On the Formation of Dense Arrays of Nitrogen–Vacancy Centers in Synthetic Single-Crystal Diamonds for Quantum Sensors

The dynamics of the formation of ensembles of nitrogen–vacancy color centers (NV centers) in single-crystal diamond plates after irradiation by high-energy (2 MeV) electrons and subsequent annealing is investigated. The concentration of the nitrogen impurity is determined from the infrared (IR) absorption spectrum to be 90 and 4 ppm for the diamond growth sectors {111} and {001}, respectively. The transverse relaxation times $$T_{2}^{*}$$ for the electron spin of NV centers are studied; they are found to amount to 200 and 900 ns for the {111} and {001} sectors, respectively, and are limited by the concentration of paramagnetic impurity defects in diamond. The sensitivity of quantum sensors based on the obtained ensembles of NV centers is estimated; the estimation shows feasibility of using denser ensembles in low-field magnetometry.