Regensburg 2000 – scientific programme

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O: Oberflächenphysik

O 11: Postersession (Eröffnung)

O 11.102: Poster

Monday, March 27, 2000, 19:00–22:00, Bereich C

Dynamic study of CuPt surface alloy by Auger electron spectroscopy — •J.S. Tsay, T. Mangen, R.-J. Linden, and K. Wandelt — Institut für Physikalische und Theoretische Chemie der Universität Bonn, Wegelerstr. 12, D-53115 Bonn

Under certain conditions, the kinetics of the dissolution of a thin film into a crystal may be blocked near the surface and causes formation of a surface alloy. Since the adatoms can only diffuse into the topmost few layers, Fick*s approxiation can not fit the experimental data well. A method of determining the energy barrier of diffusion for surface atoms is introduced from a dynamic study of a surface alloy by Auger electron spectroscopy. The corresponding energy barrier is 1.11+0.12 eV obtained from data consistent with result of Monte Carlo simulation for one monolayer Cu/Pt(111) film. The composition of the annealed Cu ultrathin film was determined to be CuPt by a combination of argon sputtering and Auger electron spectroscopy. The change in valence band during alloy formation is discussed.