Flexible ZnO transparent thin-film transistors by a solution-based process at various solution concentrations

We report solution-processed ZnO thin-film transistors (TFTs) on a flexible substrate, using polymethylmethacrylate (PMMA) as a dielectric layer. To improve the compatibility between the ZnO active layer and the PMMA dielectric, an O2-plasma treatment has been applied to the PMMA dielectric. The structural and electrical characteristics of the ZnO-TFTs, which have different channel morphologies produced by various concentrations of the ZnO solution, were investigated. The ZnO trap centers of the ZnO-TFTs were decreased as the concentration of the ZnO solution increased. The ZnO-TFT with the optimized channel morphology exhibited a high field-effect mobility of 7.53 cm2 V-1 s-1.