Localization induced electron-hole transition rate enhancement in GaAs quantum wells

Abstract

The transition rate of excitonic e-h recombination in GaAs quantum wells is found to increase by almost one order of magnitude upon a decrease of the well width from infinity to 52 Å due to increased excitonic localization. Competing capture of free carriers by impurities is increasingly suppressed. Time delayed cathodoluminescence spectra and decay times taken at 5-300 K show this unambiguously. Transfer of carriers from 176-Å Ga 0.6Al0.4As cladding wells is found to occur ballistically in 10-13 s.