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

Abstract

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 m 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 m, respectively. #

Current Status and Opportunities of Organic Thin-Film Transistor Technologies

“…6 summarizes the measured f T of OTFTs from selected works achieving the best results, which are classified with respect to the fabrication methods adopted for the patterning of the electrodes and for the deposition of the OSC layer [43], [118]- [127]. The record f T reported to date reaches the value of 27.7 MHz for a device based on C 60 with a channel length of 2 μm defined by photolithography [119]. Recently, OTFTs with f T of 20 MHz were fabricated by means only of scalable coating techniques and laser-based directwriting methods with a completely mask-less procedure [124].…”

Injection Length in Staggered Organic Thin Film Transistors: Assessment and Implications for Device Downscaling

“…[2][3][4][5][6][7][8][9][10][11][12] Therefore by scaling the channel length down to 10-1 μm, in principle OTFTs should be able to operate at relatively high (1-10 MHz) frequencies at reasonable (<10 V) applied voltages. [ 13 ] In practice, apart from some reports, [13][14][15][16][17][18][19][20][21][22] this is often not easy to achieve because of injection issues: [ 23,24 ] contact resistances tend to become dominant over the channel resistance in short channel transistors reducing the expected improvement of device performances. [ 25 ] This situation is severely limiting the range of applications for OTFTs.…”

Solvent-Free Toner Printing of Organic Semiconductor Layer in Flexible Thin-Film Transistors

“…The Au contact electrodes were thermally evaporated using a shadow mask, and the channel length and width were 20 µm and 3.5 mm, respectively. The Au contact electrodes were chemically treated with pentafluorobenzenethiol to reduce the contact resistance [40][41][42][43][44]. This substrate is called the base film in this work.…”