Electrically stable polymer-only dielectrics for organic field-effect transistors with low gate leakage current

Abstract

Organic-only dielectric films are needed for several electronic applications, particularly in organic field-effect transistors (OFETs). Here, cyclic olefin copolymer (COC) films with the thickness on the order of 100 nm are reported as satisfactory dielectric layers for high-performance and reliable OFETs. The COC dielectric film has a high glass-transition temperature and low free volume, which contribute to its superior insulating properties and high dielectric strength. Moreover, the smooth surface morphology and low surface energy of the COC film are responsible for the formation of highly crystalline structures of the overlying pentacene molecules. Finally, the OFETs with the COC dielectric layers are found to exhibit charge-carrier mobilities up to 1.075 ± 0.05 cm2/V and on/off ratios exceeding 106 while displaying low gate leakage current and negligible hysteresis.