Department of Chemistry, Columbia University, New York, NY 10027, USA.
Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA.
Science. 2020 Feb 21;367(6480):903-906. doi: 10.1126/science.aba1416.
Two-dimensional materials from layered van der Waals (vdW) crystals hold great promise for electronic, optoelectronic, and quantum devices, but technological implementation will be hampered by the lack of high-throughput techniques for exfoliating single-crystal monolayers with sufficient size and high quality. Here, we report a facile method to disassemble vdW single crystals layer by layer into monolayers with near-unity yield and with dimensions limited only by bulk crystal sizes. The macroscopic monolayers are comparable in quality to microscopic monolayers from conventional Scotch tape exfoliation. The monolayers can be assembled into macroscopic artificial structures, including transition metal dichalcogenide multilayers with broken inversion symmetry and substantially enhanced nonlinear optical response. This approach takes us one step closer to mass production of macroscopic monolayers and bulk-like artificial materials with controllable properties.
二维材料来自层状范德华（vdW）晶体，有望用于电子、光电和量子器件，但由于缺乏高通量技术来剥离具有足够尺寸和高质量的单晶单层，其技术实现将受到阻碍。在这里，我们报告了一种将 vdW 单晶逐层分离成单层的简便方法，其单层的产率接近 100%，尺寸仅受块状晶体尺寸的限制。宏观单层的质量与传统 Scotch 胶带剥离的微观单层相当。这些单层可以组装成宏观人工结构，包括具有非中心对称和非线性光学响应增强的过渡金属二卤化物多层结构。这种方法使我们更接近于大规模生产宏观单层和具有可控性能的块状人工材料。
