Interfacial thermal conductance of multilayer graphene/MoS2 heterostructure

Abstract

We investigated the Interfacial thermal conductance (ITC) with a heterogeneous structure of a bilayer of MoS2 embedded in the middle of four graphene layers by non-equilibrium molecular dynamics (NEMD). Surprisingly, the ITC of MoS2/MoS2 (M/M) is significantly higher than that of the graphene/MoS2 (G/M). Interestingly, changes in the cross-sectional dimensions do not affect the ITC of the G/M and M/M, as the constant interface spacing preserves their structural characteristics so that phonon mean free range remains unchanged. Intriguingly, the interfacial strain affects the ITC notably. A 10% compression strain increases the G/M ITC by 100%, while a 10% tension strain reduces it by 70%. Unexpectedly, increasing defect concentration near the G/M interface leads to a decrease in thermal conductance. We find that graphene plays a dominant role in heat conduction within the heterostructure, while defects primarily enhanced low-frequency phonon vibrations of graphene, with MoS2 vibrations remaining largely unaffected. Due to the increase in defect rate, the out-of-plane phonon coupling is weakened, thus leading to a decrease in G/M ITC. These findings provide concise insights into the heat conduction of G/M heterostructures.