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

We report the fabrication of gallium oxide (GaOx) 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 GaOx thin films are investigated by complementary characterization analyses. The results indicate that solution-deposited GaOx experiences the elimination of organic residuals as well as the transformation of amorphous GaOx to crystalline GaOx with the increase in annealing temperature. High-quality GaOx 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 GaOx 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 GaOx achieved by PAD shows great potential for further low-cost and high-performance optoelectronic applications.