(b) Graphene is an allotrope (form)of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice. It is a semimetal with small overlap between the valence and the conduction bands. Graphene has become a stellar nanomaterial due to the extremely high tensile strength, electrical conductivity, transparency and being the thinnest two-dimensional material in the world. Carbon-based nanomaterials have been applied in many fields.