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

## TL;DR

Researchers developed a method to precisely control the position and density of quantum dots for use in quantum photonics.

## Contribution

A two-step epitaxial growth method enables site-controlled InGaAs quantum dots with local density variation.

## Key findings

- Buried-stressor apertures achieve low lateral displacement of quantum dots.
- Theoretical calculations explain stressor aperture effects on quantum dot properties.
- Reproducible nucleation of quantum dots is achieved within a single growth step.

## 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
17−17+19nm
from
the mesa centers. We provide extensive
microphotoluminescence 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 the site-controlled quantum dots, paving the way for highly functional
source modules with applications in photonic quantum technology.