Picosecond charge variation of quantum dots under pulsed excitation

TL;DR

This study investigates the ultrafast charge dynamics in individual CdTe/ZnTe quantum dots under pulsed excitation, revealing separate and delayed capture of electrons and holes through advanced spectroscopic techniques.

Contribution

It provides new insights into charge capture kinetics in quantum dots using time-resolved spectroscopy, highlighting charge separation and delay phenomena.

Findings

Electrons and holes are captured separately in quantum dots.

Charge capture occurs at different delays after excitation.

Pulsed excitation above the barrier energy influences charge dynamics.

Abstract

We present a spectroscopic study of excitation dynamics in self assembled CdTe/ZnTe quantum dots. Insight into details of kinetics is obtained from the time resolved micro-photoluminescence, single photon correlation and subpicosecond excitation correlation measurements done on single quantum dots. It is shown that the pulsed excitation in energy above the energy gap of the barrier material results in separate capture of electrons and holes. The capture of carriers of different charge take place at different delay from excitation.