Transition metal dichalcogenides (TMD), which is composed of a transition metal atom and chalcogen ion atoms, usually form vacancies based on the knock-on threshold of each atom. In particular, when electron beam is irradiated on a monolayer TMD such as MoS 2 and WS 2 , S vacancies are formed preferentially, and they are aligned linearly to constitute line defects. And then, a hole is formed at the point where the successively formed line defects collide, and metal clusters are also formed at the edge of the hole. This study reports a process in which the line defects formed in a monolayer WS 2 sheet expends into holes. Here, the process in which the W cluster, which always occurs at the edge of the formed hole, goes through a uniform intermediate phase is explained based on the line defects and the formation behavior of the hole. Further investigation confirms the atomic structure of the intermediate phase using annular dark field scanning transition electron microscopy (ADF-STEM) and image simulation.

中文翻译：

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单层WS2中从线缺陷到原子簇的顺序转换

过渡金属二硫属化物 (TMD) 由过渡金属原子和硫属元素离子原子组成，通常根据每个原子的碰撞阈值形成空位。特别是，当电子束照射在单层TMD如MoS 2 和WS 2 上时，S空位优先形成，并且它们线性排列而构成线缺陷。然后，在连续形成的线缺陷碰撞的点形成孔，在孔的边缘也形成金属簇。该研究报告了在单层 WS 2 片中形成的线缺陷扩展到孔中的过程。在此，基于线缺陷和孔的形成行为来解释总是出现在形成孔边缘的W簇经过均匀中间相的过程。