Bright Single-Photon Source in a Silicon Chip by Nanoscale Positioning of a Color Center in a Microcavity

We present an all-silicon source of near-infrared linearly-polarized single photons, fabricated by nanoscale positioning of a color center in a silicon-on-insulator microcavity. The color center consists of a single W center, created at a well-defined position by Si+ ion implantation through a 150 nm-diameter nanohole in a PMMA resin mask. A circular Bragg grating cavity resonant with the W's zero-phonon line (ZPL) at 1217 nm is fabricated at the same location as the nanohole.
High-purity photon antibunching is observed for the cavity-coupled W center under above-gap continuous-wave excitation (g⁽²⁾(0) = 0.03 ± 0.01), with a photoluminescence intensity exceeding 10⁶ counts per second and 99% ZPL fraction. We demonstrate the triggered emission of single photons with 93% purity under weak pulsed laser excitation, and reveal a detrimental effect of re-pumping processes under strong excitation.
Further improvement is expected by mitigating the re-pumping issue, which is common for solid-state quantum emitters under above-gap excitation. This work marks a significant advance for the deterministic fabrication of on-demand sources of indistinguishable single photons in silicon photonics.