Cui Xueping, Sun Lulu, Zeng Yan, Hao Yang, Liu Yanpeng, Wang Dong, Yi Yuanping, Loh Kian Ping, Zheng Jian, Liu Yunqi
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, CAS, Beijing 100190, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Nano Lett. 2020 Aug 12;20(8):6059-6066. doi: 10.1021/acs.nanolett.0c02098. Epub 2020 Jul 9.
Recently, twisted two-dimensional (2D) bilayers have attracted intense interest due to the emergence of exotic physics in moiré superlattices arising from strong interactions between electrons in the two misaligned lattices. Accurate determination and control of crystallographic orientation is vital to construct twisted 2D bilayers. Here, we demonstrate a very simple method to visualize crystallographic orientation in various 2D crystals by directly imaging -tritriacontane crystallites epitaxially grown on 2D crystals using an ordinary optical microscope. The specific orientation of the molecular assembly allows the lattice orientation of the underlying 2D crystals to be determined with a high precision using an optical microscope. When tested on a 2D bilayer comprising staggered stacked MoS crystals, the twist angle can also be determined accurately. Our findings offer a nondestructive method for determining the lattice structure of 2D crystals and their bilayers and can also be a metrology tool for establishing large-area surface crystalline order.
最近，扭曲的二维（2D）双层由于两个错位晶格中电子之间的强相互作用导致的莫尔超晶格中出现奇异物理现象而引起了广泛关注。精确确定和控制晶体取向对于构建扭曲的二维双层至关重要。在这里，我们展示了一种非常简单的方法，通过使用普通光学显微镜直接成像在二维晶体上外延生长的三十四烷微晶，来可视化各种二维晶体中的晶体取向。分子组装的特定取向使得可以使用光学显微镜高精度地确定底层二维晶体的晶格取向。当在由交错堆叠的MoS晶体组成的二维双层上进行测试时，扭转角也可以准确确定。我们的发现提供了一种用于确定二维晶体及其双层晶格结构的无损方法，并且还可以成为建立大面积表面晶体有序性的计量工具。
