  A theoretical investigation on slow light propagation based on
eletromagnetically induced transparency in a three-level quantum-dot system is
performed including non-Markovian effects and correlated dephasing reservoirs.
It is demonstraonated that the non-Markovian nature of the process is quite
essential even for conventional dephasing typical of quantum dots leading to
significant enhancement or inhibition of the group velocity slow-down factor as
well as to the shifting and distortion of the transmission window. Furthermore,
the correlation between dephasing reservoirs may also either enhance or inhibit
non-Markovian effects.
