Photoluminescence studies of nitrogen-vacancy and silicon-vacancy centers transformation in CVD diamond.

In this study, the low-temperature micro-photoluminescence (PL) technology was employed to investigate the transformation of nitrogen-vacancy (NV), silicon-vacancy (SiV) centers in diamond crystal. Results showed that the NV and SiV luminescence were controlled by electron irradiation followed by thermal annealing. Both centers vanished together with the emergence of neutral single vacancy (GR1 center) after 200 keV electron irradiation. Interstitial related defects and vacancies were activated to diffuse by annealing (above ∼400 and 700 °C, respectively). The vacancies migrated to be captured by N and Si atoms due to the strain fields around the atoms attracted vacancies, and the NV and SiV centers appeared again in the PL spectra. In addition, compared the annealing behavior with NV center, the new emission at 639.7 nm was attributed to the nitrogen combined with carbon interstitials.