Hole transport in polycrystalline pentacene transistors

Measurements of pentacene thin-film transistors are used to explore hole transport mechanisms. The grain-boundary barrier model does not account for the data, since no field dependence of the mobility is observed over a wide range of gate and drain voltages. Instead, trapping provides a more satisfactory qualitative and quantitative interpretation. The subthreshold characteristics are attributed to deep acceptors in the pentacene film, and the conclusions are supported by numerical modeling. (C) 2002 American Institute of Physics.