Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 20: Organische Dünnschichten II
O 20.6: Vortrag
Samstag, 5. März 2005, 12:00–12:15, TU EB202
In-Situ study of the first stages of F16CuPc growth on SiO2 — •Dimas Garcia de Oteyza 1, Esther Barrena1, Oriol Ossó2, Stefan Sellner1, and Helmut Dosch1,3 — 1Max Planck Institut für Metallforschung, Stuttgart — 2Institut de Ciència de Materials de Barcelona, CSIC — 3Institut für Theoretische und Angewandte Physik, Universität Stuttgart
We have studied the first stages of F16CuPc growth on SiO2 by AFM and in-situ X-ray measurements. For thicker films they form a well ordered layered structure, with layers of virtually upright standing molecules and a spacing of 14.3 Å. At low coverage, both techniques coincide in the observation of striking structural changes on the first layers. The layer heights found for the first, second and third layers are 12.5 Å, 15 Å and 21 Å respectively. Besides, both the size and the aspect ratio of the elongated crystallites increase in the subsequent layers. From the X-ray data an additional layer at the interface with the SiO2 is obtained. This layer has a saturation thickness of around 6.5 Å and it shows a periodicity in the surface plane of 15 Å, which corresponds to the molecular size along one of its sides. The electronic density of this interfacial layer is about half of the electronic density of the thicker films. The growth behaviour of the first 3 layers has been characterized by both techniques. AFM and in-situ X-ray diffraction show a very good agreement.