Polarons in semiconductor quantum-dots and their role in the quantum kinetics of carrier relaxation

TL;DR

This paper demonstrates that quantum kinetic modeling reveals rapid carrier relaxation in semiconductor quantum dots due to polaron effects, contrasting with predictions from time-dependent perturbation theory.

Contribution

It introduces a quantum kinetic approach to accurately describe carrier-phonon interactions in quantum dots, highlighting the role of polarons in carrier relaxation.

Findings

Quantum kinetic theory predicts fast carrier relaxation.

Polar coupling significantly alters energy conservation in quantum dots.

Time-dependent perturbation theory underestimates relaxation rates.

Abstract

While time-dependent perturbation theory shows inefficient carrier-phonon scattering in semiconductor quantum dots, we demonstrate that a quantum kinetic description of carrier-phonon interaction predicts fast carrier capture and relaxation. The considered processes do not fulfill energy conservation in terms of free-carrier energies because polar coupling of localized quantum-dot states strongly modifies this picture.