Tunable interfacial thermal conductance by molecular dynamics

Abstract

Finally, we also replaced graphene layers by a few WSe_2 sheets and observed that interfacial thermal resistance of a Si/n-WSe_2/Si structure increases linearly with interface thickness at least for 1 < n <= 20, indicating diffusive heat transfer mechanism, in contrast to ballistic behavior of a few graphene layers. The corresponding thermal conductivity (0.048 W m^-1 K^-1) of a few WSe_2 layers is rather small. By comparing phonon dispersion of graphene layers and WSe_2 sheets, we attribute the diffusive behavior of a few WSe_2 sheets to abundant optical phonons at low and medium frequencies leading to very short mean free path.