Competition between radiative decay and energy relaxation of carriers in disordered InxGa1-xAs/GaAs quantum wells

Photoluminescence (PL) and excitation PL measurements have been performed a t different temperatures, excitation energies, and power densities in a num ber of strained InxGa1-xAs quantum wells where the fluctuations in the pote ntial energy were comparable with the thermal energy. This has allowed us t o observe a full series of anomalous temperature dependencies. These featur es, including some subtle ones, follow from the competition of thermalizati on and the degree of disorder in the samples. They are all accounted for by a theoretical model, which takes into account the excitons' radiative deca y and phonon scattering in a disordered potential on an equal footing. Thus the interplay between finite lifetime and relaxation/thermalization is inc luded in detail.