Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 14: Poster session I (Adsorption, Epitaxy and growth, Phase transitions, Surface reactions, Organic films, Electronic structure, Methods) (sponsored by Omicron Nanotechnology GmbH)
O 14.44: Poster
Montag, 27. März 2006, 18:00–21:00, P2
Thickness dependent NEXAFS study of pentacene/Ag(111) — •S.K.M. Jönsson1, B. Doyle2, M. Pedio2, S. Nannarone2, and F.S. Tautz1 — 1School of Engineering and Science, International University of Bremen, P.O. Box 750561, 28725 Bremen, Germany — 2TASC-INFM National Laboratory, Area Science Park, 34012 Basovizza (Trieste), Italy
The thickness dependent orientation and the in-plane order/disorder of pentacene layers on Ag(111) substrates has been investigated with Near-Edge X-ray Absorption Spectroscopy (NEXAFS). Based on previous XPS, STM and HREELS studies, it is known that for RT deposition the first monolayer is a disordered layer in which the pentacene molecules are oriented parallel to the Ag surface. With additional pentacene growth, an ordered layer is formed on top of the first disordered layer. This ordered growth is continued for a few additional layers. The NEXAFS signals, taken at 5 different polar angles for each of the layers, allows us to determine the orientation of the pentacene molecules in each of the layers formed, while the NEXAFS signals taken at 5 different azimuthal (in-plane) angles provides qualitative information concerning the degree of order/disorder within a layer. By comparing the NEXAFS signal of the monolayer, bilayer, etc with the NEXAFS signal of thick pentacene film it is also possible to draw conclusions concerning the bonding of each of the layers.