Tuning thermal transport across monolayer MoS2/Si heterostructure via substrate nanogrooving

Abstract

Substrate-supported two-dimensional (2D) material heterostructures have been widely applied in electronic and photonic devices. However, the substrate reduces the original high thermal conductivity of 2D materials and limits the heat dissipation due to the interface thermal resistance. Here, the effects of the substrate surface topography on the thermal transport properties of the MoS2-Si heterostructure are investigated via molecular dynamics simulations. The decreased in-plane thermal conductivity of the monolayer MoS2 and surprisingly enhanced interface thermal transport of the MoS2-Si heterostructure are found by introducing the shallow nanogroove on the substrate surface. The results are ascribed to the morphology change of the supported MoS2, which bends to fit the substrate surface topography due to the van der Waals force at the small groove depth. In addition, the force weakens and the supported MoS2 restores to flat with the increase of groove depth, resulting in higher in-plane thermal conductivity and thermal resistance compared to those without grooves, which is due to the disappearance of the substrate effect in the nanogroove area. This work elucidates the fundamental understanding of heat transfer in heterostructures. It provides new insights to enhance the heat dissipation in electronic devices by introducing nanoscale roughness.