Ultrafast Dynamics of Carrier Multiplication in Quantum Dots

TL;DR

This paper presents a quantum-kinetic model for ultrafast carrier multiplication in semiconductor quantum dots, revealing a transition in behavior influenced by light pulse duration and Coulomb interactions, enabling new detection methods.

Contribution

It introduces a novel quantum-kinetic approach to study ultrafast carrier dynamics and identifies a transition in carrier multiplication behavior based on interaction and pulse timescales.

Findings

Transition between different carrier multiplication behaviors

Detection of carrier multiplication without exciton lifetime measurements

Influence of pulse duration and Coulomb interaction on dynamics

Abstract

A quantum-kinetic approach to the ultrafast dynamics of carrier multiplication in semiconductor quantum dots is presented. We investigate the underlying dynamics in the electronic subband occupations and the time-resolved optical emission spectrum, focusing on the interplay between the light-matter and the Coulomb interaction. We find a transition between qualitatively differing behaviors of carrier multiplication, which is controlled by the ratio of the interaction induced time scale and the pulse duration of the exciting light pulse. On short time scales, i.e., before intra-band relaxation, this opens the possibility of detecting carrier multiplication without refering to measurements of (multi-)exciton lifetimes.