Misfit dislocations in pseudomorphic In0.23Ga0.77As/GaAs quantum wells: Influence on lifetime and diffusion of excess excitons

Abstract

The recombination dynamics of excess charge carriers around misfit dislocations in strained layer GaAs/In_0.23Ga_0.77As/GaAs quantum wells are directly imaged with spectrally and time‐resolved infrared cathodoluminescence imaging with subnanosecond time resolution. This unique experimental approach for the first time allows the imaging of excitonic lifetime around dislocations in such quantum wells. A strong reduction is observed. The quenching by more than two orders of magnitude of the quantum efficiency upon an increase of the line dislocation density from 4×10³ to 5×10⁶ m⁻¹ is explained quantitatively by a diffusion model. The critical layer thickness is determined to agree well with the ‘‘mechanical equilibrium of forces’’ model.