Engineering Vertically‐Growing V ₂ O ₃ Nanosheets and Unveiling Their Novel Properties

ABSTRACT Two‐dimensional (2D) transition metal oxides (TMOs) have attracted considerable interest owing to their exceptional electronic, magnetic, and catalytic properties. Among them, V ₂ O ₃ is particularly intriguing due to its well‐known metal‐insulator transition and correlated electron behavior. However, the challenge in controllably synthesizing ultrathin, high‐quality V ₂ O ₃ single crystals, stemming from its unique crystal structure and complex phase stability, has hindered a fundamental understanding of its electronic and magnetic properties. In this work, we demonstrate a Ge‐assisted chemical vapor deposition (CVD) strategy that enables vertical and free‐standing growth of high‐quality V ₂ O ₃ nanosheets. This method not only facilitates out‐of‐plane growth but also simplifies post‐processing steps. The as‐synthesized nanosheets attain thicknesses as thin as 0.72 nm. Structural characterization via x‐ray diffraction (XRD), transmission electron microscopy (TEM), and high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) confirms their high crystallinity and phase purity. Electrical characterization reveals a thickness‐dependent metallic behavior at room temperature and a pronounced metal‐insulator transition upon cooling. Moreover, magnetization measurements (M‐H) indicate emerging ferromagnetic properties around 140 K. This study provides a reliable platform based on thickness‐controlled V ₂ O ₃ nanosheets for exploring correlated electronic and magnetic phenomena in the 2D limit and for developing advanced devices.