Monoisotopic Ensembles of Silicon-Vacancy Color Centers with Narrow-Line Luminescence in Homoepitaxial Diamond Layers Grown in H2–CH4–[x]SiH4 Gas Mixtures (x = 28, 29, 30)

Silicon-vacancy (SiV–) color center in diamond is of high interest for applications in nanophotonics and quantum information technologies, as a single photon emitter with excellent spectral properties. To obtain spectrally identical SiV– emitters, we doped homoepitaxial diamond films in situ with 28Si, 29Si, and 30Si isotopes using isotopically enriched (>99.9%) silane SiH4 gas added in H2–CH4 mixtures in the course of the microwave plasma-assisted chemical vapor deposition process. Zero-phonon line components as narrow as ∼4.8 GHz were measured in both absorption and luminescence spectra for the monoisotopic SiV– ensembles with a concentration of a few parts per billion. We determined with high accuracy the Si isotopic energy shift of SiV– zero-phonon line. The SiV– emission intensity is shown to be easily controlled by the doped epifilm thickness. Also, we identified and characterized the localized single photon SiV– sources. The developed doping process opens a way to produce the SiV– emitter ensembles...