Abstract: The homojunction based on Ti₃C₂T_x MXene-doped In₂O₃ and indium oxide as the channel layer is realized in high-performance metal oxide thin film transistors (TFTs). Doping of MXene into In₂O₃ results in n-type semiconductor behavior, realizing tunable work function of In₂O₃ from 5.11 to 4.79 eV as MXene content increases from 0 to 2 wt.%. MXene-doped In₂O₃-based homojunction TFT presents optimal performance with electron mobilities of greater than 27.10 cm²/(V s) at 240 °C, far exceeding the maximum mobility of 3.91 cm²/(V s) for single-layer In₂O₃ TFTs. The improved performance originates from boosting of a two-dimensional electron gas (2DEG) formed at carefully engineered In₂O₃/MXene-doped In₂O₃ oxide homojunction interface. Besides, the transformation in conduction mechanism leads to better stability of MXene-doped In₂O₃ homojunction devices compared to undoped bilayer In₂O₃. Low-frequency noise further illustrates that doping MXene into In₂O₃ helps to reduce the device trap density, demonstrating excellent electrical performance. A resistor-loaded unipolar inverter based on In₂O₃/0.5% MXene-In₂O₃ TFT has demonstrated full swing characteristics and a high gain of 13. The effective doping of MXene into constructed homojunction TFTs not only contributes to improved stability, but also provides an effective strategy for designing novel homojunction TFTs for low-cost oxide-based electronics.

Key words: MXene-doped In₂O₃, Homojunction, 2D electron gases, Thin film transistor, Low frequency noise