Universal mechanical exfoliation of large-area 2D crystals

• DOI: 10.1038/s41467-020-16266-w
• Publication Date: 2020-05-15T10:05:00Z
• Authors: Yuan Huang; Yu-Hao Pan; Rong Yang; Li-Hong Bao; Lei Meng; Hai-Lan Luo; Yong-Qing Cai; Guo-Dong Liu; Wen-Juan Zhao; Zhang Zhou; Liang-Mei Wu; Zhi-Li Zhu; Ming Huang; Li-Wei Liu; Lei Liu; Peng Cheng; Ke-Hui Wu; Shi-Bing Tian; Chang-Zhi Gu; You-Guo Shi; Yan-Feng Guo; Zhi Gang Cheng; Jiang-Ping Hu; Lin Zhao; Guan-Hua Yang; Eli Sutter; Peter Sutter; Ye-Liang Wang; Wei Ji; Xing-Jiang Zhou; Hong-Jun Gao
• Keywords: Condensed Matter - Materials Science; 670; Condensed Matter - Mesoscale and Nanoscale Physics; Engineering Science and Materials; Mechanical Engineering; Science; Q; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; 02 engineering and technology; 540; 530; 01 natural sciences; Article; Nanoscience and Nanotechnology; 0104 chemical sciences; Mechanics of Materials; Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Other Engineering Science and Materials; Other Mechanical Engineering; 0210 nano-technology

AbstractTwo-dimensional materials provide extraordinary opportunities for exploring phenomena arising in atomically thin crystals. Beginning with the first isolation of graphene, mechanical exfoliation has been a key to provide high-quality two-dimensional materials, but despite improvements it is still limited in yield, lateral size and contamination. Here we introduce a contamination-free, one-step and universal Au-assisted mechanical exfoliation method and demonstrate its effectiveness by isolating 40 types of single-crystalline monolayers, including elemental two-dimensional crystals, metal-dichalcogenides, magnets and superconductors. Most of them are of millimeter-size and high-quality, as shown by transfer-free measurements of electron microscopy, photo spectroscopies and electrical transport. Large suspended two-dimensional crystals and heterojunctions were also prepared with high-yield. Enhanced adhesion between the crystals and the substrates enables such efficient exfoliation, for which we identify a gold-assisted exfoliation method that underpins a universal route for producing large-area monolayers and thus supports studies of fundamental properties and potential application of two-dimensional materials.