Regensburg 2007 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 25: Symposium: Real Time Growth Studies III
DS 25.3: Vortrag
Donnerstag, 29. März 2007, 16:00–16:15, H32
Real-Time Observation of Organic Growth on metals - a SMART Investigation — •Pierre Levesque1, Helder Marchetto1, Ullrich Groh2, Florian Maier2, Thomas Schmidt2, Rainer Fink3, Tomáš Skála1, Eberhard Umbach2, and Hajo Freund1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany — 2Universität Würzburg, Experimentelle Physik II, 97074 Würzburg, Germany — 3Universität Erlangen-Nürnberg, Physikalische Chemie II, 91058 Erlangen, Germany
The growth of two similar molecules - PTCDA and NTCDA - on Ag(111) and Au(111) surfaces has been studied in situ by the SMART, using PEEM with UV-light and polarized monoenergetic synchrotron radiation and LEEM. Above room temperature both systems grow in the Stranski-Krastanov mode: first two closed layers of molecules are formed, followed by three dimensional (3D) growths of islands. Strong differences are observed in the molecular orientations: whereas the PTCDA molecules are always flat-lying on the substrate, the NTCDA behaves differently: the molecules are also flat-lying in the double layer but tilted by about 45° in the islands. We report on surprising observations like reduced sticking coefficient, metastable layers, internal crystal structures, and dynamic changes within the layers. Differences in the growth and the temperature dependence of the two systems are discussed. Contrast mechanisms leading to the presented results will also be addressed. Project funded by BMBF under contract no. 05 KS4WWB/4.