Low-voltage pentacene field-effect transistors with ultrathin polymer gate dielectrics

Abstract

Organic field-effect transistors (OFETs) for low-voltage operation have been realized with conventional polymer gate dielectrics such as polyimides and cross-linked poly-4-vinyl phenols (PVPs) by fabricating ultrathin films. These ultrathin polymers (thickness ∼10nm) have shown good insulating properties, including high breakdown fields (>2.5MV∕cm). With ultrathin dielectrics, high capacitances (>250nF∕cm2) have been achieved, allowing operation of OFETs within −3V. Pentacene OFETs with ultrathin PVP dielectrics exhibit a mobility of 0.5cm2∕Vs, an on-off ratio of 105, and a small subthreshold swing of 174mV∕decade when devices are operated at −3V.