Preliminary experimental study of graphene-based terahertz radiation excited by an electron beam

There are several proposed graphene-based coherent terahertz radiation sources excited by an electron beam in the terahertz frequency band. The properties of graphene such as graphene conductivity are of great importance to achieve these graphene-based terahertz radiation sources. In this paper, based on terahertz time-domain spectroscopy, the effects of a 400- eV electron beam on graphene conductivity are presented. The results indicate that exposure to a 400-eV electron beam can cause n-doping in the graphene from the interaction of the electron beam with the graphene film. After a long-time electron beam irradiation, the graphene conductivity decreases, indicating that defects and damages are created in the graphene. The findings are valuable for the further experimental study to realize graphene-based terahertz radiation sources excited by an electron beam.