Electrical In-Situ Characterisation of Organic Thin Film Transistors
B. Striedinger, A. Fian, R. Lassnig, A. Winkler, B. Stadlober
Joanneum Research Materials
15:20 - 17:30 Thursday 24 October 2013 Foyer Alte Technik Organic thin film transistors (OTFTs) are an emerging technology in the broad field of organic electronics. They are a key building block for many contemplated and widely discussed future applications with RFID-tags and backplanes for flexible displays amongst the most prominent candidates. The deployment of OTFTs in such circuit applications demands a high degree of uniformity from individual devices. In order to achieve that kind of uniformity, understanding and controlling the growth modes and thus the morphology of the first few monolayers of the organic semiconductor is imperative, for it is those first monolayers in which charge transport mainly occurs.
In the present contribution we report on electrical in-situ characterisation of p-type OTFTs in bottom-gate bottom-contact geometry, implementing pentacene as organic semiconductor. The organic semiconductor is evaporated on pre-fabricated model device structures by organic molecular beam evaporation in a high vacuum system which enables parallel in-situ electrical characterisation during the ultra-slow deposition of the semiconductor film. Thus the experimental setup allows for the analysis of the dynamics of channel formation and its dependence on morphology and thickness of the semiconductor. The charge carrier mobility and other transistor parameters are investigated in context of the number of monolayers deposited. The layers are furthermore characterised ex-situ by atomic force microscopy.
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