Spectroscopic imaging in a narrow GaAs quantum well

Spectroscopic images from a narrow GaAs/AlGaAs quantum well obtained with a microscope based on a solid immersion lens are presented. We show that the luminescing excitons are localized in quantum dot-like states but that the y share a common excitation resonance. Excitation images obtained at this e nergy are extended in the plane of the quantum well. With increasing pump p ower density the exciton intensities saturate and biexciton lines are obser ved. Further increasing the pump power leads to the growth of a broad spect ral feature that is ascribed to an electron-hole plasma.