Investigation of the Thermal Transport Properties Across Van der Waals Interfaces of 2D Materials

Two-dimensional (2D) materials have attracted extensive research interest in various applications in recent years due to their superior thermal, electrical, and optical properties, making them preferable for potential electronic and optoelectronic applications. These 2D materials form Van der Waals interfaces with common substrate materials due to fabrication and/or device requirements. Since the generated heat during the operation of the devices cause degradation and reliability concerns, interface thermal boundary conductance (TBCs) and in-plane thermal conductivities of the interfaces should be well understood for proper thermal management. Herein, we investigate the TBC and in-plane thermal conductivities of the Van der Waals interfaces of 2D materials by approach to-equilibrium molecular dynamics (AEMD) and non-equilibrium molecular dynamics (NEMD) simulations. Our results show that the TBC is higher for the interfaces with stronger phonon DOS and lattice match. Also, the increasing number of 2D material layers increases the TBC of the interface. The results also showed that the thermal conductivity of the materials forming the interface could affect each other's in-plane thermal conductivity. Changes in thermal conductivities of individual in-plane thermal conductivities can be as high as 70%. Change in thermal conductivity depends on the difference in thermal conductivities of materials in contact and only visible in the vicinity of the interface. Thermal management strategies should pay attention to the trade-off between the changes in individual thermal conductivities and TBC of the interfaces.