Size-dependent fine-structure splitting in self-organized InAs/GaAs quantum dots

TL;DR

This study investigates how the exciton fine-structure splitting varies with quantum dot size in InAs/GaAs dots, revealing size-dependent trends and the influence of piezoelectricity, supported by theoretical modeling.

Contribution

It provides the first systematic analysis of size-dependent fine-structure splitting in self-organized InAs/GaAs quantum dots, highlighting piezoelectricity as the key factor.

Findings

Splitting increases from -80 to 520 μeV with size

Sign change of splitting observed in small dots

Piezoelectricity identified as main cause

Abstract

A systematic variation of the exciton fine-structure splitting with quantum dot size in single InAs/GaAs quantum dots grown by metal-organic chemical vapor deposition is observed. The splitting increases from -80 to as much as 520 $\mu$eV with quantum dot size. A change of sign is reported for small quantum dots. Model calculations within the framework of eight-band k.p theory and the configuration interaction method were performed. Different sources for the fine-structure splitting are discussed, and piezoelectricity is pinpointed as the only effect reproducing the observed trend.