Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 26: Oxide und Isolatoren I
O 26.7: Vortrag
Samstag, 5. März 2005, 16:30–16:45, TU EB202
In-situ investigations of Ga2O3 stability on the CoGa(100) surface — •Alina Vlad1, A. Stierle1, I. Costina1, P. Nolte1, M. Delheusy1, H. Dosch1, E. Lundgren2 und J. Andersen2 — 1Max-Planck Institut für Metallforschung, Heisenbergstraße 1, 70569 Stuttgart — 2Department of Synchrotron Radiation Research, Institute of Physics, University of Lund, Box 118, SE-221 00 Lund, Sweden
The oxidation behavior of metallic alloy surfaces is of interest for fundamental studies, as well as for numerous applications in a variety of different fields such as heterogeneous catalysis, high temperature resistant coatings, microelectronics and gas sensors. As an example, the stability diagram of gallium oxide on CoGa(100) surface was determined. Surface X-ray Diffraction and High Resolution Core Level Spectroscopy experiments were performed at different temperatures in an oxygen partial pressure range up to 1 bar, following under which conditions the surface oxide starts to transforms into a bulk oxide. It was observed that at T < 350oC, the formation of the bulk oxide is kinetically hindered, the surface gallium oxide layer being stable even at 1 bar oxygen. Oxidation at 650oC and 2 · 10−2 mbar oxygen leads to the formation of a smooth and well-ordered epitaxial bulk Ga2O3, whereas at temperatures higher than 750oC the formation of the bulk oxide is accompanied by substrate faceting.