Optimizing the Performance of Printed Indium Oxide Thin-Film Transistors through Gallium Incorporation

The present study explores the optimization of printed electrolyte-gated field-effect transistors (EGTs) with an indium oxide (In2O3-x) channel by introducing gallium into the In2O3-x material. Indium oxide (In2O3-x) and indium gallium oxide (IGO) nanoparticles are synthesized and formulated into water-based functional inks for printing In2O3-x and IGO thin films at room temperature. These thin films are characterized and employed as the semiconductor channel for EGTs. Gallium incorporation shifts the EGT threshold voltage from 0.2 to 0.5 V and reduces the off-current by up to three orders of magnitude depending on the gallium concentration. Shifting the threshold voltage toward positive values while reducing off-currents is essential for designing logic gates in various topologies, such as transistor-resistor logic and transistor-transistor logic, as demonstrated in inverter structures. Prepared inverters using IGO exhibit slightly higher gain and lower power consumption.