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SYOH: Organic and Hybrid Systems for Future Electronics
SYOH 5: Poster
SYOH 5.38: Poster
Donnerstag, 11. März 2004, 18:00–21:00, B
Chemistry and Electronic Properties of Mg/PTCDA Interface — •G. Gavrila1, H. Mendez1, T. Kampen1, D. Vyalikh2, W. Braun 2, and D.R.T Zahn1 — 1Institut für Physik, TU Chemnitz, 09107 Chemnitz, Germany — 2BESSY GmbH, 12489 Berlin, Germany
The chemical and electronic properties of interfaces formed between an organic semiconductor, i.e. 3,4,9,10-perylene-tetracarboxylic dianhydride (PTCDA), and the low electron affinity metal Mg were investigated using Near Edge X-ray Absorption Fine Structure (NEXAFS) and PhotoEmission Spectroscopy (PES). NEXAFS spectra taken for C K-edge and O K-edge of PTCDA show that the intensity in the π*-resonance decreases after deposition of Mg. This is interpreted as a partial occupation of the lowest unoccupied molecular orbital. Since Mg possesses a smaller electronegativity than PTCDA, a negative charge transfer from Mg to PTCDA can be expected. Changes in C1s and O1s core levels and the valence band structures corroborate this interpretation. Moreover, changes in the C=O component of core levels indicate a strong chemical reaction of Mg with the organic material. Previous work based on Raman Spectroscopy and NEXAFS revealed considerable differences between Mg/PTCDA and Ag/PTCDA interfaces. Here, it was found that the Ag atoms do not disrupt the chemical structure of the PTCDA and do not diffuse into the organic film.