Exciton Footprint of Self-assembled AlGaAs Quantum Dots in Core-Shell Nanowires

TL;DR

This study investigates the electronic symmetry and excitonic properties of gallium-rich quantum dots within GaAs-AlGaAs core-shell nanowires, revealing their potential for advanced photonic applications due to their unique exciton footprints and charge hosting capabilities.

Contribution

The paper provides detailed optical spectroscopy analysis of quantum dots in nanowires, highlighting their excitonic structures and the impact of their elongated footprints, which is a novel insight for nanowire-based quantum emitters.

Findings

Quantum dots can host neutral and charged excitonic complexes.

Excitons exhibit a slightly elongated footprint with a tilted main axis.

GaAs-AlGaAs nanowire emitters can overcome strain limitations in other systems.

Abstract

Quantum-dot-in-nanowire systems constitute building blocks for advanced photonics and sensing applications. The electronic symmetry of the emitters impacts their function capabilities. Here, we study the fine structure of gallium-rich quantum dots nested in the shell of GaAs-AlGaAs core-shell nanowires. We used optical spectroscopy to resolve the splitting resulting from the exchange terms and extract the main parameters of the emitters. Our results indicate that the quantum dots can host neutral as well as charges excitonic complexes and that the excitons exhibit a slightly elongated footprint, with the main axis tilted with respect to the growth axis. GaAs-AlGaAs emitters in a nanowire are particularly promising for overcoming the limitations set by strain in other systems, with the benefit of being integrated in a versatile photonic structure.