Regensburg 2007 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 7: Organic Film Aging (SYOE 3)
DS 7.1: Vortrag
Montag, 26. März 2007, 18:00–18:15, H32
In situ studies of gas influence on the transport properties of organic thin-film transistors — •Sven Issing, Markus Michelfeit, Michael Leufgen, Jean Geurts, Georg Schmidt, and Laurens Molenkamp — Universität Würzburg, physikalisches Institut (EP3), Am Hubland, D-97074 Würzburg, Germany
The stability of organic thin-film transistors (OTFT) remains a critical issue for applications. Especially the influence of different ambient atmospheres needs systematic investigation. Therefore, we fabricated OTFTs with dihexylquarterthiophene (DH4T) as active material by organic molecular-beam deposition in ultra high vacuum (UHV) and performed in situ electrical characterization. Afterwards the OTFTs were exposed to different gases in the UHV-chamber: ambient air, dry air, oxygen, nitrogen or argon up to 1 · 10−2 mbar·s (= 104 Langmuir). The charge carrier mobility µ and the threshold voltage VTh were measured vs. exposure. Furthermore, we investigated the relaxation after termination of the gas flow. The onset of a change of µ and VTh is observed at ≈100 L. µ (initially ≈10−2 cm2/Vs) shows a relative decrease between 51% (for argon) and 73% (for oxygen). In clear contrast to the other exposures, for oxygen a shift of VTh towards less negative values is observed. Both µ and VTh showed no reversibility after the exposure.
This work was supported by the EU Integrated Project NAIMO (No NMP4-CT-2004-500355)