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DS: Fachverband Dünne Schichten
DS 35: Organic thin films III: Monolayers and crystals
DS 35.6: Talk
Thursday, March 29, 2012, 19:00–19:15, H 2032
Organic Field-Effect Transistor Operation With Different Gatings — •Nis Hauke Hansen1, Carina Wunderlich1, and Jens Pflaum1,2 — 1Experimental Physics VI, Julius-Maximilians-University of Würzburg, D-97074 Würzburg — 2ZAE Bayern e.V., D-97074 Würzburg
To enable superior insulation characteristics together with low-voltage operation, e.g. for portable electronic devices, organic thin film transistors (TFT) can be gated by ultrathin self-assembled monolayer (SAM) dielectrics [1]. Alternatively, the choice of ionic liquids (IL) as gate dielectric allows for accumulation of high charge carrier densities in the order of 1013 cm−2, corresponding to a charge carrier doping of up to 0.3 holes per molecule. In this contribution we employed both approaches to gate TFTs based on vacuum sublimed Pentacene (PEN) and Diindenoperylene (DIP) films as semiconducting channel. The observed current-voltage (IV) characteristics show low threshold voltages between -3 and -1 V for all devices under investigation and hole mobilities up to 10−1 cm2/Vs for SAM gate dielectrics in combination with PEN as well as DIP. Utilizing an IL as gate dielectric high charge carrier densities in the order of 1013 cm−2 have been confirmed. In order to correlate the electronic performance with thin film morphology, atomic force microscopy (AFM) and x-ray diffraction (XRD) measurements have been performed indicating the influence of the respective gating on the structural properties of the molecular semiconductors.
[1] H. Klauk, et al., Nature 445 (2007) 745