National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory for Nanotechnology, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
Department of Physics and Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen, China.
Nature. 2023 Sep;621(7979):499-505. doi: 10.1038/s41586-023-06404-x. Epub 2023 Sep 6.
Two-dimensional (2D) van der Waals (vdW) heterostructures have attracted considerable attention in recent years. The most widely used method of fabrication is to stack mechanically exfoliated micrometre-sized flakes, but this process is not scalable for practical applications. Despite thousands of 2D materials being created, using various stacking combinations, hardly any large 2D superconductors can be stacked intact into vdW heterostructures, greatly restricting the applications for such devices. Here we report a high-to-low temperature strategy for controllably growing stacks of multiple-layered vdW superconductor heterostructure (vdWSH) films at a wafer scale. The number of layers of 2D superconductors in the vdWSHs can be precisely controlled, and we have successfully grown 27 double-block, 15 triple-block, 5 four-block and 3 five-block vdWSH films (where one block represents one 2D material). Morphological, spectroscopic and atomic-scale structural analyses reveal the presence of parallel, clean and atomically sharp vdW interfaces on a large scale, with very little contamination between neighbouring layers. The intact vdW interfaces allow us to achieve proximity-induced superconductivity and superconducting Josephson junctions on a centimetre scale. Our process for making multiple-layered vdWSHs can easily be generalized to other situations involving 2D materials, potentially accelerating the design of next-generation functional devices and applications.
二维（2D）范德华（vdW）异质结构近年来引起了广泛关注。最广泛使用的制造方法是堆叠机械剥离的微米级薄片，但该工艺不适用于实际应用。尽管已经创造了数千种二维材料，并采用了各种堆叠组合，但几乎没有任何大型二维超导体可以完整堆叠成 vdW 异质结构，这极大地限制了此类器件的应用。在这里，我们报告了一种在晶圆尺度上可控生长多层 vdW 超导体异质结构（vdWSH）薄膜的高低温策略。vdWSH 中 2D 超导体的层数可以精确控制，我们已经成功生长了 27 个双层、15 个三层、5 个四层和 3 个五层 vdWSH 薄膜（一个块代表一种 2D 材料）。形貌、光谱和原子尺度结构分析表明，在很大范围内存在平行、清洁和原子级锐利的 vdW 界面，相邻层之间几乎没有污染。完整的 vdW 界面使我们能够在厘米尺度上实现近邻诱导超导和超导约瑟夫森结。我们制造多层 vdWSH 的方法可以很容易地推广到涉及二维材料的其他情况，从而有可能加速下一代功能器件和应用的设计。
