Enhanced absorption of long-wave infrared light from silicon microholes array by filling in its gaps with graphene film

As an exciting material for its excellent electrical and optical properties, graphene is widely used in optoelectronics currently. In this work, the absorption of long-wave infrared light from silicon microholes (Si-MHs) array, in the gaps of which both graphene and metal films are filled in to form as the active layers, is simulated with finite-difference time-domain (FDTD) method by considering the anisotropic properties of graphene. Our simulations show the position and the intensity of the absorption peaks can be linearly modulated by the quadrate Si-MHs' diameter within a certain range. The absorption of the Si-MHs array with a hybrid graphene (350 nm)/Au (50 nm)/graphene (350 nm) film can reach close to 100 %. Also, the absorption properties of the hybrid graphene/metal/graphene film integrated into Si-MH array demonstrate negligible variation with any metal such as Au, Ag, Al and Cu. Further, our simulation is confirmed by the reports published previously. Thus, it provides a novel method for long-wave infrared optoelectronics.