Continuous large area oxide printing from liquid metals

Amorphous metal oxides (AMO) are a class of semiconducting materials that show promising application in optoelectronics because of their high carrier mobility and optical transparency. By alloying with other metallic species and regulating the oxygen vacancies, the carrier mobility, and the optical bandgap energy of AMOs can be modified. This customizability not only broadens the operating window of AMOs in optoelectronics but also further enables other applications, such as digital memory devices and thin-film-transistors. Typically, AMO thin films are obtained by conventional chemical or physical vapor deposition; however, these processes generally require undesirable toxic gas precursors, a vacuum environment, and a long processing time. Gallium-based liquid metals (LMs) – a class of metals that exist as liquid at or near room temperature – naturally forms an ultrathin layer of AMO (~3nm) on their surface under ambient conditions. Herein, we propose a method to harness this feature to continuously deposit gallium oxide (GaOx) and gallium indium oxide (GaInOx) traces with their host LMs at or near ambient conditions.