  Electron relaxation in quantum dots is studied theoretically in polar
semiconductor materials, with an emphasis put on the phonon-bottleneck problem
and electron-LO-phonon coupling. The theory is based on multiphonon states of
the electron-LO-phonon system and the self-consistent Tamm-Dancoff
approximation is used for the electronic self-energy. Electronic relaxation
rate is shown numerically to be on the scale from hundreds fs to tens ps, for
electron energy-level separations being in the broad range from about one
LO-phonon energy to about three or four optical-phonon energies. Despite of
displaying some resonance features, the electronic relaxation rate does not
appear to be crucially dependent on the quantum dot size.
