Competition between radiative decay and energy relaxation of carriers in disordered ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{A}\mathrm{s}/\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}$ quantum wells

Photoluminescence (PL) and excitation PL measurements have been performed at different temperatures, excitation energies, and power densities in a number of strained ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ quantum wells where the fluctuations in the potential energy were comparable with the thermal energy. This has allowed us to observe a full series of anomalous temperature dependencies. These features, including some subtle ones, follow from the competition of thermalization and the degree of disorder in the samples. They are all accounted for by a theoretical model, which takes into account the excitons’ radiative decay and phonon scattering in a disordered potential on an equal footing. Thus the interplay between finite lifetime and relaxation/thermalization is included in detail.