“…The unusual properties of graphene have attracted many theoretical studies directed toward gaining an understanding of the fundamental size and dimensionality dependence of the special properties of layered materials. [19,27,65] Another popular research direction has been the detailed study of the effect of the substrate on each of the properties that had been studied previously, leading to studies on freely suspended graphene. [66] Variations on many properties of graphene have been probed by systematic studies of their dependence on the Fermi level, since the Fermi level controls the carrier concentration and the balance of electrons and holes.…”