石墨烯/二硒化钨异质结中的层间相互作用：堆叠次序与角度

通信作者

李海 & 黄晓 

南京工业大学柔性电子重点实验室与先进材料研究院

研究背景和亮点

近年来，由两种或多种二维纳米薄片组装形成的二维范德华异质结（vdWH）展现出许多不同于单种二维纳米薄片的新奇物理性质和现象，迅速成为化学、材料、微电子和光电器件领域的研究热点[1-5]。基于vdWH材料的器件具有传统器件未具备的超薄、柔性、透明等特点，在新型微纳光电子器件方面具有良好的应用前景[6-7]。

随着研究的深入，人们发现vdWH中不同二维纳米薄片之间的相互作用对其性能具有较大影响[4,7-9]。拉曼光谱法具有无损、快速等优点，是表征异质结层间相互作用的主要方法之一[8-10]。南京工业大学李海教授和黄晓教授课题组利用超低波拉曼光谱仪和原子力显微镜（AFM），研究了石墨烯和二硒化钨（WSe₂）范德华异质结中纳米薄片的堆叠次序和角度对其层间相互作用的影响[11]。研究表明，在Graphene/WSe₂和WSe₂/Graphene异质结的超低波拉曼光谱中，WSe₂的固有呼吸峰会随石墨烯层厚的增加而逐渐红移。当石墨烯增加到一定的厚度时，观察到新的呼吸峰且其随石墨烯厚度的增加也发生红移（图1）。此外，石墨烯和WSe₂的堆叠次序对异质结中的层间相互作用产生较大影响。如图1(c,d)所示，相对于WSe₂/Graphene异质结的超低波呼吸峰而言，Graphene/WSe₂异质结的超低波呼吸峰发生了明显的红移。他们还进一步研究了异质结中纳米薄片的堆叠角度对其层间相互作用的影响（图2）。结果表明，层间相互作用随堆叠角度不同并未发生明显的变化，说明WSe₂和石墨烯纳米薄片之间的层间相互作用对堆叠角度并不敏感。

参考文献

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文献链接

Yue Liu, Hao Zhang, Yu Zhou, Feirong Ran, Weihao Zhao, Lin Wang, Chengjie Pei, Jindong Zhang, Xiao Huang, and Hai Li, Probing interlayer interactions in WSe₂-graphene heterostructures by ultralow frequency Raman spectroscopy, Front. Phys. 14(1), 13607 (2019)