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 squeezing technique with conventional lithography to obtain a β-Ga2O3 layer with a controllable thickness and shape. Our synthetic method has the potential to overcome the limitations of conventional β-Ga2O3 growth methods, paving a path for applications in UWBG-based (opto-)electronics with a high throughput in a cost-effective manner.
Large-scale synthesis of atomically thin ultrawide bandgap β-Ga2O3 using a liquid gallium squeezing technique
Hyunik Park, Yongha Choi, Sujung Yang, Jinho Bae, Jihyun Kim; Large-scale synthesis of atomically thin ultrawide bandgap β-Ga2O3 using a liquid gallium squeezing technique. J. Vac. Sci. Technol. A 1 May 2021; 39 (3): 033409. https://doi.org/10.1116/6.0000927
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