Crystallization and characteristics of {100}-oriented diamond with CH₄N₂S additive under high pressure and high temperature

Diamond crystallization was carried out with CH₄N₂S additive in the FeNiCo-C system at pressure 6.0 GPa and temperature ranging from 1290 °C to 1300 °C. The crystallization qualities of the synthetic crystals were characterized by Raman spectra and the Raman peaks located at 1331 cm⁻¹. Fourier transform infrared (FTIR) results showed that the hydrogen-related absorption peak of the as-grown diamond was at 2920 cm⁻¹, respectively. Interestingly, A-center nitrogen was observed in the obtained diamond and the characteristic absorption peaks located at 1095 cm⁻¹ and 1282 cm⁻¹. Especially, the absorption peak at 1426 cm⁻¹ attributing to the aggregation B-center nitrogen defect was distinctly found when the CH₄N₂S content reached 0.3 mg in the synthesis system, which was extremely rare in synthetic diamond. Furthermore, optical color centers in the synthesized crystals were investigated by photoluminescence (PL). (paper)