Nanostructuring of CVD graphene by high-energy heavy ions

In this study, CVD graphene with a typical set of structural features (domains, folds and blisters) is used to see the relation between the effects of its nanostructuring by high-energy ion irradiation (Xe and Kr with energies 26-167 MeV) and the graphene structure. The pore size was found to depend on the domain size and the ion energy, and equal to 10-30 nm and 60-80 nm for domains of 1-3 mu m and-10 mu m, respectively. The pore density was estimated as-10% from the ion fluence. The maximum pore density, approximately equal to the ion dose, was found in the strained graphene blisters. The formation of more complex structural defects (presumably, ultrashort nanotubes covered with a graphene monolayer on the top) is also revealed after the ion irradiation in few-layer graphene. The top layer preservation after irradiation was justified by the molecular dynamics simulation and caused by lower energy losses (absence of the electrons knocked out of the previous layers). The possibility of forming vertical wells in ultrashort nanotubes, due to interlayer covalent bonds at the edges of some pores, is very attractive for applications. The use of CVD graphene provides ample opportunities for controlling the structure and properties of nanostructured materials.