Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 15: Organic Electronics and Photovoltaics II (Joint Session with DS/CPP/O)
HL 15.1: Vortrag
Montag, 22. März 2010, 14:00–14:15, H8
Influence of the substrate-lattice-geometry on the island shape of organic thin films — •M. Benedetta Casu1, Britt-E. Schuster1, Indro Biswas1, Christoph Raisch1, Helder Marchetto2, Thomas Schmidt2, T. Onur Menteş3, Miguel A. Nino3, Andrea Locatelli3, and Thomas Chassé1 — 1IPTC, University of Tübingen, Tübingen, Germany — 2Fritz-Haber-Institut, Berlin, Germany — 3Sincrotrone Trieste S.C.p.A., Trieste, Italy
By using a combination of microscopic imaging and diffraction techniques with structural and chemical sensitivity, we studied the growth of diindenoperylene (DIP) on Au(100), and Au(111). Growth and structure of DIP films of different thickness were monitored in situ including real time PEEM and LEEM performed at the beamlines Nano-spectroscopy at Elettra, and UE49-PGM-b-SMART at BESSY. A layer-by-layer mechanism characterizes the initial growth in both cases followed by island nucleation, i.e., the growth follows the Stranski-Krastanov mode. The islands surprisingly show a fractal-like shape when the DIP thin films are deposited on a Au(111) single crystal. DIP thin films deposited on various substrates at RT have been investigated, revealing the tendency to Stranski-Krastanov growth but the observed islands were always compact (i.e. non-fractal). In particular, real time LEEM investigations on Au(100), under the same preparation conditions as on Au(111), show compact islands. We interpret the fractal growth of DIP for these kinetic growth conditions as a consequence of the triangular symmetry of the substrate, as seen in homoepitaxial and heteroepitaxial metal on metal growth.