▎ 摘　　要

We present a high-performance bilayer graphene (BLG) and mercury cadmium telluride (Hg1-xCdx=0.1867Te) heterojunction based very long wavelength infrared (VLWIR) conductive photodetector. The unique absorption properties of graphene enable a long carrier lifetime of charge carriers contributing to the carrier-multiplication due to impact ionization and, hence, large photocurrent and high quantum efficiency. The proposed p(+)-BLG/n-Hg0.8133Cd0.1867Te photodetector is characterized and analyzed in terms of different electrical and optical characteristic parameters using computer simulations. The obtained results are further validated by developing an analytical model based on drift-diffusion, tunneling and Chu's methods. The photodetector has demonstrated a superior performance including improved dark current density (approximate to 1.75 x 10(-14) mu A cm(-2)), photocurrent density (approximate to 8.33 mu A cm(-2)), internal quantum efficiency (QE(int) approximate to 99.49%), external quantum efficiency (QE(ext) approximate to 89%), internal photocurrent responsivity (approximate to 13.26 A W-1), external photocurrent responsivity (approximate to 9.1 A W-1), noise equivalent power (approximate to 8.3 x 10(-18) W), total noise current (approximate to 1.06 fA), signal to noise ratio (approximate to 156.18 dB), 3 dB cut-off frequency (approximate to 36.16 GHz), and response time of 9.4 ps at 77 K. Furthermore, the effects of different external biasing, light power intensity, and temperature are evaluated, suggesting a high QE(ext) of 3337.70% with a bias of -0.5 V near room temperature.