Statistical study of stacked/coupled site-controlled pyramidal quantum dots and their excitonic properties

TL;DR

This study investigates the optical and electronic interactions of stacked site-controlled pyramidal quantum dots, revealing how stacking influences emission energy, polarization, and excitonic charging, with implications for quantum device engineering.

Contribution

It provides a detailed experimental analysis of coupled quantum dots within pyramidal recesses, highlighting the effects of stacking on their excitonic properties and interactions.

Findings

Red-shift of emission energy with increased QD interaction

Change in polarization orientation indicating coupling

Stacked QDs influence excitonic charging behavior

Abstract

We report on stacked multiple quantum dots (QDs) formed inside inverted pyramidal recesses, which allow for the precise positioning of the QDs themselves. Specifically we fabricated double QDs with varying inter-dot distance and ensembles with more than two nominally highly symmetric QDs. For each, the effect of the interaction between QDs is studied by characterizing a large number of QDs through photoluminescence spectroscopy. A clear red-shift of the emission energy is observed together with a change in the orientation of its polarization, suggesting an increasing interaction between the QDs. Finally we show how stacked QDs can help influencing the charging of the excitonic complexes.