Influence of exciton diffusion and localization on cathodoluminescence imaging of quantum well structures

Publisher Website
Google Scholar
Abstract
The effect of exciton diffusion and localization on the cathodoluminescence (CL) intensity distribution using a scanning electron microscope has been investigated in a single quantum well and a multiple quantum well structure prepared by growth interrupted molecular beam epitaxy. Although of different origin, lateral variations of the exciton confinement energy occur in both samples on a length scale much larger than the exciton Bohr radius. The spectral and spatial CL intensity distribution is substantially influenced by diffusion of excitons to quantum well regions with low exciton confinement energy. The CL micrographs from both quantum well structures exhibit a similar bright/dark pattern with a typical length scale, which is determined by the exciton diffusion length in this material.