Study of organic thin film transistor with polymethylmethacrylate as a dielectric layer

The properties of pentacene-based organic thin film transistors (OTFTs) with polymethylmetha-crylate (PMMA) as a dielectric layer have been investigated. The concentration of PMMA was about 8wt% with toluene as solvent. The pentacene film on PMMA dielectric layer displays high thin film quality according to results of x-ray diffraction scan and atomic force microscopy. The crystalline size was about 33.96nm and the grain size was about 1000–1500nm. The pentacene-based OTFTs with PMMA as a dielectric layer exhibited excellent electric characteristics, including a high mobility of 0.241cm2∕Vs or larger, an on/off current ratio of 104 or larger, and the threshold voltage of less than −6.3V.