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 (I_on/I_off), and large, negative threshold voltages (V_TH), 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 V_TH (3.2 V), high saturation current (1.1 × 10^–4 A), large on/off current ratio (> 10⁸), 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-κ HfO_x thin films are employed as the gate dielectric, their electron mobility and V_TH can be further improved to 5.30 cm²/(V·s) and 0.9 V, respectively, which demonstrates the promising prospect of these Mg-doped In₂O₃ NF networks for highperformance, large-scale, and low-power electronics.