Low hysteresis pentacene thin-film transistors using SiO ₂/cross-linked poly(vinyl alcohol) gate dielectric

Low hysteresis pentacene organic thin-film transistors (OTFTs) were fabricated using plasma-enhanced chemical vapor deposition Si O2 /cross-linked poly(vinyl alcohol) gate dielectrics. The hysteresis was considerably reduced by optimizing the thickness of the Si O2 layer. The balancing of the electrons injected from the gate electrode into the gate dielectric and the trapped holes from the channel under the optimum condition is considered to be the mechanism by which the hysteresis is reduced. In addition, the optimized OTFTs with the hybrid gate dielectric show a high dielectric constant and reliable leakage characteristics due to the advantages afforded by each gate dielectric material. The device with WL=3005 shows a field-effect mobility of 0.12 cm2 V s, a subthreshold slope of 0.4 V /decade, and an on/off ratio of 2.3× 106. The bias stress experiments conducted for the OTFTs confirmed the effect of the injected charges and hole traps on the threshold voltage shift.