Luo Ruichun, Xu Wen Wu, Zhang Yongzheng, Wang Ziqian, Wang Xiaodong, Gao Yi, Liu Pan, Chen Mingwei
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.
Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA.
Nat Commun. 2020 Feb 21;11(1):1011. 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 AuS interfacial phase which is stabilized by the top MoS and WS monolayers. Moreover, the enhanced vdW interaction between the reconstructed AuS 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.
半导体二维过渡金属二硫属化物（2D TMDs）与导电金属（如金）之间的范德华（vdW）异质结的结构和性质，对基于2D-TMD的电子器件性能有显著影响。化学气相沉积是大规模合成和制造具有天然形成的TMD/金属vdW界面的2D TMD电子产品最有前景的方法之一。然而，vdW界面的结构和化学性质尚不太清楚。在此，我们报道了TMD单层与金衬底之间的界面重构。硫的参与导致Au{001}表面重构，形成亚稳的AuS界面相，该相由顶部的MoS和WS单层稳定。此外，重构的AuS界面相与TMD单层之间增强的vdW相互作用导致从n型TMD-金肖特基接触转变为p型接触，且能垒高度降低。
