Dynamics of charged excitons in GaAs quantum wells under high magnetic field

We report on time-resolved photoluminescence studies of charged and neutral excitons in a modulation doped GaAs quantum well under resonant excitation and high magnetic held. The radiative lifetime of the charged exciton is r ather short, 60 ps at zero held, and is found to increase by a factor of si milar to 2 up to 7 T. The short lifetimes suggest that, under magnetic fiel d, the exciton bound in the trion is delocalized. (C) 1998 Elsevier Science B.V. All rights reserved.