Current saturation effect for pentacene-based static induction transistor under negative drain-source and gate voltages

Usually, the drain-source current (IDS) increases with positive drain-source voltage (VDS) for pentacene-based organic static induction transistor (OSIT) ITO(Source)/Pentacene/Al(Gate)/Pentacene/Au(Drain) and it shows an inherent rectifying property under negative gate voltages (VG), i.e. the slope of IDS vs. VDS curve increases with VDS but without any current saturation effect. In this paper, we investigated the electrical characteristics of pentacene-based OSIT ITO/Pentacene(80 nm)/Al(15 nm)/Pentacene(80 nm)/Au under negative VDS and VG, and found that IDS changed from rectifying property to saturation effect when the magnitude of negative VDS was increased from 0 V to −6 V under negative VG, and the turn-on voltage (VON) moved to larger negative voltages when the magnitude of negative VG increased and the movement step of VON gets smaller after keeping the device for a long time, and the possible mechanisms for such a kind of current modulation were discussed.