Chemical and electrical modifications of few-layer graphene films via sub-10 keV electron beam irradiation

Graphene has attracted special attention due to its mechanical and electrical properties. In this work, we describe the effects of sub-10 keV electron beam irradiation on the electrical conductivity of few-layer graphene films deposited on a glass substrate. The irradiation process was performed in vacuum at 10^–6 Torr for 30 min per sample. The superficial chemical structure and optical properties of the samples were evaluated before and after electron irradiation using spectroscopic techniques (UV-Vis, Raman, and XPS), and the Van der Pauw method was used to determine the sheet resistance. It was found that the sheet resistance and the defect density decrease as the energy of incident electrons increases. For instance, the sheet resistance has been reduced by 17.3% after the sample was irradiated with a 10 keV electron beam. This could be explained by the reduction of defect density on the irradiated samples caused by the removal of oxygen content on graphene flakes, estimated by Raman and XPS, respectively. Hence, electron beam irradiation could be used to modify the electrical conductivity of graphene films based on defect engineering.