dThe organic field-effect transistors with poly(styrenesulfonate)-doped poly(3,4-ethylenedioxythiophene) (PEDT/PSS) as p-type semiconductor are fabricated on heavily doped silicon substrate working as the gate. Dielectric layer, semiconductor, and source/drain layer are deposited by spin coating and then patterned with UV lithography and RIE techniques using aluminum thin film as the mask. The electrical characteristics of the device have been investigated in the atmosphere at room temperature. The devices have field-effect mobility as high as 0.8 cm(2)/V S, on/off current ratio larger than 10(5), threshold voltage of 9.3 V, and subthreshold slope of 4.5 V/decade. (C) 2003 Elsevier Ltd. All rights reserved.