Magneto-Excitons in CdTe/(CdMn)Te Quantum Wells

We have performed low temperature photoluminescence and photoluminescence excitation measurements on CdTe/(CdMn)Te single quantum wells in magnetic fields up to 9.5 T. The analysis of the temperature and magnetic field dependence of the splitting of the heavy-hole exciton in Faraday configuration shows that the splitting of the exciton in the nonmagnetic layer is caused by exchange interaction with the Mn++ ions in the barrier. From the asymmetric behaviour of the splitting of the heavy-hole excitonic recombination we identify a Type-I to Type-II transition of heterostructures with small manganese concentration in the barrier. The asymmetric splitting furthermore allows to determine the valence band offset to 20 ± 5 % of the total bandgap discontinuity. In addition we deduce from the finestructure of the spectra the binding energy of the heavy-hole exciton as a function of the well width.