Generation-recombination and diffusion currents in HgMnTe n(+)-p junctions

Special features of the distributions of the space charge, the electric-fie ld strength, and potential in the p-n junction in the narrow-gap HgMnTe sem iconductor were considered using the Poisson equation. It is shown that, as the band gap narrows, the effect of free charge carriers induces the coord inate dependence of electric-field strength to deviate from the linear depe ndence and that of the potential to deviate from the quadratic dependence. As a result of this, and also because of an appreciable increase in the dif fusion potential in the n(+)-p junction with the degenerate n(+) region, th e mechanisms of the charge transport become peculiar: the voltage dependenc e of the recombination current deviates from those following from the conve ntionally used analytical expressions, whereas for higher bias voltages, th e diffusion current of holes from the lightly doped p region into the n(+) region is prevalent. (C) 2001 MAIK "Nauka/ Interperiodica".