Dresden 2009 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 21: Organic Thin Films I
DS 21.1: Vortrag
Mittwoch, 25. März 2009, 09:30–09:45, GER 38
In-situ STXM investigations of pentacene-based OFETs during operation — Christian Hub1, •Martin Burkhardt2, Marcus Halik2, George Tzvetkov1, and Rainer Fink1 — 1Department Chemistry and Pharmacy, Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen — 2Institute of Polymer Materials, Universität Erlangen-Nürnberg, Martensstraße 7, 91058 Erlangen
Thin-film pentacene-based organic field-effect transistors on commercially available silicon nitride membranes produced by high-vacuum deposition are demonstrated. The produced devices show excellent electronic performance. Due to their overall thickness below 150 nm scanning transmission x-ray microspectroscopy (STXM) experiments are possible. Zone-plate based STXM at the PolLux beamline at the Swiss Light Source provides both high chemical sensitivity and a spatial resolution less than 35 nm. Thus a correlation of the local structural and electronic properties of our devices may be established by this microspectroscopic method. Through the subtle design of our experimental setup an in-situ investigation at highest spatial and spectral resolution during OFET operation is possible to observe modifications in the electronic structure. Recorded NEXAFS spectra show a significant local dichroism. Detailed analysis of the NEXAFS spectra revealed different orientations of the pentacene nanocrystals within the film. Unfortunately spectral changes while the OFET is operated can hardly be detected with the current experimental setup. We will discuss these experimental findings in terms of relevant interface properties. This project is funded by the BMBF, contract 05 KS7WE.