  Electron capture times in a separate confinement quantum well (QW) structure
with finite electron density are calculated for electron-electron (e-e) and
electron-polar optic phonon (e-pop) scattering. We find that the capture time
oscillates as function of the QW width for both processes with the same period,
but with very different amplitudes. For an electron density of 10^11 cm^-2 the
e-e capture time is 10-1000 times larger than the e-pop capture time except for
QW widths near the resonance minima, where it is only 2-3 times larger. With
increasing electron density the e-e capture time decreases and near the
resonance becomes smaller than the e-pop capture time. Our e-e capture time
values are two-to-three orders of magnitude larger than previous results of
Blom et al. [Appl. Phys. Lett. 62, 1490 (1993)]. The role of the e-e capture in
QW lasers is therefore readdressed.
