High Current-Gain Cutoff Frequencies above 10 MHz in n-Channel C₆₀ and p-Channel Pentacene Thin-Film Transistors

The current-gain cutoff frequencies for bottom contact n-channel C 60 and p-channel pentacene thin-film transistors (TFTs) with channel lengths of 2–10 µm have been investigated. The cutoff frequency was estimated by direct measurement of the gate and drain modulation currents. The measured cutoff frequencies for both C 60 and pentacene TFTs increase consistently with reducing channel length. Cutoff frequencies of 27.7 and 11.4 MHz were obtained from C 60 and pentacene TFTs with a channel length of 2 µm, respectively.