Evolution Of Vacancy-Based Complexes In Synthetic Diamond Under Irradiation With High-Energy Electrons And Annealing

In this work, the formation of nitrogen-vacancy complexes (NV-centers) in a synthetic single crystal diamond as a result of irradiation with high-energy electrons and subsequent high-temperature annealing is studied. The evolution of the defect-impurity composition of an irradiated HPHT diamond single crystal upon vacuum annealing at temperatures from 800 to 1500 degrees C has been studied by optical spectroscopy (absorption and luminescence) in the visible spectrum. We used a method for estimating the concentration of NV-centers by the absorption spectra, which made it possible to estimate separately the concentrations of negatively charged and neutral NV-centers. The studies were carried out for two diamond growth sectors: {111} and {100}, which have different efficiencies of the impurity atoms incorporation during growth. It is shown that in the {100} growth sector the probability of the formation of neutral NV centers is 1.6 times higher than the probability of the formation of negatively charged centers due to the small amount of nitrogen donor impurity. To create quantum magnetic field sensors and gyroscopes, it is preferable to form NV centers in the {111} growth sector. The formation of H3 centers during high-temperature annealing was studied and it was shown that annealing should be performed at a temperature of 1000 degrees C or lower, otherwise nitrogen forms H3 centers rather than NV centers. It was shown that the optimal irradiation dose for HPHT diamond crystals is about 1018 cm(-2). In the {111} and {100} growth sectors, the Ramsey fringes measurement method was used to measure the coherence time T-2* = 0.88 mu s, which reaches the limit of 0.9 mu s due to the presence of C-13 carbon atoms with nuclear spin 1/2 in the diamond lattice.