Effects of gate dielectric composition on the performance of organic thin-film devices

Four poly(4-vinyl phenol) based gate dielectrics were tested to optimize the performance of pentacene organic field-effect transistors. The dielectrics’ surface tensions, Fourier transform infrared spectra, capacitances and leakage currents were measured. The optimal dielectric allowed the transistor to show negligible hysteresis with high performance even in ambient conditions. A complementary inverter was fabricated by integrating in single substrate pentacene (p-type) and F16CuPc (n-type) OFETs containing the optimized gate dielectric. Its voltage transfer curve showed almost symmetric noise margin; it showed a logic threshold of 22.5 V and a maximum voltage gain (δVout/δVin) of 6.2 at Vin = 22.5 V.