Energy relaxation of localized excitons at finite temperature

Macro- and micro-photoluminescence (PL) spectroscopy has been applied to investigate the exciton localization in cubic CdS/ZnSe type-II superlattices (SL) in the temperature range 5-35 K. The non-monotonic shift of the macro-PL peak with increasing temperature reveals the kinetic contribution of acoustic-phonon-assisted exciton multi-hopping processes. The experimental data are described by means of computer simulation and calculations based on a kinetic theory generalized from zero to finite temperatures. The advantages of each theoretical approach are discussed.