Total reversibility of hysteresis in the transfer characteristics of organic thin-film transistor based on pentacene for nonvolatile memory applications

In this work, we have investigated the reversibility of hysteresis phenomena in the transfer characteristics of pentacene-based organic thin-film transistors. A clear hysteresis behavior in transfer characteristics is reported. A forward and backward scan of the gate voltage measurements reflected the appearance of hysteresis that arises due to humidity effect. Under vacuum, the hysteresis phenomenon is due to a purely electrical phenomenon based on the creation, trapping, and de-trapping of traps while under humidity the hysteresis is attributed to the diffusion of water molecules and/or oxygen into the organic active layer. The hysteresis width continuously increases with increasing the humidity in the linear and saturation regime. In contrast, the hysteresis significantly reduced under vacuum after pumping of 48 h. Consequently, the increase in hysteresis in the linear and saturation regimes arise due to humidity could be eliminated by a simple pumping under vacuum indicating the reversibility process. Based on these results, the investigated devices will be promising for some practical applications, such as nonvolatile memory device.