Twist Angle mapping in layered WS2 by Polarization-Resolved Second Harmonic Generation
Twist Angle mapping in layered WS2 by Polarization-Resolved Second Harmonic Generation
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DOI：
10.1038/s41598-019-50534-0
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发表时间：
2019-10-03
影响因子：
4.6
通讯作者：
Stratakis, Emmanuel
中科院分区：
文献类型：
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作者：
Psilodimitrakopoulos, Sotiris;Mouchliadis, Leonidas;Stratakis, Emmanuel
堆叠的原子级薄过渡金属二硫属化物（TMD）与单独的层相比表现出根本上新的物理性质。层之间的扭转角在调整这些特性中起着至关重要的作用。拥有一种能够提供高分辨率、大面积扭曲角映射的工具，在表征这种2D结构中将是非常重要的。在这里，我们使用偏振分辨二次谐波发生（P-SHG）成像显微镜快速映射的扭曲角在大面积的重叠WS 2堆叠层。我们的方法的鲁棒性在于在重叠区域中的SHG的强度和偏振测量的组合。这允许在该区域中的扭转角的精确测量和随后的逐像素映射。对于30度扭转角的特定情况，P-SHG能够对各个层进行成像。
Stacked atomically thin transition metal dichalcogenides (TMDs) exhibit fundamentally new physical properties compared to those of the individual layers. The twist angle between the layers plays a crucial role in tuning these properties. Having a tool that provides high-resolution, large area mapping of the twist angle, would be of great importance in the characterization of such 2D structures. Here we use polarization-resolved second harmonic generation (P-SHG) imaging microscopy to rapidly map the twist angle in large areas of overlapping WS2 stacked layers. The robustness of our methodology lies in the combination of both intensity and polarization measurements of SHG in the overlapping region. This allows the accurate measurement and consequent pixel-by-pixel mapping of the twist angle in this area. For the specific case of 30 degrees twist angle, P-SHG enables imaging of individual layers.