Impact of Humidity on the Performance and Stability of Solution-Processed Copper Oxide Transistors

Abstract

We found that during spin-coating and annealing processes, the ambient humidity can have obvious impact on the characteristics of p-channel copper oxide thin-film transistors (TFTs). We studied such impact in great details along with the device operational stability. A dry deposition atmosphere (relative humidity, ${\mathrm {RH}} \le20$ %) is necessary for the best device performance, including a hole mobility of 0.1 cm $^{{2}}\,\,\text{V}^{{-1}}\,\,\text{s}^{{-1}}$ , an on/off current ratio of $> 10^{{4}}$ , and high operational stability (< 2 V threshold voltage shift after 5.5 h of bias stress), attributable to residues with fewer hydroxide defects. These findings offer a clear inspiration for achieving highly stable and reproducible p-channel oxide TFTs through a low-cost solution process.