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arXiv:2608.24495

AlGaAs nanowires as a universal platform for GaAs, InGaAs, and InAs quantum dots

Rohan Radhakrishnan, Rodion Reznik, Gilles Patriarche, Igor Ilkiv, Konstantin Kotlyar, Anna Andreeva, George Cirlin, Nika Akopian

physics.opticscond-mat.mes-hallquant-phSubmitted Aug 25, 2026• Announced Aug 26, 2026
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Abstract

Optical quantum dots (QDs) are central to photonic quantum technologies, with fabrication approaches tailored to different spectral ranges. A key challenge, however, is the realization of a unified platform$\unicode{x2014}$a single growth method combined with a host material offering a designable architecture$\unicode{x2014}$enabling wavelength tunability across the full emission range and co-integration of multiple quantum dots. Here, we introduce AlGaAs nanowires as a universal host for GaAs, InGaAs, and InAs QDs. Building on our previous demonstration of high-quality GaAs QDs, we realize InGaAs QDs with tunable emission by varying the growth duration from 2 to 5 s, achieving emission at 780 and 920 nm. We further showcase the platform's versatility for multi-quantum-dot devices by co-integrating two InGaAs QDs, as well as GaAs and InGaAs QDs within a single nanowire. Finally, we initiate a first step toward pure InAs QDs by growing a pristine InAs segment on AlGaAs nanowires, demonstrating material compatibility.

Comments
Main text: 18 pages, 4 figures / Supplementary Materials: 24 pages, 12 figures

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Optical quantum dots (QDs) are central to photonic quantum technologies, with fabrication approaches tailored to different spectral ranges. A key challenge, however, is the realization of a unified platform\unicodex2014\unicode{x2014}\unicodex2014a single growth method combined with a host material offering a designable architecture\unicodex2014\unicode{x2014}\unicodex2014enabling wavelength tunability across the full emission range and co-integration of multiple quantum dots. Here, we introduce AlGaAs nanowires as a universal host for GaAs, InGaAs, and InAs QDs. Building on our previous demonstration of high-quality GaAs QDs, we realize InGaAs QDs with tunable emission by varying the growth duration from 2 to 5 s, achieving emission at 780 and 920 nm. We further showcase the platform's versatility for multi-quantum-dot devices by co-integrating two InGaAs QDs, as well as GaAs and InGaAs QDs within a single nanowire. Finally, we initiate a first step toward pure InAs QDs by growing a pristine InAs segment on AlGaAs nanowires, demonstrating material compatibility.
Semiconductor quantum dots (QDs) are a leading platform for realising bright, wavelength-tunable sources of single and entangled photon pairs for photonic quantum technologies. Site-selected nanowire quantum dots (NWQDs) are a promising platform for fabricating such photonic devices in a scalable manner. However, implementing additional structures around the photonic nanowire while maintaining its vertical growth geometry has remained a challenge. In this work, we develop a deterministic pick-and-place technique to conduct a vertical-to-vertical transfer of NWQDs from the growth substrate to arbitrary templates. Using this transfer technique, we enhance the photon extraction efficiency to 75% by implementing a bottom gold mirror and tune the emission wavelength by 3.6 GHz via implementing electrostatic gates around the QD. Importantly, we measure low-multiphoton probability (g^(2)(0) = 0.002) and high indistinguishability (>80% for +/-100 ps) of the QD emission after the transfer process, yielding high-quality devices. These results demonstrate the repeatability and versatility of the developed transfer technique, which is an enabling step towards scalable single and entangled photon sources.
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Semiconductor quantum dots (QDs) have emerged as a premier solid-state platform for the deterministic generation of nonclassical light, offering a compelling pathway toward scalable quantum photonic systems. While single-photon emission from QDs has reached a high level of maturity, the realization of high-fidelity entangled photon-pair sources remains an active and rapidly evolving frontier. In this review, we survey the recent progress in QD-based entangled photon sources, highlighting the conceptual evolution from the established biexciton-exciton cascade to the emerging paradigm of spontaneous two-photon emission. We further examine how advances in nanophotonic architectures and coherent control strategies are redefining fundamental performance limits, enabling concurrent improvements in source brightness, coherence, and entanglement fidelity. Finally, we discuss the key physical and technological challenges that must be addressed to bridge the gap between laboratory demonstrations and large-scale deployment. We conclude by outlining the future opportunities for integrating QD-based entangled photon sources into practical quantum communication, computation, and sensing platforms.
Semiconductor quantum dots (QDs) have emerged as a premier solid-state platform for the deterministic generation of nonclassical light, offering a compelling pathway toward scalable quantum photonic systems. While single-photon emission from QDs has reached a high level of maturity, the realization of high-fidelity entangled photon-pair sources remains an active and rapidly evolving frontier. In this review, we survey the recent progress in QD-based entangled photon sources, highlighting the conceptual evolution from the established biexciton–exciton cascade to the emerging paradigm of spontaneous two-photon emission. We further examine how advances in nanophotonic architectures and coherent control strategies are redefining fundamental performance limits, enabling concurrent improvements in source brightness, coherence, and entanglement fidelity. Finally, we discuss the key physical and technological challenges that must be addressed to bridge the gap between laboratory demonstrations and large-scale deployment. We conclude by outlining the future opportunities for integrating QD-based entangled photon sources into practical quantum communication, computation, and sensing platforms.
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