Enhancement in the Mobility and the Stability of Solution-Processed ZincTin Oxide Thin-Film Transistors Using Alkali Metal Superoxide

Abstract

We have studied how to improve the mobility and stability of solution processed zinc-tin oxide thin-film transistors (ZTO TFTs) simultaneously using multifunctional potassium superoxide precursor. Potassium cations in the potassium superoxide precursor acts as a shallow donor in the ZTO thin film to improve the carrier concentration (electron), which allows the potassium-doped ZTO TFT to exhibit high mobility. Then, the anion of the precursor exists as a superoxide radical, and it showed the effect of reducing the oxygen vacancy in the process of forming the oxide thin film. Consequently, potassiumdoped ZTO TFT using potassium superoxide precursor exhibited improved mobility and stability, showing an increase in the mobility from 5.11 to 8.36 cm2/Vs and a decrease in the threshold voltage shift from 4.65 to 3.36 V under a negative bias temperature illumination stress test conducted over 5,000 sec..