Theoretical Study of the Electron Transport in Graphene with Vacancy and Residual Oxygen Defects after High-Temperature Reduction

It is known that a high-temperature reduced-graphene-oxide (HT-RGO) exhibits 3 orders of magnitude increase in the conductivity compared to original graphene oxide but still 3 orders of magnitude below the value of pristine graphene. Substantial amounts of defects that remain in the reduced sample are responsible for the inferior transport quality. On the basis of the defect model which involves C vacancies and the O substitution of edge C atoms, we study the electronic structure and conductivity of HT-RGO using nonequilibrium Green's function theory in tight binding and density functional theory schemes. It is shown that electrons are localized within 10–40 nm due to vacancy defects. We also discuss the transport behavior via such localized carriers in connection with recent experimental findings.