EPR of NEW phosphorus-containing CENTERS in synthetic diamonds
a:2:{s:4:"TEXT";s:121:"V. A. Nadolinnyi1, A. Yu. Komarovskikh1, Yu. N. Pal’yanov2, I. N. Kupriyanov2";s:4:"TYPE";s:4:"html";}
1A. V. Nikolaev Institute of Inorganic Chemistry, Siberian Division, Russian Academy of Sciences
2V. S. Sobolev Institute of Geology and Mineralogy, Siberian Division, Russian Academy of Sciences
Keywords: phosphorus, nitrogen, vacancy, synthetic diamond, BARS technology, electron paramagnetic resonance
Subsection: EPR SPECTROSCOPY
Abstract
The effect is studied of electron and X-ray irradiation on phosphorous centers in synthetic diamonds grown in the P–C medium by the Bars technology. After exposure to X-ray irradiation, a new paramagnetic phosphorus-containing center NP6, in addition to the phosphorous centers NP4 and NP5, is observed in diamonds annealed at a temperature of 2300°С and pressure of 7.5 GPa. The spectrum of NP6 is simulated to give the following parameters: A1 = 29.42 G, A2 = 23.28 G, A3 = 75.85 G, g1 = 2.00085, g2 = 2.00083, and g3 = 2.00083. The NP4–NP6 centers are assumed to be genetically related to the three nitrogen–phosphorous centers NP1–NP3 and be formed as a result of the transformation of the tetrahedral environment around the phosphorous atom into an octahedral environment at an annealing temperature of 2300°C. The synthetic diamonds annealed at 2300°С were successively exposed to irradiation with electrons with energies of 3.5 MeV (5×1017 e/cm2) and annealing at temperatures of 500°C and 700°С. The EPR method is used to find that annealing of the electron-irradiated crystals at 700°С leads to the formation of a new paramagnetic center with spin S = 1 and hyperfine structure (HFS) from one phosphorus atom with the parameters: g = 2.0012, D = 19.7 G, and А(Р) = 3.6 G. The center is likely to have an eight-vacancy chain structure with a phosphorus atom located at the center.
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