A Highly Efficient Bilayer Graphene-HgCdTe Heterojunction Based $p^{+}-n$ Photodetector for Long Wavelength Infrared (LWIR)

In this paper, p⁺ -bilayer graphene (BLG)/n@ Hg_0.7783Cdo_0.2217Te heterojunction based long wavelength infrared (LWIR: 2-12 μm) photodetector is reported. The LWIR radiations are absorbed in lightly doped n- Hg_0.7783Cd_0.2217Te active layer. The drift-diffusion approach is used for the simulation of the device. Different recombination mechanism models such as Shockley-Read-Hall, Auger, and optical are considered for computing dark current. The photodetector exhibits dark current of 3.5 pA, photocurrent of 1.9 nA, and I_ph/I_dark ratio of 543 at -1 V bias. The maximum external quantum efficiency (QE_ext) of 88.38%, photocurrent responsivity of 4.5 AW^-1, specific detectivity (D*) of 1.8 × 10¹⁵ cmHz^1/2W^-1, noise equivalent power (NEP) of 3.53 × 10^-19 W, and the 3-dB bandwidth of about 64.8 GHz at -0.5 V is achieved at 77 K, confirms the suitability of proposed photodetector for low noise applications.