Dual-Functional Superoxide Precursor To Improve the Electrical Characteristics of Oxide Thin Film Transistors

We investigated a method to simultaneously improve the mobility and reliability of solution-processed zinc tin oxide thin film transistors (ZTO TFTs) using a dual-functional potassium superoxide precursor. Potassium cations in the potassium superoxide (KO 2 ) precursor act as carrier suppliers in the ZTO thin film to improve the carrier (electron) concentration, which allows the potassium-doped ZTO TFT to exhibit high mobility. The anions in the precursor exist as superoxide radicals that reduce oxygen vacancies during the formation of thin oxide film. Consequently, the KO 2 -treated ZTO TFTs exhibited improved mobility and reliability compared with pristine ZTO TFTs, with an increase in field effect mobility from 5.57 to 8.74 cm 2 /V s and a decrease in the threshold voltage shift from 7.18 to 3.85 V, after a positive bias temperature stress test conducted over 5000 s.