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 cm(2) V-1 s(-1), which is more than 35 times higher than that (0.64 cm(2) 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.