Comparison of magneto-optical properties of various excitonic complexes in CdTe and CdSe self-assembled quantum dots

TL;DR

This study compares the magneto-optical properties of excitonic complexes in CdTe and CdSe quantum dots, revealing differences in energy, fine-structure splitting, g-factors, and diamagnetic shifts through systematic single-dot photoluminescence analysis.

Contribution

It provides a detailed comparative analysis of excitonic complexes in CdTe and CdSe quantum dots, highlighting key differences in their magneto-optical parameters.

Findings

CdTe QDs have a 12 meV X-XX transition energy difference; CdSe QDs have 24 meV.

Fine-structure splitting is smaller in CdTe (0.14 meV) than in CdSe (0.47 meV).

g-factors are higher in CdTe (2.12) compared to CdSe (1.71).

Abstract

We present a comparative study of two self-assembled quantum dot (QD) systems based on II-VI compounds: CdTe/ZnTe and CdSe/ZnSe. Using magneto-optical techniques we investigated a large population of individual QDs. The systematic photoluminescence studies of emission lines related to the recombination of neutral exciton X, biexciton XX, and singly charged excitons (X$^+$, X$^-$) allowed us to determine average parameters describing CdTe QDs (CdSe QDs): X-XX transition energy difference 12 meV (24 meV); fine-structure splitting $\delta_{1}=$0.14 meV ($\delta_{1}=$0.47 meV); $g$-factor $g=$2.12 ($g=$1.71); diamagnetic shift $\gamma=$2.5 $\mu$eV$/$T$^{2}$ ($\gamma=$1.3 $\mu$eV$/$T$^{2}$). We find also statistically significant correlations between various parameters describing internal structure of excitonic complexes.