Fig. 2: Simulated photoluminescence spectrum.

a Calculated PL spectrum of \({{{{{\rm{C}}}}}_{{{{\rm{i}}}}}{{{{\rm{O}}}}}_{{{{\rm{i}}}}}}^{0}\) defect, showing Huang-Rhys factor of S = 2.1. b Calculated PL sideband relative to the ZPL energy and the Si partial Huang–Rhys factors. Our results are compared to the experimental PL sideband reported by Ishikawa et al.31.