Kinetics of low-temperature charge-carrier recombination in disordered hopping systems

Energetic relaxation and recombination of charge carriers are considered at low temperatures in disordered hopping systems, taking the increasing occupation of deep localized states into account. It is shown that, in the course of carrier relaxation controlled by monomolecular recombination, the occupational density of localized states does not change with time. If bimolecular recombination represents the dominant mode of the carrier-density relaxation, all deep localized states will sooner or later be occupied and the filling effect plays an important role in the process of relaxation.