Local Droplet Etching‐Assisted Quantum Dot Epitaxy for Telecom C‐Band Quantum Light Emitters

Abstract

ABSTRACT Significant progress in quantum light sources for quantum communication applications requires reproducible and symmetric quantum emitters acting as single‐photon sources capable of generating entangled photons on demand at specific telecom wavelengths. Here, we propose telecom‐emitting epitaxial quantum dots (QDs) fabricated by metal‐organic vapor phase epitaxy (MOVPE) using the local droplet etching (LDE) approach. The resulting well‐defined, low‐density (/) QDs based on are formed in symmetric LDE nanoholes in . Detailed transmission electron microscopy provides comprehensive insight into the structural properties of the QDs. Photoluminescence spectroscopy reveals single QD emission lines (linewidth  meV, fine structure splitting  μeV) with negligible impact of nonradiative processes, with decay  ns comparable to theoretical simulations, whereas second‐order autocorrelation measurements confirm clear single‐photon emission with under above‐band continuous‐wave excitation and under pulsed excitation. Precise numerical modeling, combining multiband and configuration interaction methods, identifies thermal excitation pathways that explain the persistence of emission up to liquid‐nitrogen temperatures. These results highlight the versatility of the LDE approach for integrating new material systems and provide a promising foundation for future studies aimed at scalable fabrication of quantum light sources with tailored emission properties.