PENTACENE-BASED ORGANIC THIN FILM TRANSISTOR WITH SiO2 GATE DIELECTRIC

An organic thin film transistor (OTFT) based on pentacene was fabricated with SiO 2 as the gate dielectric material. We have investigated the effects of the thickness of pentacene layer and the organic semiconductor (OSC) material on OTFT devices at two different thicknesses. Au metal was deposited for gate, source and drain contacts of the device by using thermal evaporation method. Pentacene thin film layer was also prepared with thermal evaporation. Our study has shown that the change in pentacene thickness makes a noteworthy difference on the field effect mobility (μFET), values, threshold voltages (VT) and on/off current ratios (Ion/Ioff). OTFTs exhibited saturation at the order of μFET of 3.92 cm2/Vs and 0.86 cm2/Vs at different thicknesses. Ion/Ioff and VT are also thickness dependent. Ion/Ioff is 1 × 103, 2 × 102 and VT is 15 V, 27 V of 40 nm and 60 nm, respectively. The optimized thickness of the pentacene layer was found as 40 nm. The effect of the OSC layer thickness on the OTFT performance was found to be conspicuous.