As an exotic material of the 21st century, graphene attracted a global attention in the fields of science, medicine and engineering. Graphene is the thinnest known material showing high electrical and thermal conductivity, mechanical flexibility, optical transparency, and low coefficient of thermal expansion behavior. There is different kind of approaches to produce graphene, including chemical and physical methods. Obviously the exceptional properties of graphene are extremely dependent on the exfoliation of the graphite to one-atom-thick planar sheet and defect less structure of graphene....