Sensitivity of Exciton Spin Relaxation in Quantum Dots to Confining Potential

TL;DR

This study investigates how the exciton spin relaxation time in CdTe quantum dots varies with dot size and confining potential, revealing that larger dots with weaker confinement exhibit faster spin relaxation.

Contribution

It demonstrates the dependence of exciton spin relaxation on quantum dot size and confinement, highlighting the impact of thermal annealing on spin dynamics in CdTe quantum dots.

Findings

Spin relaxation time decreases from 4.8 ns to 1.5 ns after annealing.

Larger quantum dots show increased mixing between spin states.

Annealing enhances spin scattering efficiency.

Abstract

We observe a strong dependence of the exciton spin relaxation in CdTe quantum dots on the average dot size and the depth of the confining potential. For the excitons confined to the as-grown CdTe quantum dots we find the spin relaxation time to be 4.8 ns. After rapid thermal annealing, which increases the average dot size and leads to weaker confinement, we measure the spin relaxation tine to be 1.5 ns, resulting in smaller values of the absolute polarization of the quantum dot emission. This dramatic enhancement of the spin scattering efficiency upon annealing is attributed to increased mixing between different spin states in larger CdTe quantum dots.