Excitation mechanisms of individual CdTe/ZnTe quantum dots studied by photon correlation spectroscopy

TL;DR

This study investigates how individual CdTe/ZnTe quantum dots emit photons under pulsed excitation, revealing non-resonant excitation mechanisms, memory effects, and the significance of single carrier trapping through photon correlation spectroscopy.

Contribution

It provides a detailed analysis of excitation mechanisms and introduces a rate equation model to explain correlation and photoluminescence data in quantum dots.

Findings

Memory effects persist over several excitation pulses.

Single carrier trapping significantly influences emission.

A new explanation for wide antibunching dips in autocorrelation was proposed.

Abstract

Systematic measurements of auto- and cross-correlations of photons emitted from individual CdTe/ZnTe quantum dots under pulsed excitation were used to elucidate non-resonant excitation mechanisms in this self-assembled system. Memory effects extending over a few excitation pulses have been detected in agreement with previous reports and quantitatively described by a rate equation model, fitting a complete set of correlation and PL intensity results. The important role of single carrier trapping in the quantum dot was established. An explanation was suggested for the unusually wide antibunching dip observed previously in X-X autocorrelation experiments on quantum dots under cw excitation.