Amorphous bilayer TiO2–InGaZnO thin film transistors with low drive voltage

•Low-voltage-driven (<2 V) TiO2–InGaZnO TFT has low turn-on voltage of 0.45 V.•TiO2–IGZO TFT features small gate swing of 174 mV/decade and high mobility of 19 cm2/V s.•The incorporation of TiO2 semiconductor improves device mobility and gate swing of IGZO TFT.

This paper describes a high-performance thin-film transistor (TFT) fabricated using TiO2 and InGaZnO semiconducting layers. Favorable transistor characteristics, including a low threshold voltage of 0.45 V, a small subthreshold swing of 174 mV/decade, and a high field effect mobility of 19 cm2/V s at a low drive voltage of <2 V, were achieved. This favorable performance mainly resulted from the combined effect of the high-dielectric-constant gate dielectric and the TiO2–InGaZnO active semiconductor bilayer, which reduced the operating voltage, enhanced the device mobility, and improved the transistor gate swing. This TiO2–InGaZnO TFT exhibits great potential for future high-speed and high-resolution display applications.