Mid-infrared spectroscopy of sulphur and selenium donors in silicon for quantum optics

We have manufactured mid-infrared chalcogen donor centres in silicon by high-temperature diffusion doping. Electrical characterisation has shown that we can control the ratio of different donor centre concentrations. FT-IR spectroscopy reveals very narrow lines in the mid-infrared spectral band. We have now performed the first time-domain measurements on the donor centre excited states. Our preliminary results suggest excited state lifetimes with nanosecond timescales.