Single-crystal organic field effect transistors with the hole mobility ∼8 cm2/V s

We report on the fabrication and characterization of single-crystal organic p-type field-effect transistors (OFETs) with the field-effect mobility μ∼8 cm2/V s, 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. The 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 (α-Si:H) devices.