EXTRINSIC PHOTOLUMINESCENCE IN COUPLED-WELL GAAS/ALGAAS SUPERLATTICES

Extrinsic luminescence involving residual donor and acceptor impurities in a nominally undoped, coupled-well 80 Angstroms GaAs/20 Angstroms Al//0//. //3Ga//0//. //7As superlattice grown by organometallic chemical vapor deposition has been investigated. Separate peaks are observed in the luminescence lineshape corresponding to acceptors in the barriers and in the wells, with ionization energies of about 13. 5 and 31. 9 meV, respectively. The relative amplitudes of the peaks indicate that most of the acceptors are located in the AlGaAs barriers. Varying the temperature from 1. 7 to 31 K and the excitation intensity from 0. 28 to 1400 mW cm** minus **2 reveals both donor-to-acceptor and miniband-to-acceptor recombination involving each type of acceptor.