Liquid metal gallium-based printing of Cu-doped p-type Ga₂O₃ semiconductor and Ga₂O₃ homojunction diodes.

This article focuses on a novel liquid metal-based printing method to fabricate both n-type and p-type gallium oxide (Ga₂O₃) semiconductor films, addressing the longstanding challenge of achieving stable p-type doping in Ga₂O₃. By alloying gallium (Ga) with indium (In), tin (Sn), and copper (Cu) to form liquid metal alloys, ultrathin Ga₂O₃ and Cu-doped Ga₂O₃ films were selectively oxidized and printed via a van der Waals (vdW) exfoliation process at relatively low temperatures. The Cu doping induced p-type conductivity, confirmed by Hall effect measurements and electronic band structure analysis, enabling the fabrication of field-effect transistors (FETs) and homojunction p–n diodes with good electrical performance, stability, and Ohmic contacts achieved through air plasma treatment. This approach offers a cost-effective, scalable route for producing doped wide-bandgap semiconductor films with controllable thickness and doping, potentially advancing the manufacturing of electronic and optoelectronic devices.