details of CeO₂(111) revealed by Dynamic Force Microscopy — •S. Gritschneder¹, Y. Namai², Y. Iwasawa², and M. Reichling¹ — ¹Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49076 Osnabrück, Germany — ²Department of Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

Ceriumdioxide is a catalytically active material with unique properties that allow it to store and release oxygen. It is highly interesting to analyse this catalytic surface on the atomic level to gain an in-depth understanding of the involved chemical processes and help to establish structure-function relationships for catalysis. In this contribution we present highly resolved images and atomic details of surface features on CeO₂(111) like terrace structures, step edges, kinks and hexagonally shaped pits that are naturally formed during surface preparation by sputtering and annealing cycles. We find that such structures can well be imaged with atomic resolution and exhibit a morphological characteristics that is in details significantly different from that of cleaved CaF₂(111), a surface with exactly the same crystallographic structure and a very similar lattice constant and ionic radii. We demonstrate that the non-contact, constant-height mode is the preferable mode of operation for dynamic force microscopy imaging at room temperature as it allows maximum resolution and undesired regulation artefacts can be minimized by carefully choosing scanning parameters, like detuning, scanning speed, and the gain of the distance regulation loop.