Suppression and elimination of [NV] and [SiV] defects in CVD single crystal diamond

Investigating the photoluminescence spectroscopy (PL) of CVD diamond with 10 ppm N₂ added in the reaction gas, it demonstrates that [NV]⁰ and [NV]^- related to N impurity and [SiV] related to Si impurity are the main defects in diamond. After high temperature and high pressure (HPHT) treatment, the [NV]⁰ peak intensity was weakened, the [NV]^- peak intensity was enhanced, the [SiV] peak intensity was significantly enhanced, and [SiV]^- broad peak appears when the N₂ content was decreased to 1 ppm and 0.5% O₂ was added in the reaction gas, the [NV]⁰ and [NV]^- peaks disappeared. When the O₂ was increased to 1%, the [SiV] peak intensity significantly decreased. As the O₂ content continued to increase, the decreasing of [SiV] peak intensity slowed down. These results demonstrated that a small amount of O₂ addition was helpful to the inhibition and elimination of N and Si impurities in CVD diamond.