Increase of charge-carrier redistribution efficiency in a laterally organized superlattice of coupled quantum dots

Abstract

We report the observation of enhanced charge-carrier redistribution in laterally organized and coupled $\mathrm{In}\mathrm{As}∕\mathrm{In}\mathrm{P}$ quantum dots (QDs). We show that a periodic organization appears in the QD plane for a high in-plane QD density (QDD). This organization enhances the lateral coupling between the dots, which is evidenced by photoluminescence and magnetophotoluminescence experiments. Electronic inter-QD lateral coupling results in an improved charge-carrier distribution at low temperature, as shown by electroluminescence on high QDD QD lasers. We conclude that the inter-QD tunneling occurs via the tunneling of excited states through the wetting layer, and discuss the prospects of using coupled QDs for improving the quantum efficiency and dynamical properties of QD lasers.