Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 31: Organische Dünnschichten III
O 31.7: Vortrag
Montag, 7. März 2005, 12:15–12:30, TU EB420
Molecular resolution in non-contact atomic force microscopy: Experiments and force field calculations — •Tobias Kunstmann1, Regina Hoffmann2, Markus Fendrich1, and Rolf Möller1 — 1Universität Duisburg-Essen, D-45141 Essen, Germany — 2Universität Karlsruhe, D-76128 Karlsruhe, Germany
A scanning force microscope operated in the dynamic force mode has been used to analyze the arrangement of 3,4,9,10-perylenetetracarboxylic-dianhydride (PTCDA) molecules on a KBr surface. The molecules do not form a close-packed layer but crystallites with the shape of truncated pyramids. Even after depositing only 0.3 molecular layers of PTCDA, these crystallites have a height of 20-30 molecular layers. We have been able to resolve individual molecules of the top layer and on some of the crystallite’s facets. Additionally, molecular force field calculations simulating a silicon tip on a layer of α-PTCDA(102) have been performed. For the frequency shift, we used the formula given by Garcia et al.[1]. The results agree well with the experimental data.
This work was funded by the SFB616 "Energy dissipation at surfaces" of the Deutsche Forschungsgemeinschaft.
[1] Ricardo García, Rubén Pérez, Surf. Sci. Rep. 47 (2002), 197