Formation mechanism and regulation of silicon vacancy centers in polycrystalline diamond films

Diamond silicon vacancy centers(Si-V centers) have important application prospects in quantum information technology and biomarkers. In this paper, the formation mechanism and regulation method of Si-V center during the growth of polycrystalline diamond on silicon substrate were studied. By changing the ratio of nitrogen and oxygen in the growing atmosphere of diamond, the photoluminescence intensity of Si-V center can be controlled effectively, and polycrystalline diamond samples with the ratio of Si-V center photoluminescence peak to diamond intrinsic peak as high as 334.46 and as low as 1.48 were prepared. It was found that nitrogen promoted the formation of Si-V center during the growth process，and oxygen inhibited.The surface morphology and photoluminescence spectra of the samples show that the photoluminescence peak intensity of Si-V center is positively correlated with the grain size of diamond, and the Si-V centers photoluminescence peak in the diamond film with obvious preferred orientation of crystal plane is higher. The distribution of Si and Si-V centers on the surface of polycrystalline diamond was further characterized and analyzed by photoluminescence, Raman surface scanning and depth scanning spectroscopy. It was found that during the growth of polycrystalline diamond, the substrate Silicon diffused into the diamond grain first and then into the crystal structure to form the Si-V center. This paper provides a theoretical basis for the development and application of Si-V centers in diamond.