Photoluminescence studies of pseudomorphic modulation‐doped AlGaAs/InGaAs/GaAs quantum wells

We discuss the photoluminescence (PL) properties of pseudomorphic modulation‐doped Al0.15Ga0.85As/In0.2Ga0.8As/GaAs quantum wells as a function of temperature. At 4.2 K, hole localization influences the PL linewidth; however, at higher temperatures (77 K) the thermal energy of photoexcited holes is sufficiently large to obtain a reliable measure of sheet carrier density from the PL linewidth. Our results also suggest that information about the interface quality can be obtained from an analysis of the PL linewidth at 77 and 4.2 K. The spectra taken from several samples clearly show that the PL transition energy exhibits a free‐carrier density dependence due to band‐gap renormalization and electric field effects.