Strain regulated interlayer coupling in WSe 2 /WS 2 heterobilayer

Abstract 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 WSe 2 /WS 2 heterostructures 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 WSe 2 and WS 2 as well as the WSe 2 /WS 2 heterostructures. The tensile strain can tune the electronic band structure of WSe 2 /WS 2 heterostructure, as well as enhance the interlayer coupling. It is further revealed that the photoluminescence intensity ratio of WS 2 to WSe 2 in our WSe 2 /WS 2 heterobilayer increases monotonically with tensile strain. These findings can broaden the understanding and practical application of strain engineering in 2D materials with nanometer-scale resolution.