Phonon-induced electron relaxation in weakly-confined single and coupled quantum dots

TL;DR

This paper studies how acoustic phonons cause charge relaxation in weakly-confined quantum dots, identifying dominant mechanisms and proposing design strategies to extend electron lifetimes to microseconds.

Contribution

It provides detailed calculations of electron relaxation rates considering both deformation potential and piezoelectric interactions in various quantum dot configurations, highlighting ways to optimize structures.

Findings

Piezoelectric scattering often dominates relaxation processes.

Structural design can significantly extend electron lifetimes.

Electron lifetimes up to microseconds are achievable.

Abstract

We investigate charge relaxation rates due to acoustic phonons in weakly-confined quantum dot systems, including both deformation potential and piezoelectric field interactions. Single-electron excited states lifetimes are calculated for single and coupled quantum dot structures, both in homonuclear and heteronuclear devices. Piezoelectric field scattering is shown to be the dominant relaxation mechanism in many experimentally relevant situations. On the other hand, we show that appropriate structure design allows to minimize separately deformation potential and piezolectric field interactions, and may bring electron lifetimes in the range of microseconds.