  We calculate the lifetime of conduction band excited states in self-assembled
quantum dots by taking into account LO-phonon-electron interaction and various
anharmonic phonon couplings. We show that polaron relaxation cannot be
accurately described by a semi-classical model. The contributions of different
anharmonic decay channels are shown to depend strongly on the polaron energy.
We calculate the energy dependence of polaron lifetime and compare our results
to available experimental measurements of polaron decay time in InAs/GaAs
quantum dots.
