Effect of growth rate on the incorporation of silicon impurity in single crystal diamond

In this paper, we systematically investigate the influence of growth rate on the incorporation of silicon in single crystal diamond. The intensity of SiV− center is significantly enhanced with the increase of methane flow rate. By analyzing the optical emission spectrum and photoluminescence spectrum of samples grown with different methane concentrations, the enhancement of SiV− intensity is not associated with the Si–C concentration in the precursor but with the higher growth rate. In addition, an increased oxygen flow rate significantly decreases the intensity of SiV− center, which is attributed to the formation of insoluble silicon oxide as well as the relatively lower growth rate. Finally, we propose a growth model to explain the effect of growth rate on the incorporation of silicon impurity.