Electron capture in GaAs quantum wells via electron-electron and optic phonon scattering

TL;DR

This study calculates electron capture times in GaAs quantum wells due to electron-electron and optic phonon scattering, revealing oscillatory behavior with well width and density-dependent variations, challenging previous assumptions.

Contribution

It provides new calculations of electron capture times considering both scattering mechanisms, showing their oscillatory dependence on well width and electron density effects.

Findings

Electron capture times oscillate with quantum well width.

Electron-electron capture times are significantly larger than phonon capture times.

Increased electron density reduces electron-electron capture times.

Abstract

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.