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We report the detection of individual emitters in silicon belonging to seven different families of optically active point defects. These fluorescent centers are created by carbon implantation of a commercial siliconon-insulator wafer usually employed for integrated photonics. Single photon emission is demonstrated over the 1.1-1.55 μm range, spanning the O and C telecom bands. We analyze their photoluminescence spectra, dipolar emissions, and optical relaxation dynamics at 10 K. For a specific family, we show a constant emission intensity at saturation from 10 K to temperatures well above the 77 K liquid nitrogen temperature. Given the advanced control over nanofabrication and integration in silicon, these individual artificial atoms are promising systems to investigate for Si-based quantum technologies.

Spin defects in hexagonal boron nitride (hBN) are promising quantum systems for the design of flexible two-dimensional quantum sensing platforms. Here we rely on hBN crystals isotopically enriched with either 10B or 11B to investigate the isotope-dependent properties of a spin defect featuring a broadband photoluminescence signal in the near infrared. By analyzing the hyperfine structure of the spin defect while changing the boron isotope, we first confirm that it corresponds to the negatively charged boron-vacancy center ($${{{{{{{{\rm{V}}}}}}}}}_{{{{{{{{\rm{B}}}}}}}}}^{-}$$ V B − ). We then show that its spin coherence properties are slightly improved in 10B-enriched samples. This is supported by numerical simulations employing cluster correlation expansion methods, which reveal the importance of the hyperfine Fermi contact term for calculating the coherence time of point defects in hBN. Using cross-relaxation spectroscopy, we finally identify dark electron spin impurities as an additional source of decoherence. This work provides new insights into the properties of $${{{{{{{{\rm{V}}}}}}}}}_{{{{{{{{\rm{B}}}}}}}}}^{-}$$ V B − spin defects, which are valuable for the future development of hBN-based quantum sensing foils.

Controlling the quantum properties of individual fluorescent defects in silicon is a key challenge toward large-scale advanced quantum photonic devices. Research efforts have so far focused on extrinsic defects based on impurities incorporated inside the silicon lattice. Here, we demonstrate the detection of single intrinsic defects in silicon, which are linked to a tri-interstitial complex called the W-center, with a zero-phonon line at 1.218 μm. Investigating their single-photon emission properties reveals new information about this common radiation damage center, such as its dipolar orientation and its photophysics. We also identify its microscopic structure and show that, although this defect does not feature electronic states in the bandgap, Coulomb interactions lead to excitonic radiative recombination below the silicon bandgap. These results could set the stage for numerous quantum perspectives based on intrinsic luminescent defects in silicon, such as integrated quantum photonics and quantum communications.

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We report the fabrication of isolated G centers in silicon with single photon emission at optical telecommunication wavelengths. Our sample is made from a silicon-on-insulator wafer, which is locally implanted with carbon ions and protons at various fluences. Decreasing the implantation fluences enables us to gradually switch from large ensembles to isolated single defects, reaching areal densities of G centers down to ∼0.2  μm−2. Single defect creation is demonstrated by photon antibunching in intensity-correlation experiments, thus establishing our approach as an effective procedure for generating single artificial atoms in silicon for future quantum technologies.