Effect of Chloride Precursors on the Stability of Solution-Processed Indium Zinc Oxide Thin-Film Transistors

Abstract

In this experiment, solution-processed indium zinc oxide (IZO) films were prepared by spin-coating the films as an active layer in thin-film transistors (TFTs). These films were coated with nitrate and a mixture of acetate- and chloride-based precursors to allow the IZO films to contain indium and zinc components. The solution-processed IZO-based TFT fabricated using a zinc acetate precursor for the IZO films exhibited a mobility of 2.83 cm2 V-1 s-1, an on/off current ratio of ∼1×105, and a subthreshold swing value of 2.48 V/dec. The IZO-TFT with the zinc chloride precursor exhibited a mobility of 4.37 cm2 V-1 s-1, an on/off current ratio of ∼1×103, and a subthreshold swing value of 6.44 V/dec. In comparison, the IZO-TFT with a mixture of zinc acetate and chloride precursors exhibited a mobility of 1.45 cm2 V-1 s-1, an on/off current ratio of ∼1×105, and a subthreshold swing value of 1.83 V/dec. The first two devices suffered from a large threshold voltage (Vth) shift, >7 and >6 V, respectively, after a gate voltage of 20 V was applied for 2 h. In contrast, the device fabricated using the mixed precursors showed a higher stability, shifting about 1.7 V under the same stress conditions.