Molecular beam epitaxy of wafer-scale O-band InAs/InGaAs quantum dots on GaAs for quantum photonics

TL;DR

This paper presents a scalable molecular beam epitaxy method to produce low-density, electrically tunable InAs/InGaAs quantum dots on GaAs for quantum photonics, enabling single-photon emission within the O-band.

Contribution

The authors develop a novel MBE growth strategy that allows precise control over quantum dot density, position, and emission wavelength for quantum photonics applications.

Findings

Achieved low-density quantum dots (< 1 QD/μm²) on GaAs substrates.

Demonstrated single-photon emission with g(2)(0) = 0.020(14).

Successfully tuned emission wavelength within the O-band using electric fields.

Abstract

We report a scalable molecular beam epitaxy strategy to achieve a low density of O-band electrically tunable InAs/InGaAs quantum dots (QDs) on GaAs(001) substrates. Our approach is based on a gradient deposition of InAs in the sub-ML regime and subsequent capping with an InGaA strain-reducing layer to redshift the emission wavelength. For different growth conditions, we investigate the optical properties of the dots using photoluminescence mapping and correlate with structural properties determined by scanning transmission electron microscopy. Using a surface roughness modulation technique and synchronizing InAs sub-monolayer deposition cycles with substrate rotation, we control the dot density and position low-density regions (< 1 QD per um^2) on the substrate. Hyperspectral imaging is used to map the spatial and spectral characteristics of many individual dots in the low-density region, confirming that our approach is universally applicable to conventional MBE growth on (001) surfaces. Finally, we tune the QD emission wavelength within the O-band using electric fields and demonstrate single-photon emission with g(2)(0) = 0.020(14).