[Zurück]

C. Eisenmenger-Sittner, E. Klein, B. Schwarz, C. Tomastik, F. Misjak:
"MECHANISMS OF SOLID STATE SURFACE WETTING OF TIN (Sn) ON ALUMINIUM (Al) UNDER UHV CONDITIONS";
Vortrag: International Vacuum Congress 16, IVC-16, Venedig, Italien; 28.06.2004 - 02.07.2004.

Under Ultra High Vacuum (UHV) conditions Tin (Sn) tends to form a monoatomic wetting layer on Aluminium (Al) surfaces if Sn-islands which were formed by a deposition process exist on a bare Al-surface. These islands act as Sn-reservoirs and seem to emit Sn as long as a monolayer of Sn is formed on the surface. Experimentally this process was investigated in previous publications (Eisenmenger-Sittner at al., Surf. Sci. 489, 2001, 161-168). The over-all thermodynamic driving force is most probably the reduction of the surface energy of the bare Al-layer by the total coverage with Sn.
In this paper the mechanisms leading to wetting layer formation will be discussed in more detail by means of thermodynamic considerations and Kinetic Monte Carlo Simulations (KMC). Thermodynamics is employed to describe the lateral coverage of the free Al surface by mass emission from pre-existing aggregates (Sn-islands). The Surface energy of the bare surface is considered higher than the surface energy of the totally covered system. KMC, on the other hand, will be employed to describe the dynamics of the process and to understand the fact why the thickness of the wetting layer is limited to one monolayer.
This work is supported by the Austrian Science Fund (FWF) under grant Nr. P-15739. The financial support of the Hungarian National Science Foundation under contract No. OTKA T033075 and to EU under contract No. ICAI-CT-2000-70029 is acknowledged.