▎ 摘　　要

In this paper, we present a switchable and tunable common-frequency broadband terahertz (THz) absorp-tion/reflection/transmission functional device based on graphene and photosensitive silicon. When photosen-sitive silicon is in the metallic state and graphene Fermi energy level is at EF = 1 eV, the absorptance (A) is greater than 90% in the range of 1.42 to 3.34 THz, and adjusting graphene Fermi energy level to EF = 0 eV, the reflectance (R) is greater than 80% from 0.5 to 4.5 THz. While photosensitive silicon switches to the dielectric state and graphene Fermi energy level at EF = 0 eV, the transmittance (T) is greater than 80% in the range of 1.42 to 3.34 THz. Simulated data were verified by the coupled-mode theory (CMT). We believe that the proposed structure can be applied to wireless communication, sensing and imaging.