STEM imaging artifacts with three-fold astigmatism in monolayer transition metal dichalcogenides
STEM imaging artifacts with three-fold astigmatism in monolayer transition metal dichalcogenides
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DOI：
10.1063/5.0011782
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发表时间：
2020-06-15
影响因子：
4
通讯作者：
Suenaga, Kazu
中科院分区：
文献类型：
--
作者：
Hong, Jinhua;Koshino, Masanori;Suenaga, Kazu
像差校正扫描透射电子显微镜已被证明是探测二维材料中原子缺陷和局部电子态的通用工具。然而，探针的残余像差可能会引起与完美成像的相当大的偏差，特别是在多相过渡金属二硫属化物中。在这里，我们澄清了误导性的成像伪影相反的子域在单层二硫化钼通过图像模拟和实验在平面内旋转系列。这种非蜂窝状成像伪影原来是由探头残余三倍像散和局部样品倾斜或波动引起的。我们的研究结果表明，直接STEM成像应谨慎对待，以实现准确的相位分配。
Aberration-corrected scanning transmission electron microscopy has been demonstrated as a versatile tool to probe the atomic defects and local electronic states in 2D materials. However, the residual aberration of the probe may give rise to considerable deviations from the perfect imaging, especially in polyphase transition metal dichalcogenides. Here, we clarify the misleading imaging artifact of opposite subdomains in monolayer MoS2 through both image simulations and experimental in-plane rotation series. This non-honeycomb imaging artifact turns out to be caused by both probe residual threefold astigmatism and local sample tilt or fluctuation. Our results suggest that the direct STEM imaging should be cautiously treated to achieve accurate phase assignment.