Functionalized pentacene field-effect transistors with logic circuit applications

Abstract Funtionalized pentacene, 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene), field-effect transistors(FET’s) were made by thermal evaporation or solution deposition method andthe mobility was measured as a function of temperature and light power. The field-effect mo-bility (µ FET ) has a gate-voltage dependent activation energy. A non-monotonic temperature de-pendence was observed at high gate voltage (V G < -30 V) with activation energy E a ∼ 60 -170 meV,depending on the fabrication procedure. The gate-voltage dependent mobility and non-monotonic temperature dependence indicates that shallow traps play important role in the trans-port of TIPS-pentacene films. The current in the saturation regime as well as mobility increaseupon light illumination and is proportional to the light intensity, mainly due to the photocon-ductive response. Transistors with submicron channel length showed unsaturating current-voltagecharacteristics due to the short channel effect. Realization of simple circuits such as NOT(inverter),NOR, and NAND logic gates are demonstrated for thin film TIPS-pentacene transistors.