IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Monday Sessions
       Session SS2-MoM

Paper SS2-MoM2
Nanostructed Growth of Metal Clusters on Ultrathin Al@sub 2@O@sub 3@ Films on Ni@sub 3@Al(111)

Monday, October 29, 2001, 10:00 am, Room 121

Session: Metal Clusters
Presenter: A. Rosenhahn, Lawrence Berkeley National Laboratory
Authors: A. Rosenhahn, Lawrence Berkeley National Laboratory
A. Wiltner, Universitaet Bonn, Germany
K. von Bergmann, Universitaet Hamburg, Germany
J. Schneider, Lawrence Berkeley National Laboratory
C. Becker, Universitaet Bonn, Germany
B.S. Mun, Lawrence Berkeley National Laboratory
F.J.G. de Abajo, Centro Mixto CSIC-UPV/EHU
M.A. van Hove, Lawrence Berkeley National Laboratory
C.S. Fadley, Lawrence Berkeley National Laboratory
K. Wandelt, Universitaet Bonn, Germany
Correspondent: Click to Email
Highly ordered, ultrathin alumina films can be grown on Ni@sub 3@Al(111) by simply exposing the alloy surface to oxygen at high temperatures.@footnote 1@ Because of the conductibility of the thin films, the properties of metal aggregates on the surface of these oxide films can easily be studied without charging of the surface. Using STM, we have investigated the nucleation properties of different types of metals reaching from very noble ones like Ag, Au, and Cu to metals which are more reactive towards oxygen like V and Mn. All clusters show preferred nucleation on distinct sites of the oxide film.@footnote 2@ As long as the oxide is not entirely covered by metal, two different mean cluster distances of 2.5 nm and 4.6 nm can be found. The distribution of the clusters on the surface reveals a hexagonal symmetry. The same periodicity can be found on the metal-free oxide film, depending on the applied bias voltage.@footnote 3@ As these superstructures reveal the same symmetry and periodicity as the cluster distribution, the nucleation is clearly determined by these sites. Because the superstructures are just at certain bias voltages visible, the prefered nucleation is not simply due to a modulation of the morphology. We will discuss, in which way the structure of the oxide film and the nucleation of the metal clusters are correlated. @FootnoteText@ @footnote 1@ A. Rosenhahn, J. Schneider, C. Becker, and K. Wandelt, J. Vac. Sci. Technol. A 18(4), 1923 (2000). @footnote 2@ C. Becker, K. v. Bergmann, A. Rosenhahn, J. Schneider, K. Wandelt, Surf. Sci. Lett., in Press. @footnote 3@ A. Rosenhahn, J. Schneider, J. Kandler, C. Becker, and K. Wandelt, Surf. Sci. 433-435, 705 (1999).