Influence of the exciton lifetime on resonant Raman scattering in quantum wells

We report huge enhancements in the intensity of LO Raman scattering for photon energies resonant with the band-edge exciton of GaAs/AlAs multiple quantum wells, due to a sharpening of the resonance caused by the increased exciton phase-coherence lifetime. This explains the redshift of the resonance Raman profile with respect to the absorption, the much stronger heavy-hole resonance than that of the light-hole resonance, and the rapid decline of Raman intensity with temperature.