Mechanical properties of homogeneous and heterogeneous layered 2D materials

Transition metal dichalcogenides (TMDC) such as molybdenum disulfide (MoS₂) are 2D materials that are promising for flexible electronics and piezoelectric applications, but their low mechanical strength limits practical use. In this work, we study the mechanical properties of heterostructures containing MoS₂ and graphene, another 2D material with exceptional mechanical properties, using atomistic molecular dynamics simulations of nanoindentation. We consider bi- and tri-layer heterostructures where graphene either supports or encapsulates MoS₂, and we compare to the monolayers and homogeneous bilayers. We extract mechanical properties (Young´s modulus) from nanoindentation simulations. All of the heterostructures have larger Young´s moduli than the mono- and bi-layer MoS₂, demonstrating that graphene provides mechanical reinforcement regardless of layer stacking order. Our results demonstrate the potential of heterostructures to improve the mechanical properties of TMDC materials, which would increase their utility for device applications.