“…The first successful isolation of a high-quality single-layer graphene using the mechanical exfoliation method from bulk graphite by Geim and Novoselov in 2004 opened a new era for low-dimensional materials science, 1–6 in which the successful fabrication of monolayer graphene was realized after a very long process since the first theory of graphene was proposed by P. R. Wallace in 1947, 7 and the first experimental discovery of graphene was conducted by H. P. Boehm et al in 1962. 8,9 Since its successful fabrication in 2004, single-layer graphene or two-dimensional (2D) graphene has drawn much attention because its one-atom thickness, 2D quantum confinement, and highly symmetric hexagonal lattice can result in many novel properties, 10 especially the anomalous quantum Hall effect, 11 and ultrahigh charge-carrier mobility.…”