Room temperature performance analysis of bilayer graphene terahertz photodetector

In this paper, the room temperature performance of bilayer graphene terahertz photodetector is studied by calculating of its dark current and dark current limited detectivity at room temperature. In the first step the spectral dependences of the photodetector responsivity as function of the device structural parameters is calculated. It is demonstrated that at the radiation frequency close to the resonant frequencies of plasma oscillations, the responsivity can exhibit sharp and very high maxima corresponding to fairly large responsivity values. In the second step the dark current and dark current limited detectivity for different temperatures, bias voltage, and widths of graphene layer is calculated and analyzed. The obtained results show that for the bilayer graphene photodetector with W = 5 nm, L = 20 μm, Vb = 2 V, Vg = 2 V, value of dark current limited detectivity D*, at room temperature T = 300 °K and also T = 200 °K are 9×106   cmHz/W and ∼6×109   cmHz/W, respectively.