Exfoliation of 2D van der Waals crystals in ultrahigh vacuum for interface engineering

Zhenyu Sun; Xu Han; Zhihao Cai; Shaosheng Yue; Daiyu Geng; Dongke Rong; Lin Zhao; Yi-Qi Zhang; Peng Cheng; Lan Chen; Xingjiang Zhou; Yuan Huang; Kehui Wu; Baojie Feng

doi:10.1016/j.scib.2022.05.017

Exfoliation of 2D van der Waals crystals in ultrahigh vacuum for interface engineering

Sci Bull (Beijing). 2022 Jul 15;67(13):1345-1351. doi: 10.1016/j.scib.2022.05.017. Epub 2022 May 26.

Authors

Zhenyu Sun¹, Xu Han², Zhihao Cai¹, Shaosheng Yue¹, Daiyu Geng¹, Dongke Rong³, Lin Zhao¹, Yi-Qi Zhang¹, Peng Cheng¹, Lan Chen⁴, Xingjiang Zhou¹, Yuan Huang⁵, Kehui Wu⁶, Baojie Feng⁷

Affiliations

¹ Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
² Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China.
³ Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Science, China University of Geosciences, Beijing 100083, China.
⁴ Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Songshan Lake Materials Laboratory, Dongguan 523808, China.
⁵ Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China. Electronic address: yhuang@bit.edu.cn.
⁶ Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, China. Electronic address: khwu@iphy.ac.cn.
⁷ Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, China. Electronic address: bjfeng@iphy.ac.cn.

PMID: 36546267
DOI: 10.1016/j.scib.2022.05.017

Abstract

Two-dimensional (2D) materials and their heterostructures have been intensively studied in recent years due to their potential applications in electronic, optoelectronic, and spintronic devices. Nonetheless, the realization of 2D heterostructures with atomically flat and clean interfaces remains challenging, especially for air-sensitive materials, which hinders the in-depth investigation of interface-induced phenomena and the fabrication of high-quality devices. Here, we circumvented this challenge by exfoliating 2D materials in an ultrahigh vacuum. Remarkably, ultraflat and clean substrate surfaces can assist the exfoliation of 2D materials, regardless of the substrate and 2D material, thus providing a universal method for the preparation of heterostructures with ideal interfaces. In addition, we studied the properties of two prototypical systems that cannot be achieved previously, including the electronic structure of monolayer phospherene and optical responses of transition metal dichalcogenides on different metal substrates. Our work paves the way to engineer rich interface-induced phenomena, such as proximity effects and moiré superlattices.

Keywords: 2D van der Waals crystals; Interface engineering; Mechanical exfoliation; Ultrahigh vacuum; Universal method.