Enhanced radiative recombination of free excitons in GaAs quantum wells

Abstract

Radiative properties of free excitons in a single GaAs quantum well are studied under resonant excitation. Enhanced radiative recombination of the excitons, caused by the breakdown of the translational symmetry of the system, is evidenced by the very short lifetime as well as by the strong intensity of the signal. Dephasing mechanisms, by transferring the excitons to nonradiative states, increase the observed lifetime. We deduce a radiative lifetime of 10\ifmmode\pm\else\textpm\fi{}4 ps in the absence of dephasing mechanisms.