Strain effects on the electronic and optical properties of Van der Waals heterostructure MoS2/WS2: A first-principles study

In the present work, the effect of biaxial and uniaxial strains on the electronic and optical properties of heterostructure MoS2/WS2 has been studied by density functional theory. Our numerical calculations demonstrate that the heterostructure MoS2/WS2 is an indirect semiconductor with a type-II band alignment and its energy gap is 1.45 eV. Besides, the semiconductor–metal transition can be found at large biaxial strain of 14% in the van der Waals heterostructure MoS2/WS2. Influence of the strain engineering on the optical spectra of the heterostructure MoS2/WS2 are also considered in this work. Our calculations indicate that, while the effect of uniaxial strain on the optical properties is quite weak, the optical parameters of the heterostructure MoS2/WS2 depend strongly on the biaxial strain. Our predicted results may be a reference for future experimental and theoretical studies of the heterostructures. © 2019 Elsevier B.V.