Thermal boundary conductance of buckled group IV,V, and III-V two-dimensional materials

An ongoing concern for 2D materials is their ability to thermally couple with an underlying substrate which acts as the primary pathway for heat removal in 2D devices. The thermal pathway from the 2D layer to substrate has been studied in graphene and various transition metal dichalcogenides. However, the literature still lacks a comprehensive analysis of thermal boundary conductance (TBC) for beyond-graphene materials. Here we use first-principles calculations and phonon interface transport modeling to calculate the TBC of beyond-graphene 2D materials, such as; silicene, germanene, BAs, and blue and black phosphorene, on amorphous and crystalline substrates. Our results show that the TBC of uncoated 2D-3D systems can be substantially bottlenecked by weak internal repopulation of ZA phonons, which are the primary carriers of heat across the interface. However, we then demonstrate that encapsulation not only improves TBC through increasing the repopulation of ZA phonons in the 2D layer, but also weakens the temperature dependence at temperatures above the Debye temperature of the 2D material. Lastly, we employ our model to explore the TBC of vdW heterostructures formed with various 2D materials. Our results help provide a roadmap for improved 2D-3D thermal interfaces.