INTERSUBBAND AND INTRASUBBAND RELAXATION OF HOT CARRIERS IN QUANTUM-WELLS PROBED BY TIME-RESOLVED RAMAN-SPECTROSCOPY

Anti-Stokes Raman scattering has been used to investigate hot carrier dynamics in GaAs/AlGaAs quantum wells and has revealed new information on the physics of the electron-phonon interaction. Measurements of in ter-subband relaxation have for the first time revealed sub-picosecond scattering rates. Also, it has been demonstrated that intra-subband r elaxation in narrow quantum wells is dominated by the emission of inte rface modes. Furthermore, the lifetime of LO phonons in quantum wells is found to be smaller than in bulk GaAs.