Performance and transport characteristics of α,ω-dihexylsexithiophene- based transistors with a high room-temperature mobility of 0.16cm2∕Vs

Organic thin-film transistors (OTFTs) based upon α,ω-dihexylsexithiophene (DH6T) have been fabricated and characterized. The DH6T thin films were prepared using neutral cluster beam deposition (NCBD) methods on room-temperature SiO2 substrates. The effects of surface modification were examined. The geometric effects of the gate dielectric thickness, channel length, and width on the device characteristics were also systematically studied. A combination of the NCBD technique and octadecyltrichlorosilane (OTS) pretreatment was most efficient for producing high-quality crystalline DH6T films. The temperature dependence of the field-effect mobility (μeff) indicated that the transistor performance was strongly correlated with the structural and morphological properties of the DH6T active layers and that the surfactant pretreatment significantly enhanced the μeff. A room-temperature μeff of 0.16cm2∕Vs for the OTS-pretreated transistors was found to be best so far reported for DH6T-based OTFTs using a SiO2 gate dielectric layer.