Interplay between localized and free exciton recombination in CdZnSe/ZnSe multi quantum well structures

Optical properties of CdxZn1-xSe/ZnSe (x = 0.12) multi quantum wells grown by molecular beam epitaxy on (100) GaAs substrate are presented and discussed. The photoluminescence, photoluminescence transients and optically detected cyclotron resonance experiments show that at low temperature excitons are either bound or are localized by potential fluctuations in the quantum wells. A strong contribution of a donor bound exciton emission to the low temperature PL spectra of quantum wells is shown. The chemical nature of the donor species is discussed.