Characterization of intrinsic hysteresis of pentacene-based organic thin-film transistor through in-situ real-time electrical measurement

摘要

The intrinsic hysteresis of a pentacene-based organic thin-film transistor was characterized through home-designed in-situ real-time electrical measurement. The device exhibited intrinsic hysteresis after the device fabrication without breaking the vacuum, which has not been observed previously. Similar behavior was observed when introducing the nitrogen gas. Compared with the measurement condition of vacuum or nitrogen gas, exposure to the ambient air resulted in a severe hysteresis. It was attributed to both the acceptor-like traps at the organic/dielectric interface and the donor-like traps in the transport channel. When the chamber was vacuumed out again, a significantly reduced hysteresis was obtained almost the same as that measured just after device fabrication, indicating the reversibility of the extrinsic hysteresis. We also related the hysteresis to the morphological change under different deposition rates of pentacene. The smoother surface at higher deposition rate caused reduced hysteresis because of the elimination of vacancies near the pentacene/dielectric interface.