Highly intensive emission of the NV? centers in synthetic HPHT microdiamonds at low nitrogen doping

摘要

Synthetic high-pressure high-temperature (HPHT) microdiamonds demonstrate strong resonant-like enhancement of the NV? photoluminescence (PL) at unexpectedly low concentration of the substitutional nitrogen atoms (NS) of 90 ppm, which is significantly smaller than the ～250 ppm characteristic for conventional HPHT synthesis. The EPR, Raman, and luminescent spectroscopies, including time-resolved PL, provide evidence that this is due to competition between the increase in PL with increasing concentration of the NV? centers and nonradiative deactivation of these centers by defects induced by the NS in the diamond crystal lattice. It is suggested that the intensity of the NV? center emission can be optimized by the appropriate choice of nitrogen doping concentration which does not substantially disrupt the diamond crystal lattice.