2D Amorphous Homojunction Transistors Exfoliated from Liquid Metals

Abstract Ultrathin 2D metal oxides are a high‐performance class of transparent conducting materials capable of overcoming the traditional limitations of inorganic flexible electronics. The low temperature, thermodynamically favorable synthesis of 2D oxides at liquid metal interfaces offers the potential for printing these materials over large areas at unprecedented speeds with sub‐nanometer scale precision. However, these native oxides are sub‐stoichiometric and highly conductive, so new strategies are needed that can precisely engineer the electrostatics and enhance stability. In this work, the crystalline vs. amorphous phase of 2D oxides is engineered via alloying of ternary In 1‐y Sn y O x and ultralow deposition temperatures (120–160 °C) are afforded by In‐Sn eutectics. This approach is extended to rapid assembly of nanoscale (3–5 nm per layer) vertical 2D homojunctions with electrostatically favorable grading from high density of states front channels to lower density of states back‐channels. Detailed materials characterization reveals how this platform enhances electron mobility while improving resilience under bias‐stress in metal oxide transistors. Devices based on amorphous 2D oxide homojunctions with high‐k sol‐gel ZrO x dielectrics achieve excellent electron mobility (30 cm 2 /V·s), steep switching (SS of 100 mV dec −1 ), I on/off of 10 7 and 10X reduced bias‐stress shifts, presenting an ideal strategy for high‐performance flexible oxide electronics.