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

• Published in: Nature communications 2020-02, Vol.11 (1), p.1011-1011, Article 1011
• Main Authors: Luo, Ruichun, Xu, Wen Wu, Zhang, Yongzheng, Wang, Ziqian, Wang, Xiaodong, Gao, Yi, Liu, Pan, Chen, Mingwei
• Format: Article
• Language: English
• Subjects: 147/137; 639/301; 639/301/357/1018; Chalcogenides; Chemical vapor deposition; Electronic devices; Electronic equipment; Fabrication; Gold; Heavy metals; Heterojunctions; Humanities and Social Sciences; Interfaces; Metals; Molybdenum disulfide; Monolayers; multidisciplinary; Organic chemistry; Performance enhancement; Reconstruction; Science; Science (multidisciplinary); Substrates; Sulfur; Transition metal compounds; Tungsten disulfide
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-14753-8

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 Au 4 S 4 interfacial phase which is stabilized by the top MoS 2 and WS 2 monolayers. Moreover, the enhanced vdW interaction between the reconstructed Au 4 S 4 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. Material interfaces are highly crucial to improve device performances. Here, the authors report interfacial reconstruction at the Au {001} substrate surface and the top MoS 2 and WS 2 monolayers due to the formation of a metastable interfacial Au 4 S 4 phase. The reconstructed interface results in a p-type Schottky contact with reduced barrier height.