Helder Marchetto1, Thomas Schmidt2, Ulrich Groh2, Rainer Fink3, Eberhard Umbach2 and the SMART collaboration
1 Fritz-Haber-Institut der Max-Planck Gesellschaft, D-14195 Berlin, Germany
2 Experimentelle Physik II, Universität Würzburg, D-97074 Würzburg, Germany
3 Physikalische Chemie II, Universität Erlangen, D-91058 Erlangen, Germany
By Hg-excited photo-emission electron microscopy (PEEM) and low energy electron microscopy (LEEM) we investigated the microscopic growth behaviour of organic thin films using 3,4,9,10-perylene-tetracarboxylicacid dianhydride (PTCDA) on a Ag(111) and Au(111) single crystal substrates as an example. Direct, real-time observation allows us to correlate the initial growth modes and the related kinetic parameters with substrate properties like terrace width, step density, and step bunches from the submonolayer range up to five layers or more . On the Ag(111) surface the growth mode transition from quasi layer-by-layer to Stranki-Krastanov occurs at about 350 K. This transition is associated with the presence of metastable layers during and after growth . The systematic observation of the different decay modes for metastable layers and the instauration of steady-states between the metastable layers and 3-dim islands are discussed and correlated to the growth mode transition.
Further evidence of the influence of the substrate morphology on the growth mode is given for the Au(111) surface where we observe simultaneously a Stranski-Krastanov and a layer-by-layer growth, depending on the local step density of the substrate.
 H. Marchetto, U. Groh, Th. Schmidt, R. Fink, H.-J. Freund and E. Umbach, Chemical Physics 325 (2006) 178-184.
 H. Marchetto, Th. Schmidt, U. Groh, R. Fink, H.-J. Freund and E. Umbach, in preparation.
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