Broadband Telecom Single-Photon Emissions from InAs/InP Quantum Dots Grown by MOVPE Droplet Epitaxy

Abstract The development of quantum materials for single-photon emission is crucial for the advancement of quantum information technology. Although significant advancements have been witnessed in recent years for single-photon sources in the near-infrared band (λ ∼ 700–1000 nm), several challenges have yet to be addressed for ideal single-photon emission at the telecommunication band. In this study, we present a droplet-epitaxy strategy for O-band to C-band single-photon source-based semiconductor quantum dots (QDs) using metal-organic vapor-phase epitaxy (MOVPE). By investigating the growth conditions of the epitaxial process, we have successfully synthesized InAs/InP QDs with narrow emission lines spanning a broad spectral range of λ ∼ 1200–1600 nm. The morphological and optical properties of the samples were characterized using atomic force microscopy and micro-photoluminescence spectroscopy. The recorded single-photon purity of a plain QD structure reaches g⁽²⁾(0) = 0.16, with a radiative recombination lifetime as short as 1.5 ns. This work provides a crucial platform for future research on integrated microcavity enhancement techniques and coupled QDs with other quantum photonics in the telecom bands, offering significant prospects for quantum network applications.