Buried Stressor Engineering for Position-Controlled InGaAs Quantum Dots with Local Density Variation for Integrated Quantum Photonics

TL;DR

This paper demonstrates a precise, monolithic growth method for site-controlled InGaAs quantum dots with variable densities, enabling integrated quantum photonic devices with high accuracy and reproducibility.

Contribution

It introduces a novel buried stressor technique for site-controlled quantum dot fabrication with local density variation and high positional accuracy.

Findings

Achieved low lateral displacement of stressor apertures (~17 nm)

Demonstrated reproducible nucleation of quantum dots with different densities

Showed potential for integrated quantum photonic applications

Abstract

We report on the monolithic, two-step epitaxial growth of site-controlled InGaAs quantum dots via the buried stressor method with local quantum dot density variation. As a result of high fabrication accuracy, we achieve low lateral displacements of the individual buried stressor apertures of $ 17^{+19}_{-17}$~nm from mesa centers. We provide extensive micro-photoluminescence and cathodoluminescence characterization of the site-controlled quantum dots and give theoretical calculations, explaining the effect of the stressor aperture on the quantum dot emission properties, positioning, and density. We show reproducibility of the nucleation process for apertures of the same size and achieve precisely-positioned, low- and high-density quantum dot nucleation within one active layer growth step. The results presented in this work demonstrate the significant potential of the buried stressor concept in fabricating single photonic chips, simultaneously combining single-photon sources and microlasers featuring different local densities of site-controlled quantum dots, paving the way for highly functional source modules with applications in photonic quantum technology.