Low-voltage organic devices based on pristine and self-assembled monolayer-treated HfTiOx gate dielectrics
Abstract
Low-voltage organic field-effect transistors (OFETs) and complementary metal oxide semiconductor (CMOS) inverters based on pentacene and N,Nā²-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13) were fabricated on HfTiOx gate dielectrics. Both pristine dielectrics and substrates passivated with self-assembled monolayers (SAMs) of n-dodecylphosphonic acid (PA-C12) were employed. The high capacitance and low leakage current of the HfTiOx-based dielectrics enabled the devices to operate at |V| < 3 V. Passivation with PA-C12 was highly effective in improving the device characteristics. In particular, an electron mobility of 0.72 cm2 Vā1 sā1 was measured for the device fabricated with the passivated HfTiOx dielectric, which represents the best performance reported to date for perylene-based OFETs prepared with thin, high-k gate dielectrics. The CMOS inverters exhibited fast switching and high gain characteristics, which were attributed to good coupling between the optimized p- and n-type OFETs.