ADF-STEM imaging of graphene suspended on TEM grid. (a) SEM image of graphene transferred to TEM grid, scale bar 5 μm. (b) Atomic scale ADF-STEM image showing the hexagonal lattice in the interior of a graphene grain. (c) ADF-STEM image showing intersection of two grains with a relative rotation of 27°. (d) Same image with pentagons, heptagons, and deformed hexagons formed along grain boundary highlighted (b, c, and d have scale bars of 5 Å) [28].