Charge Transport in UV-Oxidized Graphene and Its Dependence on the Extent of Oxidation

Graphene oxides with different degrees of oxidation are prepared by controlling UV irradiation on graphene, and the charge transport and the evolution of the transport gap are investigated according to the extent of oxidation. With increasing oxygenous defect density [Formula: see text] , a transition from ballistic to diffusive conduction occurs at [Formula: see text] cm [Formula: see text] and the transport gap grows in proportion to [Formula: see text]. Considering the potential fluctuation related to the [Formula: see text] puddle, the bandgap of graphene oxide is deduced to be [Formula: see text] meV. The temperature dependence of conductivity showed metal–insulator transitions at [Formula: see text] cm [Formula: see text] , consistent with Ioffe–Regel criterion. For graphene oxides at [Formula: see text] cm [Formula: see text] , analysis indicated charge transport occurred via 2D variable range hopping conduction between localized [Formula: see text] domain. Our work elucidates the transport mechanism at different extents of oxidation and supports the possibility of adjusting the bandgap with oxygen content.