Department of Physics and Astronomy, Sejong University, Seoul 05006, Korea.
Nanoscale. 2019 Jan 3;11(2):431-436. doi: 10.1039/c8nr09258c.
Two-dimensional (2D) transition metal dichalcogenides with van der Waals gaps have attracted much attention due to their peculiarly distinctive physical properties from their bulk counterparts. Among them, vanadium diselenide (VSe2) has been considered to be a promising candidate for future spintronic devices, as room temperature ferromagnetism was reported recently. However, detailed crystallography and properties of VSe2 nanosheets have been less explored. Here, we report the atomistic real-space observation of the van der Waals layered structure of VSe2 for the first time. Furthermore, simply by controlling the carrier gas flow rate, a morphological variation of the surface area and thickness of VSe2 nanosheets was observed. The room temperature ferromagnetic feature of single VSe2 nanosheets was also revealed by magnetic force microscopy measurements. Our findings will play a significant role in the research of intrinsic 2D ferromagnetic materials.
二维（2D）过渡金属二卤族化合物具有范德华间隙，由于其具有与体材料截然不同的独特物理性质而备受关注。其中，二硒化钒（VSe2）被认为是未来自旋电子器件的有前途的候选材料，因为最近报道了室温铁磁性。然而，VSe2 纳米片的详细晶体学和性质尚未得到充分探索。在这里，我们首次报告了 VSe2 的范德华层状结构的原子级实空间观察。此外，通过简单地控制载气流速，观察到 VSe2 纳米片的表面积和厚度的形态变化。通过磁力显微镜测量还揭示了单个 VSe2 纳米片的室温铁磁性特征。我们的发现将在本征 2D 铁磁材料的研究中发挥重要作用。
