Magneto-optical properties of ${\mathrm{Zn}}_{0.95}{\mathrm{Mn}}_{0.05}{\mathrm{S}\mathrm{e}/\mathrm{Z}\mathrm{n}}_{0.76}{\mathrm{Be}}_{0.08}{\mathrm{Mg}}_{0.16}\mathrm{Se}$ quantum wells and ${\mathrm{Zn}}_{0.91}{\mathrm{Mn}}_{0.09}\mathrm{S}\mathrm{e}/{\mathrm{Zn}}_{0.972}{\mathrm{Be}}_{0.028}\mathrm{Se}$ spin superlattices

We have performed magnetoluminescence and magnetoreflectance studies on novel semimagnetic semiconductor heterostructures based on $\left(\mathrm{ZnMn}\right)\mathrm{Se}$/$\left(\mathrm{ZnBeMg}\right)\mathrm{Se}$. The successful fabrication and various optical properties of that system are demonstrated by ${\mathrm{Zn}}_{0.95}{\mathrm{Mn}}_{0.05}\mathrm{Se}$/” ”${\mathrm{Zn}}_{0.76}{\mathrm{Be}}_{0.08}{\mathrm{Mg}}_{0.16}\mathrm{Se}$ single quantum wells. The exciton spin splitting was used to determine the valence-band offset for $\left(\mathrm{ZnMn}\right)\mathrm{Se}$/$\left(\mathrm{ZnBeMg}\right)\mathrm{Se}$ to $0.22$ of the total band-gap discontinuity. Weakly confining multiple quantum wells made of ${\mathrm{Zn}}_{0.91}{\mathrm{Mn}}_{0.09}\mathrm{Se}/{\mathrm{Zn}}_{0.972}{\mathrm{Be}}_{0.028}\mathrm{Se}$ 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.