# Origin of luminescence quenching in structures containing CdSe/ZnSe quantum dots with a few Mn$^{2+}$ ions

## TL;DR

This study investigates the mechanisms behind luminescence quenching in CdSe/ZnSe quantum dots doped with Mn$^{2+}$ ions, revealing that quenching mainly affects the wetting layer and occurs at excited states, not in individual dots.

## Contribution

It provides a detailed spectroscopic analysis showing that Mn$^{2+}$ ions influence overall luminescence but do not quench individual quantum dot emission directly.

## Key findings

- Mn$^{2+}$ ions do not effectively quench individual dot luminescence
- Presence of Mn$^{2+}$ ions significantly quenches wetting layer luminescence
- Luminescence decay dynamics are unaffected by Mn$^{2+}$ ions

## Abstract

We present a detailed spectroscopic study of the photoluminescence quenching in an epitaxial structures containing CdSe/ZnSe quantum dots doped with low concentration of Mn$^{2+}$ ions. Our time-resolved and time-integrated experiments reveal the origin of the quenching observed in macro-photoluminescence studies of ensembles of such dots. We show that incorporation of even a few ions to an individual dot does not quench its luminescence effectively, although some fingerprints of expected spin-dependent quenching are visible. At the same time, the presence of Mn$^{2+}$ ions in the sample significantly affects the luminescence intensity of the wetting layer, resulting in a quenching of the global luminescence from studied structure. On the other hand, the luminescence decay dynamics is found to be independent of the presence of Mn$^{2+}$ ions, which suggests that the observed quenching occurs for the excited excitonic states.