Formation of metal vacancy arrays in coalesced WS2 monolayer films
Formation of metal vacancy arrays in coalesced WS2 monolayer films
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DOI：
10.1088/2053-1583/abc905
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发表时间：
2020-12
期刊：
影响因子：
5.5
通讯作者：
D. Reifsnyder Hickey;D. Yilmaz;M. Chubarov;S. Bachu;Tanushree H Choudhury;L. Miao;Chenhao Qian;J. Redwing;A. V. van Duin;N. Alem
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作者：
D. Reifsnyder Hickey;D. Yilmaz;M. Chubarov;S. Bachu;Tanushree H Choudhury;L. Miao;Chenhao Qian;J. Redwing;A. V. van Duin;N. Alem
缺陷对晶体的电子和物理性质有深远的影响。对于二维（2D）材料，已经报道了许多内在点缺陷，但它们的起源仍有待了解。利用扫描透射电子显微镜成像，本研究发现了w空位缺陷的各种线性阵列，这些缺陷可以在聚结单层WS2晶体生长的背景下解释。原子尺度的模拟结果表明，空位阵列是由体积较大的气相前驱体在狭窄的生长边缘处的空间位阻引起的，而边缘距离的增加会导致各种完整和缺陷的生长模式，这是由蓝宝石衬底和邻近生长边缘的催化效应之间的竞争驱动的。因此，我们假设阵列是由组合生长模式产生的，而组合生长模式直接由薄膜聚结引起。这里绘制的连接将指导未来的合成和处理策略，以利用二维单层中缺陷的工程潜力。
Defects have a profound impact on the electronic and physical properties of crystals. For two-dimensional (2D) materials, many intrinsic point defects have been reported, but much remains to be understood about their origin. Using scanning transmission electron microscopy imaging, this study discovers various linear arrays of W-vacancy defects that are explained in the context of the crystal growth of coalesced, monolayer WS2. Atomistic-scale simulations show that vacancy arrays can result from steric hindrance of bulky gas-phase precursors at narrowly separated growth edges, and that increasing the edge separation leads to various intact and defective growth modes, which are driven by competition between the catalytic effects of the sapphire substrate and neighboring growth edge. Therefore, we hypothesize that the arrays result from combined growth modes, which directly result from film coalescence. The connections drawn here will guide future synthetic and processing strategies to harness the engineering potential of defects in 2D monolayers.