Van der Waals interfacial reconstruction in monolayer transition-metal dichalcogenides and gold heterojunctions

Ruichun Luo; Wen Wu Xu; Yongzheng Zhang; Ziqian Wang; Xiaodong Wang; Yi Gao; Pan Liu; Mingwei Chen

doi:10.1038/s41467-020-14753-8

Van der Waals interfacial reconstruction in monolayer transition-metal dichalcogenides and gold heterojunctions

Nat Commun. 2020 Feb 21;11(1):1011. doi: 10.1038/s41467-020-14753-8.

Authors

Ruichun Luo^#^{1

2}, Wen Wu Xu^#³, Yongzheng Zhang⁴, Ziqian Wang^{2

4}, Xiaodong Wang¹, Yi Gao⁵, Pan Liu^{6

7}, Mingwei Chen^{8

9}

Affiliations

¹ Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
² Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA.
³ Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, 315211, P. R. China.
⁴ WPI Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.
⁵ Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, P. R. China.
⁶ Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China. panliu@sjtu.edu.cn.
⁷ WPI Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan. panliu@sjtu.edu.cn.
⁸ Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA. mwchen@jhu.edu.
⁹ WPI Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan. mwchen@jhu.edu.

^# Contributed equally.

Abstract

The structures and properties of van der Waals (vdW) heterojunctions between semiconducting two-dimensional transition-metal dichalcogenides (2D TMDs) and conductive metals, such as gold, significantly influence the performances of 2D-TMD based electronic devices. Chemical vapor deposition is one of the most promising approaches for large-scale synthesis and fabrication of 2D TMD electronics with naturally formed TMD/metal vdW interfaces. However, the structure and chemistry of the vdW interfaces are less known. Here we report the interfacial reconstruction between TMD monolayers and gold substrates. The participation of sulfur leads to the reconstruction of Au {001} surface with the formation of a metastable Au₄S₄ interfacial phase which is stabilized by the top MoS₂ and WS₂ monolayers. Moreover, the enhanced vdW interaction between the reconstructed Au₄S₄ interfacial phase and TMD monolayers results in the transition from n-type TMD-Au Schottky contact to p-type one with reduced energy barrier height.