AVS 45th International Symposium
    Surface Science Division Thursday Sessions
       Session SS-ThP

Paper SS-ThP34
AES-LEED Study of the Growth Mode of Ag on Au (111),(311) and (554) Single Crystal Surfaces

Thursday, November 5, 1998, 5:30 pm, Room Hall A

Session: Surface Science Division Poster Session
Presenter: F.A.B. Reniers, Universite Libre de Bruxelles, Belgium
Authors: V.F.S. Rooryck, Universite Libre de Bruxelles, Belgium
C. Buess-Herman, Universite Libre de Bruxelles, Belgium
G.A. Attard, University of Wales, United Kingdom
F.A.B. Reniers, Universite Libre de Bruxelles, Belgium
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The growth mode of silver onto gold substrates has been the subject of many controversies. The energetics and lattice misfit between gold and silver seems to favor a layer-by-layer mode, confirmed by some studies, while others reported a Stransky-Krastanov mode. The deposition method (electrodeposition, UHV deposition), the analysis technique and the surface structure could be responsible for these different results. We have undertaken a LEED-AES study of the deposition of thermally evaporated silver onto gold single crystal surfaces. The Au (111), (311) and (554), with different atomic roughness were investigated. The deposition mode was determined from the intensity versus time evolution of the Auger lines of gold (69 eV) and silver (351-356 eV). The Gallon model was used to fit the experimental data to theoretical simulations. The most recent values of IMFP and AL were introduced in the model. Following the results, the Stransky-Krastanov growth occurs, but 2 or 3 layers are deposited before the island growth begins. The evolution of the surface structure during silver deposition was simultaneously followed by LEED. We showed that the reconstruction of thermodynamically equilibrated pure gold surfaces was progressively removed by silver adsorption, apparently starting at half a monolayer coverage. The possibility of the formation of an interfacial alloy is investigated, and a comparison is made with the results that we obtained for the electrodeposition of silver on the same gold surfaces.