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

Abstract

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 °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 sp3 structure. Our research provides a fast, efficient and low-cost method for the controlled batch preparation of industrial-grade diamond containing SiV− colour centres.