Vapor phase growth of two-dimensional Cr₂O₃ nanosheets with non-equilibrium charge conduction

Two-dimensional(2D) materials, especially 2D transition metal oxides (TMOs), have garnered significant research attention due to their unique physical and chemical properties and vast potential applications in electronics, optoelectronics, magneto electronics, and energy storage. However, synthesizing 2D TMOs remains a major challenge due to their non-layered lattice structure and the high temperatures required for synthesis. In this study, we report the chemical vapor deposition-based synthesis of high-quality 2D Cr₂O₃ single-crystal nanosheets and investigate their structure and electrical properties. By controlling the growth temperature and carrier gas, we successfully obtained Cr₂O₃ nanosheets with lateral dimensions up to 30 μm and a minimum thickness of 4.7 nm. Optical studies, X-ray diffraction, atomic force microscopy, and transmission electron microscopy confirm that the resulting nanosheets are high-quality single crystals. Electrical measurements reveal that charge transport in Cr₂O₃ devices is influenced by both Schottky emission and Poole-Frenkel emission, leading to a non-equilibrium charge conduction state. This systematic synthesis approach provides a reliable route for fabricating 2D TMO single crystals with controlled thickness and offers a platform for investigating charge transfer at electrode-dielectric interfaces, as well as for the design of novel electronic materials and catalysts.