We discuss the decay process of free trions, which differs radically from t
hat of the neutral exciton or localized trions. A theoretical model for the
decay time of free trions shows that due to the three particle decay proce
ss a rapid radiative decay, compared to the neutral exciton, is expected. W
e demonstrate the rapid decay of negatively charged excitons in remotely do
ped GaAs/AlGaAs quantum wells (QW's) experimentally and show the effects of
temperature and well-width on the decay of free negatively charged exciton
s.