Electron capture in quantum wells via scattering by electrons, holes, and optical phonons.

Abstract

Electron capture times due to the electron-electron (e-e), electron-hole (e-h) and electron-polar optical phonon (e-pop) interactions are calculated in the GaAs quantum well (QW) with electron and hole densities 10^11 cm^-2. The calculated capture times oscillate as a function of the QW width with the same period but with different amplitudes. The e-h capture time is two to four orders larger and the e-e capture time one to three orders larger than the e-pop capture time. The exceptions are the QW widths near resonance minima, where the e-e capture time is only 2-3 times larger and the e-h capture time 10-100 times larger. Different physical origin of the oscillatory behavior is demonstrated for the e-e and e-pop capture times. Effects of exchange and degeneracy on the e-e capture are analysed. The exchange effect increases the e-e capture time approximately two times while the degeneracy does not change the capture time except for the QW depths and widths near the resonance.