High Electrical Performance of Wet-Processed Indium Zinc Oxide Thin-Film Transistors

We developed thin-film transistors (TFTs) that use solution-processed amorphous indium zinc oxide for the channels in an all-photolithographic process. The transistors, which operate in depletion mode, have excellent transfer characteristics, including saturation mobility of 6.57 $\hbox{cm}^{2}/ \hbox{V}\cdot\hbox{s}$, threshold voltages of $-$ 0.30 V, turn-on voltages of $-$1.50 V, on/off ratios of $\hbox{10}^{9}$, and inverse subthreshold slopes of 0.15 V/dec. We measured the time, temperature, gate voltage, and drain-voltage dependence of the threshold voltage shift, which was 2.16 V under stress conditions. This is nearly the same as that of conventional amorphous silicon TFTs.