Large-scale synthesis of atomically thin ultrawide bandgap β-Ga2O3 using a liquid gallium squeezing technique

β-Ga2O3, an emerging ultrawide bandgap (UWBG) semiconductor, offers promising properties for next-generation power electronics, chemical sensors, and solar-blind optoelectronics. Scaling down of β-Ga2O3 to the atomic level affords the advantages of two-dimensional (2D) materials, while maintaining the inherent properties of the parent bulk counterpart. Here, we demonstrate a simple approach to synthesize ultrathin millimeter-size β-Ga2O3 sheets using a liquid gallium squeezing technique. The GaOx nanolayer produced by stamping liquid gallium under the Cabrera–Mott oxidation was converted into few-atom-thick β-Ga2O3 via thermal annealing under atmospheric conditions. This approach was also applied to various substrates such as SiO2, Si, graphene, quartz, and sapphire to heteroepitaxially synthesize 2D β-Ga2O3 on a target substrate. Finally, we propose a patterning strategy combining the s…