2D InGaO_x Transistors Printed by Cabrera-Mott Oxidation of Liquid In-Ga Alloys

Next-generation flexible electronics will require low-temperature fabrication of high-mobility 2D semiconductors. Continuous liquid metal printing (CLMP) powered by Cabrera-Mott oxidation can support this goal by offering rapid (&lt; 3 s) processing of large-area (&gt; 20 cm²) 3 nm thick ‘2D’ layers of semiconducting oxides with high mobility. However, their high intrinsic carrier density demands new mechanisms of electrostatic control. We present a strategy for controlling transport in 2D In₂O₃ via doping with trace Ga inclusions (0.1–0.001 wt.%) in precursor metal alloys. We use these alloys to print indium gallium oxide (IGO) transistors at &lt; 200 °C with enhanced subthreshold slope and near 0 V turn on by reducing the electron concentrations 10-1000X with Ga-doping in the resultant channels (5–70 at.%). Printed 2D IGO transistors exhibit exceptional field effect mobility, with champion devices achieving up to 17 cm²/Vs and I_on/I_off up to 10⁶, with enhanced bias-stress stability over pure In₂O₃. Moreover, through a combination of experiments and finite element simulation, we demonstrate the synergy between 2D IGO and ultrathin high-k Al₂O₃ dielectrics for achieving low-voltage transistors with steep switching.<br/>We apply detailed materials characterization including XPS to quantify Ga doping and oxygen stoichiometry in the 2D IGO channels and EDS to analyze the Ga-rich surface oxide of the liquid precursor alloys. IGO films were investigated by XRD to evaluate the doping threshold for amorphization and by UV-Vis to analyze modulation of the optical bandgap and effects of quantum confinement. Collectively, these results illustrate the power of liquid metal alloy printing to control 2D semiconductor electrostatics and crystallinity for developing high performance flexible electronics and next-generation display technologies.