High-mobility pentacene thin-film transistors with copolymer-gate dielectric

Pentacene thin-film transistors have been obtained using polymethyl-methacrylate-co-glyciclyl-methacrylate (PMMA–GMA) as the gate dielectric. The optimum active layer thickness in thin-film transistors (OTFTs) was investigated. The present devices show a wide operation voltage range. The on/off current ratio is as high as 105. In linear region (VDS=-2V), the field-effect mobility of device increases with the increase in gate field at low-voltage region (VG<-20V), and a mobility of 0.33 cm2/V s can be obtained when VG>-20V. In saturation region, the mobility increases linearly with the gate field, and a high mobility of 1.14 cm2/V s can be obtained at VG=-95V. The influence of voltage on mobility of device was investigated.