Reduction of threshold voltage fluctuation for organic field effect transistors by increase of insulator capacitance

Fluctuation of threshold voltages for top contact organic field effect transistors with pentacene active layers were successfully reduced by increase of gate insulator capacitance. Average fluctuation of threshold voltages of devices with 1000-nm-SiO2-insulator was approximately 4 V, however it became only 0.5 V when the SiO2 thickness was reduced to 100 nm. Since a vast number of transistors with constant threshold voltage are needed for application to displays, increase of capacitance would be a useful method for improving the reliability of OFETs.