Space-charge-mediated capture of electrons and holes in a quantum well

Abstract

Unequal quantum-well capture rates of electrons and holes give rise to the accumulation of space charge which accelerates the capture of electrons and retards the capture of holes. This case is analyzed for the GaAs/${\mathrm{Ga}}_{0.7}$ ${\mathrm{In}}_{0.3}$As single-quantum-well system using two optical-phonon spectra: (a) bulk spectrum in both barrier and well, and (b) bulk spectrum in the barrier, confined hybrids in the well. Phonon confinement reduces the capture rate significantly. Equilibrated resonant capture times for a 50-Å well obtained are for bulk modes and for bulk and/or confined modes.