Thermal conductivity of MoS2/MoSe2 heterostructures: The role of lattice mismatch, interlayer rotation and species intermixing

•Synthesis processes heavily affect the thermal conductivity of heterostructures.•Lattice mismatch enhances the thermal conductivity due to the strain effects.•Thermal conductivity of bilayers is not sensitive to the interlayer rotation. Van der Waals heterostructures formed by stacking different two-dimensional transition metal dichalcogenide sheets exhibit unusual properties compared with single-layer counterparts and are finding promising applications in optics and electronics. Different synthesis processes may lead to various defects, such as lattice mismatch, interlayer rotation and species intermixing. We adopt non-equilibrium molecular dynamics simulations to explore the influence of these factors on the thermal conductivity of bilayer heterostructures that are formed by single-layer MoS2 and MoSe2 sheets. The thermal conductivity of the bilayer made up of unstrained MoS2 and MoSe2 layers is 121% larger than the AB stacked one. Detailed phonon scattering analysis reveals that the tensile strain-induced enhancement of anharmonicity is the main reason. The study of the twisted bilayer structure shows that the interlayer rotation considerably alters the phonon band structure but has little impact on the thermal conductivity. We also find that thermal conductivity varies inversely with the species intermixing ratio due to the increase of localized phonon modes. Our findings in this work could provide some guidelines for the synthesis process of van der Waals heterostructures with exceptional thermal properties.