In-plane and cross-plane thermal conductivities of molybdenum disulfide

Abstract

We investigate the in-plane and cross-plane thermal conductivities of molybdenum disulfide (MoS2) using non-equilibrium molecular dynamics simulations. We find that the in-plane thermal conductivity of monolayer MoS2 is about 19.76 W mK−1. Interestingly, the in-plane thermal conductivity of multilayer MoS2 is insensitive to the number of layers, which is in strong contrast to the in-plane thermal conductivity of graphene where the interlayer interaction strongly affects the in-plane thermal conductivity. This layer number insensitivity is attributable to the finite energy gap in the phonon spectrum of MoS2, which makes the phonon–phonon scattering channel almost unchanged with increasing layer number. For the cross-plane thermal transport, we find that the cross-plane thermal conductivity of multilayer MoS2 can be effectively tuned by applying cross-plane strain. More specifically, a 10% cross-plane compressive strain can enhance the thermal conductivity by a factor of 10, while a 5% cross-plane tensile strain can reduce the thermal conductivity by 90%. Our findings are important for thermal management in MoS2 based nanodevices and for thermoelectric applications of MoS2.