Photoluminescence of δ-doped GaAs/AlAs type-II superlattices

Experimental study of the photoluminescence of delta-doped GaAs/AlAs type-II superlattices has been carried out. The increase in impurity density from 2 (.) 10(10) to 7.5 (.) 10(11) cm(-2) in delta-layers is found to result in a 4- to 6-fold decrease of the integrated superlattice photoluminescence (PL) intensity and a more significant decrease of excitonic PL intensity by 70-80 times, accompanied by an increase in the exciton radiative recombination rate. Investigations of the PL kinetics show that the impurity-induced quenching of excitonic PL is not caused by the growth of the density of non-radiative recombination centers. We conclude that the built-in electric fields induced by ionized impurity planes inhibit the exciton formation and are the principle reason for the decrease in the excitonic PL intensity with the doping increase. The results of a study of the peculiarities of donor-acceptor recombination in such superlattices are presented.