Dresden 2009 – scientific programme

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O: Fachverband Oberflächenphysik

O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)

O 42.49: Poster

Wednesday, March 25, 2009, 17:45–20:30, P2

STM study of growth, structure, and stability of DMDS on Au(111) — •Patrick Mehring, Axel Beimborn, Daniel Weier, Frank Schönbohm, Tobias Lühr, and Carsten Westphal — Fakultät Physik - Technische Universität Dortmund, Otto-Hahn-Str. 4, D 44221 Dortmund, Germany

Systems of self-assembled monolayers (SAM) are in the focus of present research activities due to their potential applications in fields like molecular electronics, bio-sensing, and the manipulation of metallic surface characteristics. Therefore, monolayers of linear alkanethioles are considered as ideal model systems. In this study the growth, structure, and stability of Dimethyldisulfide (DMDS) layers on Au(111) was investigated by scanning tunneling microscopy. SAMs were formed by solution deposition methods at room temperature. We varied the deposition time from 6h to 24h. Subsequently, several thermal annealing steps with increasing temperatures were performed in vacuum. After each step, the monolayer was investigated by STM. A stripe phase with increasing coverage as a function of the deposition time was observed. After annealing at 80°C molecular islands were observed at the surface. After island formation the stripe phase is removed completely due to the rearrangement of molecules at the surface. Between the islands an amorphous phase was found. Increasing the temperature to 150°C leads to a disappearance of the islands. The herringbone reconstruction of the gold surface reappeared.