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

An enhanced original computer program is applied to explain in detail the current-voltage characteristics of n-on-p long wavelength infrared HgCdTe photodiodes. The computer program solves the system of nonlinear continuity equations for carriers and Poisson equations. In the model ideal diode diffusion, generation-recombination, band-to-band tunneling, trap-assisted tunneling, and impact ionization are included as potential limiting mechanisms in the photodiodes. It is a clearly explained influence of Hg-vacancy doping and extrinsic doping of an active device region on dark current-voltage characteristics and an R0A product of HgCdTe photodiodes in a wide region of temperature and wavelengths. Special attention is directed to the dependence of tunneling probability on the shape of potential barrier with in an depletion region. The theoretical predictions are compared with experimental data of high quantity photodiodes published in the available literature.