# Light / heavy hole switching with correlated characterization on a single quantum dot : Probing the light hole / heavy hole switching with correlated magneto-optical spectroscopy and chemical analysis on a single quantum dot

## TL;DR

This study combines multiple spectroscopic and chemical analysis techniques on a single quantum dot to investigate the switching between light-hole and heavy-hole states, revealing the influence of strain, shape, and shell composition.

## Contribution

It provides a comprehensive, correlated characterization of a single quantum dot, demonstrating how strain, shape, and shell composition affect hole state switching.

## Key findings

- Heavy-hole state is the ground state in the quantum dot.
- Aspect ratio influences the transition from heavy-hole to light-hole states.
- Shell composition and valence band offset modify the hole state configuration.

## Abstract

A whole series of complementary studies have been performed on the same, single nanowire containing a quantum dot: cathodoluminescence spectroscopy and imaging, micro-photoluminescence spectroscopy under magnetic field and as a function of temperature, and energy-dispersive X-ray spectrometry and imaging. The ZnTe nanowire was deposited on a Si 3 N 4 membrane with Ti/Al patterns. The complete set of data shows that the CdTe quantum dot features the heavy-hole state as a ground state, although the compressive mismatch strain promotes a light-hole ground state as soon as the aspect ratio is larger than unity (elongated dot). A numerical calculation of the whole structure shows that the transition from the heavy-hole to the light-hole configuration is pushed toward values of the aspect ratio much larger than unity by the presence of a (Zn,Mg)Te shell, and that the effect is further enhanced by a small valence band offset between the semiconductors in the dot and around it.