Berlin 2008 – scientific programme

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O: Fachverband Oberflächenphysik

O 18: Poster Session I - MA 141/144 (Atomic Wires; Size-Selected Clusters; Nanostructures; Metal Substrates: Clean Surfaces+Adsorption of Organic / Bio Molecules+Solid-Liquid Interfaces+Adsorption of O and/or H; Surface or Interface Magnetism; Oxides and Insulators: Clean Surfaces)

O 18.24: Poster

Monday, February 25, 2008, 18:30–19:30, Poster F

Characterization of FDT molecules and its binding properties on metallic surfaces — •Jedrzej Schmeidel, Gernot Gardinowski, Christoph Tegenkamp, and Herbert Pfnür — Institut für Festkörperphysik, Universität Hannover, Abteilung Oberflächen, Appelstrasse 2, 30167 Hannover, Germany

Recently performed VASP calculations concerning the adsorption of ferrocene-1,1’-dithiol (FDT) molecules on perfect and defective Ag(111) surfaces show that details of the chemical bond have a large influence on the DOS near Fermi energy, i.e the transport behavior. Furthermore, at defect sites the thiolate bonded FDT is energetically favored. We have experimentally investigated FDT on metallic surfaces, to gain insight into this subject. FDT molecule was chosen due to its large conductance and a high structural flexibility with respect to rotation of the two cyclopentadienyl (Cp) rings. As substrate Au(111) and epitaxially grown Ag/Si(111) were used. On both surfaces the adsorption process and the stoichiometry of the FDT was controlled and checked by XPS/UPS. On Au surfaces, self assembled monolayer (SAM) structures have been investigated by means of STM, where assembled structures have been partly seen in form of parallel oriented lines with average spacings of 1.7nm. Submonolayer coverages, generated by thermal evaporation, have been investigated on Ag √3×√3/Si(111). First results about the preferred adsorption at characteristic defect sites (grain boundaries, steps) will be presented and their electronic structure, obtained by STS, correlated with theoretical results.