High-Purity Single-Photon Emission in Near-Infrared InAs Colloidal Quantum Dots with Strong Exciton Confinement

Colloidal quantum dots (QDs) are promising solid-state single-photon emitters for quantum information processing due to their facile integration with nanophotonic components and cost-effective production. However, research on near-infrared QDs-based single-photon emitters for telecommunications remains limited. Here, we present bright near-infrared InAs/InP/ZnSe/ZnS QDs that achieve high-purity single-photon emission through strong exciton confinement within the core. Single-QD measurements reveal that this confinement enables ultrafast biexciton Auger recombination, suppressing multiphoton generation and resulting in g⁽²⁾(0) values as low as 0.032 at room temperature. Unlike extensively studied Cd-based QDs with quasi-type II band alignment, which suffer from a trade-off between single-photon purity and blinking suppression, our QDs leverage a thick insulating ZnSe shell to minimize photoluminescence blinking by shielding photogenerated excitons from surface interactions without compromising single-photon purity. This study offers a viable strategy for achieving stable, high-purity single-photon emission in near-infrared QDs, highlighting their potential as heavy-metal-free quantum light sources for telecommunications applications.