Reduction of Hysteresis in Organic Field-Effect Transistor by Ferroelectric Gate Dielectric

We studied the reduction of hysteresis in pentacene organic field-effect transistors (OFETs) with a ferroelectric poly(vinylidene fluoride and trifluoroethylene) [P(VDF-TrFE)] dipole layer used as a coating of silicon dioxide gate insulator. Although the OFETs without the dipole layer exhibited a hysteresis caused by carrier trapping, such hysteresis was not observed for the OFETs with the P(VDF-TrFE) layers. Experiments showed that the induced hysteresis could be regulated by the number of P(VDF-TrFE) dipole layers, which were deposited by the Langmuir-Blodgett (LB) technique or the spin-coating method. Finally, we showed that analysis based on an electrostatic model well accounted for the experimental results, i.e., the reduction of hysteresis by means of the ferroelectric layer. (C) 2010 The Japan Society of Applied Physics