Environmentally friendly, flexible and high performance PVA dielectric layer fabricated by solution method and its application in IGZO-TFT

Abstract At present, Poly (Vinyl Alcohol) (PVA)is often used as the dielectric layer of thin film transistors (TFT)because of its good insulation and environmental protection. However, because of the hydroxyl groups on the surface, PVA films have poor contact with electrodes and semiconductors. Therefore, in this paper, we proposed an effective way to make PVA molecules curled up by applying dual solvent system with water and ethanol. As a result, the leakage current density is reduced from 1.2 × 10−4 A/cm [2]@0.5 mV/cm to 6.2 × 10−6 A/cm [2]@0.5 mV/cm. Moreover, we adjusted the molecular morphology of PVA in the solution by optimizing the configuration sequence of the precursor solution, so as to obtain a PVA film with better performance, with a leakage current density of only 5.9 × 10−7 A/cm [2]@0.5 mV/cm. The change in molecular morphology can be seen from the solution viscosity and surface tension measurements. Finally, we prepared IGZO-TFT devices for comparison, and it is proved that the PVA films prepared after changing the configuration sequence have better application in TFT, with a mobility of 8.19 cm2V−1s−1 and a switching ratio of 2.76 × 106.