Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 59: Metal Substrates I
O 59.13: Vortrag
Mittwoch, 2. April 2014, 19:00–19:15, WIL A317
Physisorbed molecular networks as surfactants for the growth of Ag on Ag(100) — •Claudius Morchutt2,3, Gustavo Ruano2,3, Klaus Kern1,2,3, and Magali Lingenfelder1,2,3 — 1Max Planck Institute for Solid State Research, D-70569 Stuttgart — 2Institut de Physique de la Matière Condensée, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne — 3Max Planck-EPFL Center for Molecular Nanoscience, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne
Homoepitaxial growth of Ag on Ag(100) proceeds by a quasi layer-by-layer fashion at room temperature (RT). This means that higher-layer islands nucleate before the completion of lower layers and it leads to kinetic roughening of the multilayer film. Previous studies have shown that deposition of metal atoms such as Sb can act as surfactants improving the smoothness of the films. However, these surfactants are difficult to remove from the surface after growth. Here we show by Scanning Tunneling Microscopy (STM) in ultra-high vacuum (UHV) that the growth mode of Ag on Ag(100) at RT is significantly modified by the presence of physisorbed molecular networks. The islands consisting of terephtalic acid (TPA, benzene-1,4-dicarboxylic acid) are stabilized via hydrogen bonds. Upon Ag deposition the Ag atoms penetrate the molecular islands without disrupting their supramolecular network that in turn enhances the coarsing of the Ag islands underneath. Furthermore, the organic molecules can easily be removed by post-annealing at moderate temperature.