Defect related recombination processes in II-VI quantum wells

Results of photoluminescence (PL), PL excitation, PL transients and optically detected cyclotron resonance (ODCR) experiments are presented for unintentionally doped multi quantum well (MQW) structures of CdTe/CdMnTe, CdTe/CdMgTe and ZnCdSe/ZnSe. We show that donor-type shallow impurities contribute to the PL emission from undoped quantum wells (QWs) of the MQW structures. The PL emission of a neutral donor bound exciton (DBE) is identified and the origin of the donor species in CdTe and ZnCdSe QWs is discussed. The ODCR experiments indicate that these donor impurities limit the mobility of two dimensional (2D) carriers. We show also that the energy transfer between the localized excitons and the donor bound excitons is not efficient.