Performance improvement and evaluation of an all plastic organic field effect transistor

Abstract

We have fabricated organic thin film transistors with a polyehylenenaphthalate (PEN) film as the substrate, a poly (3- hexylthiophene) (P3HT) thin film as the semiconductor layer and a cross-linked poly-4-vinylphenol (PVP) thin film as the gate dielectric layer. The performance of the P3HT-FET, fabricated using the spin-coated P3HT thin film, is as follows. The mobility is 4.0×10^-4cm²/Vs and the threshold voltage is -13V. On the other hand, P3HT-FET fabricated using the drop-cast thin film is as follows. The mobility is 2.0×10^-2cm²/Vs and the threshold voltage is -2V. Furthermore, the performances of the top and bottom contact P3HT-FETs were also evaluated as part of investigations into the charge injection from electrodes to the P3HT thin film and the interface traps between the P3HT thin film and electrodes. In terms of the performance of top contact P3HT-FET, the mobility is 7.0×10^-2 cm²/Vs and the threshold voltage is 5V, which are values far superior to those of the bottom contact P3HT-FET. This indicates that in the top contact P3HT-FET, the contact resistance of the interface between the P3HT thin film and electrode is lower than that of the bottom contact P3HT-FET.