Manipulation of the In Situ Nitrogen-Vacancy Doping Efficiency in CVD-Grown Diamond

Herein, the in situ generation of nitrogen-vacancy (NV) centers in diamond during chemical vapor deposition (CVD) is investigated depending on the electric-field strength at the sample position. The alteration of the electric-field strength is induced by changing the resonance conditions within the resonator cavity while keeping the growth input variables constant. The electric-field strength distribution is obtained by simulation results. During the growth experiments, optical-emission spectroscopy data is collected, which shows the impact of the electric-field strength on the radical concentrations within the plasma and the gas temperature. Through the reduction of the electric-field strength, the synthesis of thick, high-quality, nitrogen-doped diamond without the formation of a polycrystalline rim around the sample edges and the twinning-induced growth of polycrystalline grains was accomplished. Therefore, a reduced internal and more homogeneous stress distribution is achieved. Furthermore, significant influences on the in situ NV doping are discovered. In addition to a considerable gain of the in situ NV generation, also a major enhancement of the in situ incorporation efficiency of NV centers in comparison to N0s centers up to almost 3% is observed. Depending on the application, this makes posttreatment processes for additional NV generation dispensable.