An organic poly(3,4-ethylenedioxythiophene) field-effect transistor fabricated by spin coating and reactive ion etching

Organic field-effect transistors (OFETs) have been fabricated by the simple and low-cost fabrication processes of spin coating and reactive ion etching (RIE) with poly(styrenesulfonate) doped poly(3,4-ethylenedioxythiophene) as the p-type semiconductor, poly(4-vinylphenol) as the gate dielectric layer, and polypyrrole (PPy) as the electrodes of gate, source, and drain. The dielectric, semiconductor, gate, and source/drain layers are deposited by low-cost spin coating and patterned with the RIE technique using an aluminum thin film as the mask. The electrical characteristics of the device and the influence of PPy on the device performance have been investigated by comparing two types of OFETs with different gates, PPy as one gate and low-resistivity silicon as the other gate in an ambient atmosphere at room temperature. The OFET with PPy as the gate has a field-effect mobility of 0.58 × 10^-4 cm²/V·s with threshold voltage of -13.3 V and subthreshold slope of 6.77 V/decade.