Current enhancement in regioregular poly(thiophene) thin film transistors

Thin-film transistors (TFTs) made with solution-processed polymeric semiconductors are being developed for use in large-area, low-cost electronic devices such as displays. The carrier mobility in most polymers is about ten times smaller than that in amorphous silicon. To be useful for circuits, the dimensions of TFTs made with polymers must be scaled to compensate for this deficiency because high-quality, ultra-thin or high-k dielectrics are not available for these applications. Deviations from ideal FET behavior are widely reported for polymer TFTs with channel lengths shorter than ∼10 μm and these deviations are currently not understood. In this paper, we present an explanation of this phenomenon for the first time. 2D simulations will be necessary to further model the current-voltage characteristics. These data are important for the development of device models for polymeric circuits and for the determination of materials properties from I-V characteristics of TFTs.