Improved performance of pentacene field-effect transistors using a polyimide gate dielectric layer

Abstract

Organic field-effect transistors using pentacene have been fabricated employing polyimide gate dielectric layers. The root-mean square surface roughness of polyimide films is 9 Å. Devices with thin polyimide films as gate achieved a mobility of 0.16 cm2 V−1 s−1, threshold voltage −6.4 V, on–off ratio ∼ 104 and subthreshold slope 7.5 dec−1 with the gate voltage span between 0 and −30 V. The upper limit of interface trap density has been estimated to be 3.9 × 1012 cm−2 eV−1. The mobility is found to be gate bias dependent.