High-pressure high-temperature industrial preparation of micron-sized diamond single crystals with silicon-vacancy colour centres

Negatively charged silicon-vacancy (SiV-) colour centres are considered to be promising room-temperature single-photon sources. The controlled preparation of high-grade industrial diamonds containing a certain amount of SiV- colour centres remains a significant technical challenge. Herein, micron-sized industrial-grade diamonds containing different concentrations of SiV- colour centres were prepared by adjusting the doping amount of Si powder under the pressure conditions of 5.0-5.2 GPa and temperatures of 1420-1500 degrees C. Al was used as the nitrogen getter in FeNiCo-C systems through the diamond film growth method (FGM). The results show that the intensity of the SiV- colour centres in synthesized diamond increases with increases in the Si doping amount. It has also been proved that nitrogen impurities inhibit the formation of SiV- colour centres in diamond. In addition, the diamond Raman peak positions exhibit a redshift (from 1330.88 cm(-1) to 1329.55 cm(-1)), and an increase in the Raman full width at half maximum (FWHM) (from 4.78 cm(-1) to 5.17 cm(-1)), indicating that Si enters the diamond lattice, but the diamond crystals still have a single sp(3) structure. Our research provides a fast, efficient and low-cost method for the controlled batch preparation of industrial-grade diamond containing SiV- colour centres.

Automated summary

This study successfully prepared industrial-grade diamonds containing different concentrations of SiV- color centers by adjusting the doping amount and pressure conditions. The results showed that increasing the Si doping amount enhanced the intensity of SiV- color centers in the diamond, while nitrogen impurities inhibited their formation.