Berlin 2008 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 18: Poster: Towards Molecular Spintronics, Organic Thin Films, Optical Layers, Vibrational Spectroscopy, Tayloring organic interfaces
DS 18.26: Poster
Dienstag, 26. Februar 2008, 14:30–19:30, Poster A
Structural, Morphological, and Optical Properties of Tetraphenylporphyrin Films on Silicon Substrates — •Simona Pop1, Tobat Saragi2, Sylvia Wenmackers3, Josef Salbeck2, Patrick Wagner3, and Norbert Esser1 — 1ISAS-Institute for Analytical Sciences, Department Berlin, Albert-Einstein Str. 9, D-12489, Berlin, Germany — 2Macromolecular Chemistry and Molecular Materials (mmCmm), Department of Science and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett Strasse 40, D-34109 Kassel, Germany — 3Hasselt University, Institute for Materials Research, Wetenschapspark 1, 3590 Diepenbeek, Belgium
Thin films of free base-meso-tetraphenylporphyrin (H2TPP) grown by organic molecular beam deposition on silicon substrates are characterized by means of spectroscopic ellipsometry, scanning electron microscopy, and atomic force microscopy techniques. The anisotropic dielectric function of H2TPP films is determined in the photon energy range from 0.73 to 5 eV. The imaginary part of the dielectric function exhibits the typical Q and Soret bands. The Q band (pi-pi* transition) displays the typical vibrational structure consisting of the following subbands Qx(0,0) at 1.90 eV, Qx(1,0) at 2.08 eV, Qy(0,0) at 2.2 eV, and Qy(1,0) at 2.38 eV. It is observed only for the in-plane component of the dielectric function meaning that most of the H2TPP molecules adopt a planar orientation with respect to the substrate surface. The thickness dependence of the dielectric function of the H2TPP films is additionally discussed.