Fully Solution-Processed\nLow-Voltage Aqueous In₂O₃ Thin-Film Transistors\nUsing an Ultrathin ZrO_<i>x</i> Dielectric

Abstract

We\nreported here “aqueous-route” fabrication of In₂O₃ thin-film transistors (TFTs) using an ultrathin\nsolution-processed ZrO_<i>x</i> dielectric thin\nfilm. The formation and properties of In₂O₃ thin\nfilms under various annealing temperatures were intensively examined\nby thermogravimetric analysis, Fourier transform infrared spectroscopy,\nand atomic force microscopy. The solution-processed ZrO_<i>x</i> thin film followed by sequential UV/ozone treatment\nand low-temperature thermal-annealing processes showed an amorphous\nstructure, a low leakage-current density (∼1 × 10^–9 A/cm² at 2 MV/cm), and a high breakdown\nelectric field (∼7.2 MV/cm). On the basis of its implementation\nas the gate insulator, the In₂O₃ TFTs based\non ZrO_<i>x</i> annealed at 250 °C exhibit\nan on/off current ratio larger than 10⁷, a field-effect\nmobility of 23.6 cm²/V·s, a subthreshold swing of\n90 mV/decade, a threshold voltage of 0.13 V, and high stability. These\npromising properties were obtained at a low operating voltage of 1.5\nV. These results suggest that “aqueous-route” In₂O₃ TFTs based on a solution-processed ZrO_<i>x</i> dielectric could potentially be used for low-cost,\nlow-temperature-processing, high-performance, and flexible devices.