Combined exciton and trion excitations in modulation doped quantum well structures

Photoluminescence, photoluminescence excitation (PLE) and reflectivity spectra of CdTe-based modulation-doped quantum well (QW) structures with 2DEG have been studied in magnetic fields. Resonant lines corresponding to combined optical transitions in which the photo-generation of excitons as well as trions is accompanied by the excitation of an additional electron from states below the Fermi level to states above the Fermi level were observed and analyzed.