Low Operating Voltage and High Mobility Field Effect Transistors Comprising Pentacene and Relatively High Dielectric Constant Insulators

Insulated Gate Field Effect Transistors (IGFET) comprising pentacene as the semiconductor layer and silicon dioxide or amorphous metal oxide gate insulators were fabricated and tested. The gate bias dependence of the field effect mobility in pentacene IGFETs was interpreted based on the interaction of charge carriers with localized trap levels in the band gap. This understanding was used to design and fabricate IGFETs with field effect mobility values up to 0.6 cm² V^-1 s ^-1, subthreshold slopes as low as 0.3 V/decade and current modulation higher than 10⁵. Most importantly, these values were obtained at operating voltage ranges as low as 5 volts, which are much narrower than previously reported results. IGFETs fabricated by an all room temperature process on polycarbonate substrates and exhibiting similar transport characteristics were also demonstrated, clearly showing their compatibility and lightweight plastic substrates.