Doping of Indium Oxide Semiconductor Film Prepared Using an Environmentally Friendly Aqueous Solution Process with Sub-1% Molybdenum to Improve Device Performance and Stability

Amorphous In2O3 is an emerging metal oxide semiconductor that is used widely because of its high mobility and solution processability. Fully aqueous processing methods without chemical additives and to avoid organic solvents are being actively developed. Issues related to charge trapping, such as high threshold voltage and low bias stress stability, can hinder the applications of these thin films. In this work, solution-processed In2O3 layers doped with MoO3 were prepared to study the tunability of the electrical performance characteristics such as charge carrier mobility, threshold voltage, and subthreshold swing. The doping was found to sufficiently change the oxygen content of the film while only minimally affect the film morphology. Using the optimal 0.49 mol % MoO3 content, the threshold voltage of the device with pristine In2O3 was reduced from 10 to 4 V, and bias stability improved by more than 50% under negative voltages and by 25% under positive voltages. A resistive load inverter was fabricated to demonstrate device applicability. This study demonstrates the tunability of metal oxide thin films prepared by an aqueous route with sub-1% doping.