In-plane radiative recombination channel of a dark exciton in self-assembled quantum dots

TL;DR

This paper provides experimental evidence for an in-plane radiative recombination channel of dark excitons in self-assembled quantum dots, revealing a new decay pathway influenced by light hole admixture and polarization properties.

Contribution

It demonstrates the existence of an in-plane radiative recombination channel of dark excitons due to light hole admixture, confirmed by direct photoluminescence observation and polarization analysis.

Findings

Dark excitons exhibit in-plane radiative recombination.

Photon emission occurs perpendicular to the growth axis.

Radiative decay dominates dark exciton lifetime in studied quantum dots.

Abstract

We demonstrate evidence for a radiative recombination channel of dark excitons in self-assembled quantum dots. This channel is due to a light hole admixture in the excitonic ground state. Its presence was experimentally confirmed by a direct observation of the dark exciton photoluminescence from a cleaved edge of the sample. The polarization resolved measurements revealed that a photon created from the dark exciton recombination is emitted only in the direction perpendicular to the growth axis. Strong correlation between the dark exciton lifetime and the in-plane hole g-factor enabled us to show that the radiative recombination is a dominant decay channel of the dark excitons in CdTe/ZnTe quantum dots.