Current-voltage characteristic of a narrow-band semiconductor taking into account ionization of impurities

The current-voltage characteristic of a material with a narrow conduction band in a strong electric field is studied taking into account ionization of deeply lying impurities in the model, in which collisions of charge carriers are described in the Fokker–Planck approximation. The results are compared with analogous results obtained in the $\nu$ approximation. It is shown that the results obtained earlier in the $\nu$ approximation coincide with our results to within $\sim$5%. It is noted that the Fokker-Planck model additionally provides the temperature dependence of the current-voltage characteristic.