Periodic Modulation of the Doping Level in Striped MoS2 Superstructures

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• 作者：Xiebo Zhou ; Jianping Shi ; Yue Qi ; Mengxi Liu ; Donglin Ma ; Yu Zhang ; Qingqing Ji ; Zhepeng Zhang ; Cong Li ; Zhongfan Liu ; Yanfeng Zhang
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：March 22, 2016
• 年：2016
• 卷：10
• 期：3
• 页码：3461-3468
• 全文大小：531K
• ISSN：1936-086X

文摘

Although the recently discovered monolayer transition metal dichalcogenides exhibit novel electronic and optical properties, fundamental physical issues such as the quasiparticle bandgap tunability and the substrate effects remain undefined. Herein, we present the report of a quasi-one-dimensional periodically striped superstructure for monolayer MoS₂ on Au(100). The formation of the unique striped superstructure is found to be mainly modulated by the symmetry difference between MoS₂ and Au(100) and their lattice mismatch. More intriguingly, we find that the monolayer MoS₂ is heavily n-doped on the Au(100) facet with a bandgap of 1.3 eV, and the Fermi level is upshifted by ∼0.10 eV on the ridge (∼0.2 eV below the conduction band) in contrast to the valley regions (∼0.3 eV below the conduction band) of the striped patterns after high-temperature sample annealing process. This tunable doping effect is considered to be caused by the different defect densities over the ridge/valley regions of the superstructure. Additionally, an obvious bandgap reduction is observed in the vicinity of the domain boundary for monolayer MoS₂ on Au(100). This work should therefore inspire intensive explorations of adlayer–substrate interactions, the defects, and their effects on band-structure engineering of monolayer MoS₂.