Boltzmann Model of NV Color Center Concentration and Annealing Temperature

Nitrogen-Vacancy (NV) centers of diamond has excellent optical properties such as zero phonon line (ZPL) observed at room temperature, stable luminescence, long coherence time, etc. The concentration of NV centers is one of the important factors affecting its performance and application. In this study, the fluorescence spectra of diamond NV centers at different annealing temperatures were analyzed. The relationship between NV center concentration and annealing temperature at two different electron injection doses was studied. First, diamond samples containing different concentrations of NV centers were prepared by electron irradiation and high temperature annealing. Then, the fluorescence spectra of NV centers under different preparation conditions were measured and analyzed, and the total fluorescence intensity of the phonon bands was obtained to characterize the NV center concentration. The relationship between NV center concentration and annealing temperature was analyzed. According to the variation of NV center concentration in different temperature ranges, three zones of suppression zone, diffusion zone and saturation zone were proposed. The Boltzmann model of NV center concentration and annealing temperature was obtained according to the experimental data, and the rate of change of NV center concentration near 780 °C is the fastest.