The demonstration of single-photon emission in the near-infrared range in silicon offers an enticing perspective for developing industrial-scale silicon-based single-photon sources that emit at telecom wavelengths. Among the recently identified Si-based quantum emitters, the G center is a carbon-related point defect in silicon with an emission spectrum characterized by a zero-phonon line (ZPL) emission at 1279 nm, and with appealing features for the implementation of quantum technologies, including defect coupling with nuclear and electron spin degrees of freedom.

Theoretical studies have shown that the configuration of this complex represents a structurally metastable state [1], thereby raising the need to optimize the post-implantation thermal treatment, which is currently one of the main factors limiting the scalable manufacturing of color centers in silicon.

In this contribution, we report the activities based on two primary directives. The first one aims to understand the role of radiation damage during the ion implantation process, which is used to introduce extrinsic impurities into the silicon lattice. The emission properties of intrinsic self-interstitial W centers in high-purity and C-rich silicon substrates, following keV implantation, are investigated using single-photon-sensitive cryogenic confocal microscopy. This technique enables the identification of the effects of post-implantation thermal treatment on the formation of telecom quantum emitters.

The second experimental approach aims to explore more responsive thermal processing and implantation protocols to achieve higher creation yields. Here, we present the direct and non-destructive localized activation of G centers upon spatially resolved ns-pulsed laser annealing in keV carbon-implanted high-purity silicon substrates. Specifically, this approach involves ns heat transients during the annealing step, offering a practical off-equilibrium pathway for competitive processes in forming defective complexes and radically different possibilities for defect engineering [2].

[1] Deák, P., et al., Nat. Commun. 14, 1–6 (2023)

[2] Andrini, G. et al., Commun. Mater., 5, 47, (2024)