Enhanced numerical analysis of current-voltage characteristics of long wavelength infrared p-on-n HgCdTe photodiodes

An enhanced original computer programme is applied to explain in detail the current-voltage characteristics of p-on-n long wavelength infrared (LWIR) HgCdTe photodiodes. The computer programme solves the system of non-linear continuity equations for carriers and Poisson equations. In the model ideal diode diffusion, generation-recombination, band-to-band tunnelling, trap-assisted tunnelling, and impact ionization are included as potential limiting mechanisms in the photodiodes. It is a clearly explained influence of extrinsic doping of an active device region on dark current-voltage characteristics and on R(o)A product of HgCdTe photodiodes in a wide region of temperature and wavelengths. Special attention is directed to the dependence of tunnelling probability on the shape of potential barrier within the depletion region. The theoretical predictions are compared with experimental data of high quantity photodiodes published in the available literature.