PHOTOLUMINESCENCE TRANSIENTS DUE TO DONOR AND EXCITON AVALANCHE BREAKDOWN

Time dependence of excitonic, free electron-acceptor and donor-accepto r-pair photoluminescence (PL) was investigated at low temperatures, wh en impact ionization of shallow donors and excitons predominates. The PL transients were excited by periodically applying short electrical p ulses to epitaxial n-GaAs samples illuminated by a continuous laser ir radiation. The experimental results are analyzed by using the time-dep endent rate equation system, with the donor and exciton impact ionizat ion and thermal recombination processes taken into account. A critical analysis of corresponding rate coefficients and collection of coeffic ients for simulation of the avalanche breakdown transients ark present ed. (C) 1998 Elsevier Science B.V. All rights reserved.