METHOD FOR PRODUCING NITROGEN-FREE DIAMOND CRYSTALS Russian patent published in 2022 - IPC B01J3/06 C30B29/04 C01B32/26 

FIELD: technological processes.

SUBSTANCE: invention relates to production of nitrogen-free diamond crystals containing optically active centers SiV, GeV and SnV, for use in photonic and optoelectronic devices. Method of producing nitrogen-free diamond crystals involves exposing the carbon-rare-earth element system to high pressure and temperature in the region of thermodynamic stability of diamond using rare-earth metals as catalysts, which are one of rare-earth metals La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y, wherein one or more alloying elements of group IV, such as Si, in form of an impurity in graphite in amount of about 120 ppm and/or Ge or Sn in amount of 5–10 wt.% of the amount of the rare-earth element, which form optically active centers in the diamond at pressure of not less than 7.8 GPa and temperature of 2,000–2,100 °C for at least 1 hour.

EFFECT: obtaining colorless diamonds in the form of monocrystals in the form of octahedrons, cuboctahedrons and complex polyhedral polyhedrons with size from 100 mcm to 2 mm.

1 cl, 3 dwg, 1 tbl, 5 ex