DPG Phi
Verhandlungen
Verhandlungen
DPG

Regensburg 2010 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

O: Fachverband Oberflächenphysik

O 71: Metal substrates: Epitaxy and growth

O 71.1: Talk

Thursday, March 25, 2010, 15:00–15:15, H31

Interaction of gold with clean and oxygen-covered Re(1010) surfacesSebastian Schwede, •Susanne Schubert, Christian Pauls, and Klaus Christmann — Freie Universität Berlin, Takustr. 3, 14195 Berlin

The structure, growth and morphology of thin Au films deposited on both clean and oxygen-covered rhenium (1010) surfaces has been studied as a function of coverage Θ and temperature T using LEED, STM and thermal desorption spectroscopy (TDS). In the absence of oxygen, Au forms a variety of ordered (1× n) phases (n = 3, 4, 5, 6 and 1) with the Au adsorption energy increasing from ∼320 kJ/mol at low Θ to ∼380 kJ/mol near the bilayer (1×1) structure (Θ=2), where the heat of sublimation of bulk Au, Δ Hsub, is reached. Au wets the Re surface completely, for Θ>2, a simultaneous multilayer growth is observed. On the oxygen covered Re surface with its well-known (reconstructed) (1×3)-2O phase (Θ= 2/3), however, Au deposition at 300 K causes immediate 3D clustering with rough and heterogeneous films pointing to a clear non-wetting behavior. Annealing of these films at 850 K gives the Au atoms sufficient mobility to coalesce to cylindrically shaped aggregates of ca. 50 Å diameter and 100 Å average length which are aligned parallel to the troughs of the Re surface. At elevated temperatures, Au desorbs first from the bulk phase (EdesHsub), only as oxygen desorption becomes competitive, Au atoms can diffuse to and interact with the bare Re sites and desorb with the characteristic energy.

100% | Mobile Layout | Deutsche Version | Contact/Imprint/Privacy
DPG-Physik > DPG-Verhandlungen > 2010 > Regensburg