Accurate Local Modulation of Graphene Terahertz Metamaterials by Direct Electron Beam Irradiation

Electrical gating has been typically used for Graphene-based devices to deliver high performance with superior electrical controllability. In this study, we utilize direct electron beam irradiation to attain the electrical controllability of graphene. The newly established system combines terahertz time-domain spectroscopy (TDS) with scanning electron microscopy (SEM). We experimentally demonstrate the precise localized tuning of graphene terahertz metamaterials, as the size and position of the electron beam generated by SEM are highly controllable. Furthermore, graphene metamaterials with different chemical potentials are simulated, and the results are highly consistent with the experiments.