Disorder induced transition of electrical properties of graphene by thermal annealing

We report the transport behavior of bilayer graphene grown by thermal chemical vapor deposition. The bilayer graphene films annealed at 700 degrees C in a furnace under Ar atmosphere exhibited transitions from a metal to a semiconductor or insulator, with temperature-dependent resistances. This modulation of electrical properties could be explained by two possible mechanisms: variable range hopping (VRH) and thermally activated (TA) conduction. In particular, Anderson localization was suggested for the metal-insulator (MI) transition in the transport of bilayer graphene, shifting the transition point to room temperature by an increase in the disorder up to 7.5x10(13) cm(-2).