High-speed organic single-crystal transistors gated with short-channel air gaps: Efficient hole and electron injection in organic semiconductor crystals

Abstract

Short-channel, high-mobility organic filed-effect transistors (OFETs) are developed based on single crystals gated with short-channel air gaps. The high hole mobility of 10cm2/Vs for rubrene, and high electron mobility of 4cm2/Vs for PDIF-CN2 crystals are demonstrated even with a short channel length of 6μm. Such performance is due to low contact resistance in these devices estimated to be as low as ∼0.5kΩ cm at gate voltage of −4V for rubrene. With the benefit of the short channel length of 4.5μm in a new device architecture with less parasitic capacitance, the cutoff frequency of the rubrene air–gap device was estimated to be as high as 25MHz for drain voltage of −15V, which is the fastest reported for p-type OFETs, operating in ambient conditions.