Crack Propagation and Fracture Toughness of Graphene Probed by Raman Spectroscopy

Fracture behaves as one of the most fundamental issues for solid materials. As a one-atom-thick crystal, many aspects in fracture mechanics of graphene are of high significance, such as the crack propagation and its fracture toughness. Here we present a method to study the fracture characteristics of graphene using Raman spectroscopy and designed chemical-vapor-deposited monolayer graphene with preset cracks. The dynamic fracture process of graphene was experimentally observed, and its fracture toughness was obtained using Griffith's criterion based on the strain distribution derived from the frequency shifts of Raman bands. The fracture toughness of K-c = 6.1 +/- 0.6 MPa root m and G(c) = 37.4 +/- 6.7 J/m(2) are comparable with the previously reported theoretical and experimental values, and we believe that this simple and easy-to-operate approach of characterizing the fracture of graphene using Raman spectroscopy can also be extended to other two-dimensional materials.