Observation of localized above-barrier excitons in type-I superlattices.

This Letter reports experimental evidence for the existence or localized excitons at above-barrier energies in type-I superlattices. By using magnetoabsorption measurement on a series or Zn 0.86 Cd 0.14 -Se/Zn 0.75 Mn 0.25 Se superlattices, where the subbands localized in nonmagnetic and magnetic layers undergo drastically different Zeeman splittings, we show conclusively that above-barrier excitons are localized in the barrier rather than in the well regions