Performance and Fabrication of Organic Field Effect Transistor with Active Layer Prepared by Soluble Pentacene

An organic field-effect transistor (OFET) was prepared with thin film fabricated by soluble pentacene as the semiconductor layer, polyimide thin film as the gate insulating layer, and Au as the drain, source and gate electrodes. The pentacene and polyimide thin films were fabricated by the cast and spin coat methods. The carrier mobility of the organic field-effect transistor was 1.2 x 10(-2) cm2/ Vs. The ON/OFF ratio was 3 x 10(2). As compared with the carrier mobility of OFET prepared by the evaporation method, their values were the same as that of the spin-coating method. However, the ON/OFF ratio obtained was lower. This indicates that it is either the leakage current in polyimide thin film that is large or it is that of the off-current of the pentacene thin film.