EXCITON RADIATIVE DECAY AND HOMOGENEOUS BROADENING IN CDTE/CD0.85MN0.15TE MULTIPLE-QUANTUM WELLS

Exciton resonances are observed in the room-temperature absorption and photoluminescence (PL) spectra of CdTe/Cd0.85Mn0.15Te 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 (GAMMA(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 GAMMA(H)/r(T), where r(T) is the fraction of excitons with transition frequencies in GAMMA(H). From 170 K nonradiative processes dominate the decay so that the PL decay time decreases with temperature.