Strain regulated interlayer coupling in WSe₂/WS₂heterobilayer

Strain engineering can effectively modify the materials lattice parameters at atomic scale, hence it has become an efficient method for tuning the physical properties of two-dimensional (2D) materials. The study of the strain regulated interlayer coupling is deserved for different kinds of heterostructures. Here, we systematically studied the strain engineering of WSe₂/WS₂heterostructures as well as their constituent monolayers. The measured Raman and photoluminescence spectra demonstrate that the strain can evidently modulate the phonon energy and exciton emission of monolayer WSe₂and WS₂as well as the WSe₂/WS₂heterostructures. The tensile strain can tune the electronic band structure of WSe₂/WS₂heterostructure, as well as enhance the interlayer coupling. It is further revealed that the photoluminescence intensity ratio of WS₂to WSe₂in our WSe₂/WS₂heterobilayer increases monotonically with tensile strain. These findings can broaden the understanding and practical application of strain engineering in 2D materials with nanometer-scale resolution.