Intersubband relaxation of heavy-hole excitons in GaAs quantum wells

Abstract

The temporal dynamics of an exciton in a higher quantum-well subband is observed. The lifetime of the exciton formed by an electron of the lowest subband and a heavy hole of the second subband in GaAs quantum wells is determined by time-resolved luminescence as 130\ifmmode\pm\else\textpm\fi{}20 ps, in agreement with theoretical estimations of intersubband scattering by acoustic-phonon emission. Consequences for intersubband lasers are substantial.