Single-Crystal Organic Field Effect Transistors with the Hole Mobility ~ 8 cm2/Vs

We report on the fabrication and characterization of single-crystal organic p-type field-effect transistors (OFETs) with the field-effect hole mobility mu \~ 8 cm2/Vs, substantially higher than that observed in thin-film OFETs. The single-crystal devices compare favorably with thin-film OFETs not only in this respect: the mobility for the single-crystal devices is nearly independent of the gate voltage and the field effect onset is very sharp. Subthreshold slope as small as S = 0.85 V/decade has been observed for a gate insulator capacitance Ci = 2 +- 0.2 nF/cm2. This corresponds to the intrinsic subthreshold slope Si = SCi at least one order of magnitude smaller than that for the best thin-film OFETs and amorphous hydrogenated silicon (a-Si:H) devices.