Megahertz operation of organic field-effect transistors based on poly(3-hexylthiopene)

Switching speed is crucial for many applications in organic electronics. The possibility to achieve higher frequencies will enable new fields of applications. The authors demonstrate high-frequency organic thin film transistors based on poly(3-hexylthiophene). Transistors with submicron channel lengths show unity-gain bandwidth of 2MHz in air at low supply voltages of 10V. For channel lengths L below 500nm deviations from ideal L scaling law are observed experimentally, which are attributed to contact effects. They present a model beyond the ideal scaling law to predict the maximum operational frequency based on transistor parameters, geometry, and contact resistance.