Figure 2. Fracture behaviors of the CVD-graphene under static load condition.

(a), Schematic illustration of the bulge test of the freely suspended CVD-graphene on Si substrate with a cylindrical hole. (b), One exemplified image for precisely measuring the crack extension length of the mother crack (a1) and the branched crack (a2). (c), Crack extension histories of the mother/branched crack with typical images showing fracture evolution. (d), Propagation speed diagram of the mother crack and crack arresting behaviors arising out of thickness differences (See the text). The growth rate of the branched crack can be found in Fig. S8.