Analysis injection area-dark current characteristics for mid-wavelength HgCdTe photodiodes

In this paper, we study the relationship between dark current mechanism and the injection area of mid-wavelength infrared (MWIR) HgCdTe photovoltaic detectors. A simultaneous-mode nonlinear fitting program for n-on-p mid-wavelength HgCdTe infrared detectors is reported. It is found that the impact of diffusion mechanism gradually weakens and the effect of generation-recombination mechanism becomes more significant as the area of injection increasing under forward bias. The effect of trap-assisted tunneling mechanism gradually weakens as the area of injection increasing under middle reverse bias and band-to-band tunneling mechanism has less impact on dark current of MWIR HgCdTe photodiodes. And as the area of injection increasing, the effect of surface leak mechanism is gradually decrease. Finally, we find the reversed welding pressure and the arrangement of common electrode for MWIR HgCdTe Photodiodes also impacts diffusion mechanism and generation-recombination mechanism under forward bias.