Regensburg 2000 – scientific programme
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HL: Halbleiterphysik
HL 30: Organische Bauelemente
HL 30.3: Talk
Thursday, March 30, 2000, 11:00–11:15, H13
Optical investigations of organic / semiconductor heterosystems — •G. Salvan, M. Friedrich, T. U. Kampen, and D. R. T. Zahn — Institut für Physik, Technische Universität Chemnitz, D-09107 Chemnitz, Germany
Vibrational properties of an organic prototype molecule, 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) deposited on silicon, were investigated in order to illuminate the organic/semiconductor hetero-interface formation. PTCDA films were grown on Si (100) and Si (111) by organic molecular beam deposition (OMBD). In situ and on-line Raman spectroscopy was performed close to resonant conditions. Complementary, Fourier transform infrared spectroscopy (FTIR) measurements were carried out ex situ in reflection and transmission. The growth parameters (the surface treatment and the temperature of substrate during the growth) were varied in order to determine critical values at which reactions occur. Raman spectra show variations in the region of internal modes having a high contribution from the C-H deformation vibrations and below 100 cm−1, where the phonon lines occur. These changes will be discussed using the spectra of crystalline PTCDA as reference [1]. Additional information relative to the orientation of PTCDA molecules with respect to the substrate is extracted from the behaviour of infrared-active out-of-plane C-H deformation bands below 1000 cm−1.
[1] T. U. Kampen, D. A. Tenne, S. Park, G. Salvan, R. Scholz and D. R. T. Zahn, Phys. Stat. Sol. (B), 215, 431 (1999).