New Mechanical Exfoliation Technique for Preparing Large Area 2D Materials and Special Structures

Mechanical exfoliation method has been widely used to study the intrinsic properties of 2D materials. Even though the exfoliated 2D materials show high quality, the size of monolayer samples are usually quite small, which has limited the investigation progress of 2D materials. Recently, we developed a new mechanical exfoliation technique for preparing large area and high quality 2D materials^[1]. Many monolayer 2D materials with milimeter to centermeter size have been successfully exfoliated through this method, including graphene, TMDCs et al. The key of this technique is to enhance the van der Waals interaction between the layered materials and the substrates, which can be realized by optimizing the exfoliation process, such as substrate types, temperature and vacuum. Besides, some special structures (like bubble and wrinkle) can be prepared by using different parameters. Therefore, many unique properties can be observed on these structures, e.g., standing wave induced Raman oscillation was first discovered on the exfoliated graphene bubbles^[2]. The new mechanical technique will show great potential for exploring new properties of 2D materials.


References
[1] Y. Huang, et al., ACS nano, 2015, 9, 10612.
[2] Y. Huang, et al., Phys. Rev. Lett., 2018, 120, 186104.