Electron spin contrast of high-density and perfectly aligned nitrogen-vacancy centers synthesized by chemical vapor deposition

Nitrogen-vacancy (NV) centers in diamonds provide a high-sensitivity magnetometer. We investigated the spin properties of high-density and perfectly aligned NV centers grown using the chemical vapor deposition method by varying the nitrogen concentration. Basically, the optical initialization and spin-dependent fluorescence are determined by intersystem crossing (ISC) in the excited state. In this study, we found that nitrogen impurities lead to a non-radiative and spin-mixing decay working as a competitive pathway against the ISC, using time-resolved fluorescence analysis. Our results will elucidate NV-defect interaction, which significantly contributes to the quality of the quantum material. (author)