Low-Temperature-Processed Inorganic Gate Dielectrics for Plastic-Substrate-Based Organic Field-Effect Transistors

Low-temperature-processed inorganic gate dielectrics were employed here to yield high-performance organic field-effect transistors (FETs) on flexible plastic substrates. SiN_x dielectrics deposited at room temperature and SiN_x/sol-gel silica dielectric bilayer processed below 100degC were demonstrated to be viable gate dielectric materials, with the latter yielding effective field-effect mobilities of ~ 1 cm²/Vldrs at operating voltages of under -5 V with an on-off current ratio in the range of 10⁵. The enhancement in device performance was attributed to an improved semiconductor-dielectric interface and a larger grain size of the pentacene deposited on the bilayer dielectrics. The flexibility of FETs fabricated on polyester substrates was also demonstrated with insignificant changes in device performance upon subjecting the devices to strains of 2.27%.