The dynamic performance of organic thin-film transistors (TFTs) can be significantly improved by utilizing organic semiconductors with a larger field-effect mobility and by reducing the lateral TFT dimensions, i.e., the channel length and the parasitic gate overlap. For example, by replacing the popular oligoacene pentacene with the fused thienoacene dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) or one of its derivatives, such as C10-DNTT and DPh-DNTT (all developed by Kazuo Takimiya et al.), we have been able to increase the field-effect mobility of flexible, low-voltage p-channel organic TFTs from less than 1 cm2/Vs to about 5 cm2/Vs (measured in long-channel devices). More importantly, by taking advantage of high-resolution silicon stencil masks developed in collaboration with the Institute for Microelectronics Stuttgart (IMS Chips) we have been able to reduce the lateral TFT dimensions to 0.5 µm. As a result, we have been able to reduce the signal delay of flexible organic p-channel TFTs (measured in unipolar ring oscillators at a supply voltage of 3 V) from about 100 µsec per stage to less than 100 nsec per stage.

Small contact resistance and high-frequency operation of flexible low-voltage inverted coplanar organic transistors
J. W. Borchert, B. Peng, F. Letzkus, J. N. Burghartz, P. K.L. Chan, K. Zojer, S. Ludwigs, H. Klauk
Nature Communications, vol. 10, pp. 1119/1-11, March 2019

Megahertz operation of flexible low-voltage organic thin-film transistors
U. Zschieschang, R. Hofmockel, R. Rödel, U. Kraft, M. J. Kang, K. Takimiya, T. Zaki, F. Letzkus, J. Butschke, H. Richter, J. N. Burghartz, H. Klauk
Organic Electronics, vol. 14, no. 6, pp. 1516-1520, June 2013

AC characterization of organic thin-film transistors with asymmetric gate-to-source and gate-to-drain overlaps
T. Zaki, R. Rödel, F. Letzkus, H. Richter, U. Zschieschang, H. Klauk, J. N. Burghartz
Organic Electronics, vol. 14, no. 5, pp. 1318-1322, May 2013

S-parameter characterization of submicrometer low-voltage organic thin-film transistors
T. Zaki, R. Rödel, F. Letzkus, H. Richter, U. Zschieschang, H. Klauk, J. N. Burghartz
IEEE Electron Device Letters, vol. 34, no. 4, pp. 520-522, April 2013

Contact Resistance and Megahertz Operation of Aggressively Scaled Organic Transistors
F. Ante, D. Kälblein, T. Zaki, U. Zschieschang, K. Takimiya, M. Ikeda, T. Sekitani, T. Someya, J. N. Burghartz, K. Kern, H. Klauk
Small, vol. 8, no. 1, pp. 73-79, January 2012

Flexible low-voltage organic thin-film transistors and circuits based on C₁₀-DNTT
U. Zschieschang, M. J. Kang, K. Takimiya, T. Sekitani, T. Someya, T. W. Canzler, A. Werner, J. Blochwitz-Nimoth, H. Klauk
Journal of Materials Chemistry, vol. 22, no. 10, pp. 4273-4277, February 2012

Flexible Low-Voltage Organic Transistors and Circuits Based on a High-Mobility Organic Semiconductor with Good Air Stability
U. Zschieschang, F. Ante, T. Yamamoto, K. Takimiya, H. Kuwabara, M. Ikeda, T. Sekitani, T. Someya, K. Kern, H. Klauk
Advanced Materials, vol. 22, no. 9, pp. 982-985, March 2010

Low-voltage organic thin-film transistors with large transconductance
H. Klauk, U. Zschieschang, M. Halik
Journal of Applied Physics, vol. 102, no. 7, pp. 074514/1-7, October 2007