Low-temperature self-curable polyacrylate copolymer gate insulator for hysteresis-free organic field-effect transistors

We report on the fabrication of hysteresis-free organic field-effect transistors (OFETs) and metal-insulator-semiconductor (MIS) capacitors that utilize self-curable polyacrylate type copolymer (L-PA) as a gate insulator. Superior to previously reported polymer gate insulators, L-PA for the first time enables hysteresis-free OFETs and MIS capacitors through a low temperature (110-140 degrees C) curing process, which is compatible with the conventional plastic substrates (T(g) < 150 degrees C) for flexible electronics. The dielectric film showed high dielectric strength >4.5 MV/cm and low leakage current density of 5 x 10(-9)-10(-8) A/cm(2) at 1 MV/cm, while the transistors displayed a decent field-effect mobility (mu) of 0.91 cm(2)/V s, on/off current ratio (I(on)/I(off)) of 10(6) and inverse subthreshold slope (SS) as low as 1.13 V/dec. Chemical changes were verified by FT-IR, DSC (differential scanning calorimetry) and TGA (thermo-gravimetric analysis) experiments and the surface properties of dielectrics and morphology of pentacene layers were also examined and correlated with OFET device performance. (C) 2011 Elsevier B. V. All rights reserved.