Efficient single-photon emission via quantum-confined charge funneling to quantum dots
Published in Communications Materials, 2025
Abstract:
Quantum light sources, particularly single-photon emitters (SPEs), are critical for quantum communications and computing. Among them, III-V semiconductor quantum dots (QDs) have demonstrated superior SPE metrics, including near-unity brightness, high photon purity, and indistinguishability, making them especially suitable for quantum applications. However, their overall quantum e ciency—determined by a product of the internal, excitation, and out-coupling e ciencies—remains limited, primarily due to low (typically below 0.1%) excitation e ciency. This has hindered their applications in quantum information systems, including for multi-photon cluster state generation and Boson sampling. To mitigate the low excitation e ciency, here we realized liquid droplet etched GaAs QDs in a microscale 3D AlGaAs charge-carrier funnel using molecular beam epitaxy. The funnel channels charge carriers to the QD and enhances the overall emission e ciency by over one order of magnitude while preserving the SPE behavior. We reveal that a modi ed energy landscape around the QD leads to the excitation e ciency improvement. These energy landscape-modi ed QDs can be operated with optical excitation up to 10 µm away from the QD, raising the promise of e cient and scalable electrically driven epitaxial QD SPE for quantum information systems.