Exciton radiative decay and homogeneous broadening in CdTe/${\mathrm{Cd}}_{0.85}$${\mathrm{Mn}}_{0.15}$Te multiple quantum wells

Exciton resonances are observed in the room-temperature absorption and photoluminescence (PL) spectra of CdTe/${\mathrm{Cd}}_{0.85}$${\mathrm{Mn}}_{0.15}$Te multiple-quantum-well structures. Temperature-dependent absorption linewidth and PL decay measurements are reported. Above 45 K, exciton-LO-phonon scattering determines the homogeneous linewidth (${\mathrm{\Gamma }}_{\mathit{H}}$). High excitation intensities were used in the PL decay measurements so that delocalized excitons were created. The PL decay time is found to be a measure of the exciton radiative decay time between 45 and 145 K and it increases linearly with ${\mathrm{\Gamma }}_{\mathit{H}}$/r(T), where r(T) is the fraction of excitons with transition frequencies in ${\mathrm{\Gamma }}_{\mathit{H}}$. From 170 K nonradiative processes dominate the decay so that the PL decay time decreases with temperature.