High-performance enhancement-mode thin-film transistors based on Mg-doped In2O3 nanofiber networks

Although In2O3 nanofibers （NFs） are well-known candidates as active materials for next-generation, low-cost electronics, these NF based devices still suffer from high leakage current, insufficient on-off current ratios （Ion/Ioff）, and large, negative threshold voltages （VTH）, leading to poor device performance, parasitic energy consumption, and rather complicated circuit design. Here, instead of the conventional surface modification of In2O3 NFs, we present a one-step electrospinning process （i.e., without hot-press） to obtain controllable Mg-doped In2O3 NF networks to achieve high-performance enhancement-mode thin-film transistors （TFTs）. By simply adjusting the Mg doping concentration, the device performance can be manipulated precisely. For the optimal doping concentration of 2 mol%, the devices exhibit a small VTH （3.2 V）, high saturation current （1.1 × 10^-4 A）, large on/off current ratio （〉 10^8）, and respectable peak carrier mobility （2.04 cm2/（V.s））, corresponding to one of the best device performances among all 1D metal-oxide NFs based devices reported so far. When high-K HfOx thin films are employed as the gate dielectric, their electron mobility and VTH can be further improved to 5.30 cm^2/（V.s） and 0.9 V, respectivel）, which demonstrates the promising prospect of these Mg-doped In2O3 NF networks for high- performance, large-scale, and low-power electronics.