Fringe field effect on electrical characteristics of pentacene thin-film transistors

This paper reports the effects of the fringe field on the operating characteristics of geometrically-modified pentacene thin-film transistors (TFTs) with a polymeric gate insulator. When the dimensions of the pentacene film structurally exceeded the channel region, the output current at a given voltage was overestimated by the extra charge carriers, which were affected by the fringe field in the peripheral territory away from the channel region. By examining the range of operating frequencies, the fringe field was found to have a much more serious effect at low frequencies due to the slow movement of charge carriers stored around the periphery of the patterned source and drain electrodes. This suggests that minimizing the fringe field is important for improving the dynamic characteristics of the organic transistor-based circuits operating at low frequencies.