Graphene/ZnO van der Waals Stacks for Thermal Management

The weak van der Waals (vdW) interactions and the unique interface that dominates layered 2D materials provide a powerful platform for materials engineering. The proximity effects in vdW heterostructures can be tailored to design novel and improved materials. Herein, we report a systematic study of the mechanical behavior, thermal properties, and lattice dynamics of the ZnO-proximitized graphene (ZnO/G) vdW material using first-principles methods. Our results show superior mechanical properties of ZnO/G that can withstand creeping up to a reasonable tensile and compressive strain. We demonstrate a high tunability of the vibrational properties, both with strain and temperature. The thermal properties change significantly with temperature leading to a negative thermal expansion coefficient with an absolute maximum value of ∼−4.31 × 10^–6 K^–1 at 105 K. The combination of superior tunable mechanical and thermal properties makes the ZnO/G vdW system a promising material for applications in mechanically actuated thermal management nanodevices.