High performance In₂O₃ thin film transistors using chemically derived aluminum oxide dielectric

We report high performance solution-deposited indium oxide thin film transistors with field-effect mobility of 127 cm²/Vs and an I_on/I_off ratio of 10⁶. This excellent performance is achieved by controlling the hydroxyl group content in chemically derived aluminum oxide (AlO_x) thin-film dielectrics. The AlO_x films annealed in the temperature range of 250–350 °C showed higher amount of Al-OH groups compared to the films annealed at 500 °C, and correspondingly higher mobility. It is proposed that the presence of Al-OH groups at the AlO_x surface facilitates unintentional Al-doping and efficient oxidation of the indium oxide channel layer, leading to improved device performance.