Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom.
Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
Nano Lett. 2017 Sep 13;17(9):5502-5507. doi: 10.1021/acs.nanolett.7b02192. Epub 2017 Aug 11.
The edges of 2D materials show novel electronic, magnetic, and optical properties, especially when reduced to nanoribbon widths. Therefore, methods to create atomically flat edges in 2D materials are essential for future exploitation. Atomically flat edges in 2D materials are found after brittle fracture or when electrically biasing, but a simple scalable approach for creating atomically flat periodic edges in monolayer 2D transition metal dichalcogenides has yet to be realized. Here, we show how heating monolayer MoS to 800 °C in vacuum produces atomically flat Mo terminated zigzag edges in nanoribbons. We study this at the atomic level using an ultrastable in situ heating holder in an aberration-corrected transmission electron microscope and discriminating Mo from S at the edge, revealing unique Mo terminations for all zigzag orientations that remain stable and atomically flat when cooling back to room temperature. Highly faceted MoS nanoribbon constrictions are produced with Mo rich edge structures that have theoretically predicted spin separated transport channels, which are promising for spin logic applications.
二维材料的边缘呈现出新颖的电子、磁性和光学性质，尤其是在缩减至纳米带宽度时。因此，开发二维材料原子级平整边缘的方法至关重要。在脆性断裂或电偏置时，可以在二维材料中找到原子级平整的边缘，但尚未实现一种简单且可扩展的方法，用于在单层二维过渡金属二卤化物中创建原子级平整的周期性边缘。在这里，我们展示了如何在真空中将单层 MoS 加热至 800°C，从而在纳米带中产生原子级平整的 Mo 终止的锯齿形边缘。我们使用具有原子分辨率的原位加热holder 在经过像差校正的透射电子显微镜中对此进行了研究，并在边缘处对 Mo 和 S 进行了区分，揭示了所有锯齿形取向的独特 Mo 终止，这些终止在冷却回室温时保持稳定且原子级平整。通过富 Mo 的边缘结构制造出具有高度多面的 MoS 纳米带限制结构，这些结构具有理论预测的自旋分离输运通道，有望用于自旋逻辑应用。
