Strain-Engineered Deterministic Quantum Dots for Telecom O-Band Emission Using Buried Stressors

The deterministic realization of quantum light sources operating at telecom wavelengths is essential for long-distance fiber-based quantum communication and distributed quantum computing. In this work, we demonstrate that telecom O-band emission can be achieved from site-controlled InGaAs/GaAs quantum dots (QDs). Our concept utilizes a buried AlAs/AlOx stressor layer with the unique feature of inducing a well-defined and controllable tensile strain field at the growth surface, enabling both site-selective nucleation at the mesa’s centers and a redshift of QD emission to the ∼1.3 μm wavelength range. This concept not only eliminates the need for strain-reducing layers (SRLs), which are known to degrade optical coherence, but also provides spatial control and spectral tunability. The grown telecom QDs show single-photon emission with g(2)(0) = (5.0 ± 1.0) × 10–2 at 4 K and (2.8 ± 0.3) × 10–1 at 77 K, demonstrating the quantum nature and thermal stability of the emitters. The emission characteristics of complex excitonic states are analyzed using 8-band k·p and configuration-interaction modeling, which quantitatively reproduces the experimental observations. Finally, we present a theory-supported strategy to further redshift the emission toward the center of the O-band and beyond by employing a multiburied stressor approach. This combined framework of experiment and theory establishes the buried stressor concept as a scalable route toward highly coherent, position-controlled O-band quantum emitters compatible with scalable photonic integration.