Polymer-Assisted Deposition of Gallium Oxide for Thin-Film Transistor Applications

We report the fabrication of gallium oxide (GaO_x) thin films by a novel polymer-assisted deposition (PAD) method. The influence and mechanism of postannealing temperature (200–800 °C) on the formation and properties of GaO_x thin films are investigated by complementary characterization analyses. The results indicate that solution-deposited GaO_x experiences the elimination of organic residuals as well as the transformation of amorphous GaO_x to crystalline GaO_x with the increase in annealing temperature. High-quality GaO_x could be achieved with a smooth surface, wide band gap, and decent dielectric performance. Moreover, the solution-processed In₂O₃ thin-film transistors based on optimized GaO_x dielectrics demonstrate outstanding electrical performance, including a low operating voltage of 5 V, a mobility of 3.09 cm² V^–1 s^–1, an on/off current ratio of 1.8 × 10⁵, and a subthreshold swing of 0.18 V dec^–1. Our study suggests that GaO_x achieved by PAD shows great potential for further low-cost and high-performance optoelectronic applications.