Two components of donor-acceptor recombination in compensated semiconductors. Analytical model of spectra in presence of electrostatic fluctuations

We report numerical and analytical studies of the donor-acceptor recombination in compensated semiconductors. Our calculations take into account random electric fields of charged impurities which are important in non zero compensation case. We show that the donor-acceptor optical spectrum can be described as a sum of two components: monomolecular and bimolecular. In the low compensation limit we develop two analytical models for both types of the recombination. Also our numerical simulation predicts that these two components of the photoluminescence spectra can be resolved under certain experimental conditions.