Significant Performance Improvement of Solution-Processed Metal Oxide Transistors by Ligand Dissociation through Coupled Temperature–Time Treatment of Aqueous Precursors

We report on significant performance enhancements of thin-film transistors based on indium oxide thin-film prepared from aqueous precursor solution. To achieve this improvement, the aqueous indium nitrate solutions were aged under different temperatures and times before spin-coating the solution onto a substrate for the formation of the metal oxide layer. It was found that the performance of transistors depends significantly on the precursor’s treatment conditions; a device prepared from a precursor solution treated at optimal conditions exhibited a charge carrier mobility of 23.53 cm2 V–1 s–1, which is more than 35 times higher than that (0.64 cm2 V–1 s–1) of one prepared from an untreated precursor solution. Electrical switching characteristic of the optimized transistor was also evaluated using a load-type inverter constructed by connecting the transistor to an appropriate load resistor. The clear switching response to a 500 Hz square-type input was observed with the inverter, which can be operated up to 1 kHz