The mechanical and thermal properties of MoS2–WSe2 lateral heterostructures

Abstract

The recently fabricated monolayer MoS₂–WSe₂ lateral heterostructures are promising for many interesting applications, such as p–n diodes, photodetectors, transistors, sensors, light-emitting diodes and thermoelectric and flexible nanodevices. In this work, we study the mechanical and thermal properties of MoS₂–WSe₂ lateral heterostructures by using molecular dynamics (MD) simulations based on the recently parameterized Stillinger-Weber (SW) potential. It is found that the fracture strength and fracture strain of MoS₂–WSe₂ lateral heterostructures are dictated by the mechanical properties of MoS₂, and are very sensitive to temperature. However, when a crack is introduced in the MoS₂–WSe₂ heterostructures, failure may occur either in MoS₂ or WSe₂, depending on the crack length and location. Interestingly, the fracture strengths obtained from our MD simulations are in agreement with those obtained from the Griffith theory. Our MD simulations further reveal that, in addition to the low thermal conductivities of MoS₂ and WSe₂, the MoS₂–WSe₂ heterojunctions exhibit a very low interfacial thermal conductance, which is about one order of magnitude lower than that of graphene–hBN heterojunctions.