Tuning thermal resistance of SiC crystal/amorphous layered nanostructures via changing layer thickness

Abstract

Interfacial thermal resistance plays a key role in reducing the overall thermal conductivity of SiC nanostructure, by which it is of promising to manage thermal properties in nano-devices. Using non-equilibrium molecular dynamics simulations, we study effective thermal conductivities of three SiC crystal/amorphous layered nanostructures and calculate interfacial thermal resistance of SiC nanostructures with different layer thicknesses. It is found that phonon scatterings at interfaces are dependent on the inserted layer thickness in sandwich models and determine the interfacial thermal resistance. Based on the layer thickness dependence of phonon scattering at interface, it is verified that the thermal conductivity of hybrid SiC superlattices could be engineered. Particularly, as the layer thickness of SiC superlattices scales down to a few nanometers, ultra-low thermal conductivity even below that of the amorphous limit can be achieved by tuning the thickness ratio of amorphous to crystal layers. Our findings could provide insights into the nano-engineering of hybrid SL with tunable thermal conductivity.