Hamburg 2001 – wissenschaftliches Programm
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SYOF: Organische Festkörper
SYOF 5: Poster Session
SYOF 5.30: Poster
Dienstag, 27. März 2001, 17:00–19:00, Aula S3
Optical anisotropy in epitaxial organic thin films — •J. O. Ossó1,2, M. Garriga1, M. I. Alonso1, F. Cerdeira1,3, V. Kruppa2, F. Schreiber2,4, and H. Dosch2,4 — 1Institut de Ciència de Materials de Barcelona, CSIC, E-08193 Bellaterra, Spain — 2Max-Planck-Institut für Metallforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany — 3Instituto de Física, Univ. Estadual de Campinas, UNICAMP, Campinas S.P., Brazil — 4Institut für Theoretische und Angewandte Physik, Universität Stuttgart, D-70550 Stuttgart, Germany
We present a study of the correlation between structural and optical anisotropy in perfluorinated copper phthalocyanines (F16CuPc), grown by organic molecular beam deposition in UHV on a substrate with two-fold symmetry (A-plane sapphire). Measurements of Raman scattering and spectroscopic ellipsometry reveal strong anisotropy in the optical properties of the film as the sample is rotated about the surface normal. These results show evidence of strong ordering of the crystalline organic film along the c-axis of the sapphire substrate (located by using one of the Raman peaks of the substrate material). These measurements allow us to estimate the angle (α0) between the plane of the molecule and that of the film (∼90 deg) as well as the angle (β0) between the substrate’s c-axis and the four-fold molecular axis.
The strength of the optical anisotropy is related to the epitaxy of the system and the degree of in-plane order, as determined by NC-AFM and surface x-ray scattering. Similar studies performed in films deposited on MgO and Si wafers, with native oxide layer, do not show the same evidence of self organized ordering.