RESONANT RAYLEIGH-SCATTERING IN QUANTUM-WELL STRUCTURES

We report continuous wave experiments on resonant Rayleigh scattering (RRS) performed on high quality GaAs/AlGaAs quantum well structures. T he simultaneous measurement of the resonant Rayleigh scattering and of the photoluminescence excitation (PLE) allows us to resolve very smal l differences between the two spectra. We show that, even in very good samples, there is a small but detectable Stokes shift of the RRS prof ile with respect to the PLE. It is also found that the RRS profile has a smaller linewidth and is sensitive to bound exciton transitions whi ch are not detectable in the PLE. We compare our data with previous fi ndings and discuss possible origins of the Stokes shift.