Carrier relaxation mechanisms in self-assembled (In,Ga)As/GaAs quantum dots: Efficient P -> S Auger relaxation of electrons

TL;DR

This study calculates electron relaxation times in (In,Ga)As/GaAs quantum dots, showing that Auger electron-hole scattering causes rapid P-to-S shell decay within 1-7 ps, aligning with experimental data.

Contribution

It provides a detailed atomistic calculation of Auger relaxation times, demonstrating their sufficiency in explaining electron decay without alternative mechanisms.

Findings

Relaxation times are 1-7 ps across various dot sizes.

Auger scattering explains decay without needing polaron effects.

Calculated lifetimes match experimental observations.

Abstract

We calculate the P-shell--to-S-shell decay lifetime \tau(P->S) of electrons in lens-shaped self-assembled (In,Ga)As/GaAs dots due to Auger electron-hole scattering within an atomistic pseudopotential-based approach. We find that this relaxation mechanism leads to fast decay of \tau(P->S)~1-7 ps for dots of different sizes. Our calculated Auger-type P-shell--to-S-shell decay lifetimes \tau(P->S) compare well to data in (In,Ga)As/GaAs dots, showing that as long as holes are present there is no need for an alternative polaron mechanism.