Tailoring Solid Phase Crystallization for Tunable Electronic Transport in Liquid Metal Printed 2D Oxides

ABSTRACT 2D metal oxide semiconductors are promising wide band gap materials due to their high electron mobility and optical transparency, making them of significant interest for flexible transparent electronics. These high‐performance, ultrathin (∼3 nm) semiconductors can be fabricated with vacuum‐free Cabrera‐Mott oxidation of the surface of liquid metals at the wafer‐scale at ultralow temperatures (<200°C), but harnessing this process requires precise nanoscale engineering of their electrostatic properties. Here, we report for the first time the tailoring of the solid phase crystallization of 2D InO x to enhance device performance via controlled orientation. Transmission electron microscopy and X‐ray scattering studies reveal that low‐temperature fabrication yields large, plate‐like grains with substrate‐aligned, preferential {400} texture, whereas higher processing temperatures result in mixed {222}/{400} orientations. Thin film transistors fabricated at just 175°C from the preferentially {400} oriented films exhibit over 10× higher performance than those with mixed {222}/{400} oriented films, with linear mobility as high as 33.8 cm 2 /Vs and on/off ratios greater than 10 6 , outperforming other vacuum‐free, printed metal oxides. These results reveal the unique opportunity for liquid metal interfaces to grow single‐orientation high‐mobility oxide semiconductors at low temperatures compatible with flexible polymer substrates.