High-Performance Static Induction Transistors Based on Small-Molecule Organic Semiconductors

The polymeric organic-static-induction transistor (OSIT), a solid-state vacuum triode, has been extensively studied as a promising vertical organic thin-film transistor. By utilizing polymers as organic semiconductors in OSITs, important performance figures have been achieved, for example, a maximum on-current output of about 10 mA cm⁻², on/off current ratio as high as 10⁵, and a large current gain of 1000. However, even though polymers with higher mobility have been developed, the performance of OSITs has not been significantly improved yet. In this work, record-high performance OSITs with small-molecule materials as organic semiconductors are demonstrated. Pentacene as a hole-transport material for p-type OSITs can be easily deposited into pinholes of the gate electrode, hence creating effective conducting channels. Excellent characteristics, such as a high on-current greater than 260 mA cm⁻², on/off current ratio up to 3.3 × 10⁵, and a large transmission factor of 99.98% as well as high current gain of 7965, are attained. These results make the small-molecule organic semiconductor a candidate material for vertical OSITs as well as for organic electronics.