Excitonic magnetic polaron dynamics of MBE grown CdTe/Cd1-xMnxTe, Cd1-xMnxTe/Cd1-yMgyTe single quantum wells in magnetic fields

Excitonic lifetimes in Cd1-xMnxTe, Cd1-xMgxTe epilayers and CdTe/Cd1-xMnxTe, Cd1-xMnxTe/Cd1-yMgyTe single quantum wells with different well widths and Mn, Mg compositions are investigated. The excitonic lifetimes are found to reduce drastically by applying external magnetic fields to samples with giant Zeeman splittings. The observed phenomenon is interpreted in terms of the PL decay time contribution from the long-life dark excitons which can convert to excitons for recombinations by a spin-flip process. We attribute the lifetime reduction to the depletion of dark excitons due to their crossing over the exciton energies for dipole allowed transitions in magnetic fields. (C) 1999 Academic Press.