Magneto-optical properties of Zn0.95Mn0.05Se/Zn0.76Be0.08Mg0.16Se quantum wells and Zn0.91Mn0.09Se/Zn0.972Be0.028Se spin superlattices

We have performed magnetoluminescence and magnetoreflectance studies on novel semimagnetic semiconductor heterostructures based on (ZnMn)Se/(ZnBeMg)Se. The successful fabrication and various optical properties of that system are demonstrated by Zn0.95Mn0.05Se/" " Zn0.76Be0.08Mg0.16Se single quantum wells. The exciton spin splitting was used to determine the valence-band offset for (ZnMn) Se/(ZnBeMg)Se to 0.22 of the total band-gap discontinuity. Weakly; confining multiple quantum wells made of Zn0.91Mn0.09Se/Zn0.972Be0.028Se demonstrate a change of the band alignment from type I to type II for one of the exciton spin components in external magnetic fields which results in the formation of a spin superlattice. This spin superlattice formation manifests itself in an asymmetric Zeeman splitting of a spatially direct exciton caused by a spin-dependent change of the exciton binding energy. A pronounced broadening of the exciton in reflectance and photoluminescence excitation spectra was observed when scattering into the (ZnBe)Se barriers becomes possible. [S0163-1829(99)01028-0].