No abstract

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 with energy confined in an extremely narrow range.

The sensitivity of magnetic and electric field sensors based on nitrogen-vacancy (NV) center in diamond strongly depends on the available concentration of NV and their coherence properties. Achieving high coherence times simultaneously with high concentration is a challenging experimental task. Here, we demonstrate that by using a temperature gradient method of high-pressure, high-temperature growing technique, one can achieve nearly maximally possible dephasing T 2 * times, limited only by carbon nuclear spins at low nitrogen concentrations or nitrogen electron spin at high nitrogen concentrations. Hahn-echo T 2 coherence times were also investigated and found to demonstrate reasonable values. Thus, the high-pressure, high-temperature technique is a strong contender to the popular chemical vapor deposition method in the development of high-sensitivity, diamond-based sensors.