•  
  •  
 
Nano Research

Article Title

Raman scattering investigation of twisted WS2/MoS2 heterostructures: interlayer mechanical coupling versus charge transfer

Authors

Lishu Wu, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
Chunxiao Cong, School of Information Science and Technology, Fudan University, Shanghai 200433, ChinaFollow
Jingzhi Shang, Shaanxi Institute of Flexible Electronics, Northwestern Polytechnical University, Xi’an 710129, ChinaFollow
Weihuang Yang, Engineering Research Center of Smart Microsensors and Microsystems, Ministry of Education, College of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China
Yu Chen, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
Jiadong Zhou, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
Wei Ai, Shaanxi Institute of Flexible Electronics, Northwestern Polytechnical University, Xi’an 710129, China
Yanlong Wang, Key Laboratory of Chemical Lasers, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
Shun Feng, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
Hongbo Zhang, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
Zheng Liu, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
Ting Yu, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, SingaporeFollow

Keywords

van der Waals heterostructures, interlayer coupling, Raman scattering, twist angle, charge transfer

Abstract

Twisted van der Waals homo- and hetero-structures have aroused great attentions due to their unique physical properties, providing a new platform to explore the novel two-dimensional (2D) condensed matter physics. The robust dependence of phonon vibrations and electronic band structures on the twist angle has been intensively observed in transition metal dichalcogenide (TMD) homo-structures. However, the effects of twist angle on the lattice vibrational properties in the TMD heterostructures have not caused enough attention. Here, we report the distinct evolutions of Raman scattering and the underlying interlayer interactions in the twisted WS2/MoS2 heterostructures. The shifts and linewidths of E2g(Γ) and A1g(Γ) phonon modes are found to be twist angle dependent. In particular, analogous to that of the twisted TMD homostructures, the frequency separations between E2g(Γ) and A1g(Γ) modes of MoS2 and WS2 in the twisted heterostructures varying with twist angle correlate with the interlayer mechanical coupling, essentially originating from the spacing-related repulsion between sulfur atoms. Moreover, the opposite shift behaviors and broadening of A1g(Γ) modes caused by charge transfer are also observed in the twisted heterostructures. The calculated interlayer distances and band alignment of twisted WS2/MoS2 through density functional theory further evidence our interpretations on the roles of the interlayer mechanical coupling and charge transfer in variations of Raman features. Such understanding and controlling of interlayer interaction through the stacking orientation are significant for future optoelectronic device design based on the newly emerged 2D heterostructures.

Publisher

Tsinghua University Press

Share

COinS