  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.
