THE EFFECT OF NITROGEN IMPURITY ON PARAMETERS OF THE FUNDAMENTAL RAMAN BAND OF DIAMOND MONOCRYSTALS

Abstract

The effect of nitrogen defects in monocrystals of natural and synthesized diamond on the position and width of the fundamental Raman band has been investigated. The samples containing main types of the nitrogen defects in diamond lattice at the impurity content of 1-1500 ppm have been taken for the study. Based on the analysis of parameters of the Stokes and anti-Stokes components in Raman spectra of the crystals that are placed in a cell with distilled water to minimize the influence of heating by exciting laser radiation, the effect of the nitrogen impurity presence in the crystalline lattice of diamond has been exhibited. It is shown that an increase of the nitrogen impurity content in the crystals within the studied concentration range results in the Raman band broadening from 1.61 to 2.85 cm^{- 1} and the maximum shifting to the low-frequency region from 1332.65 to 1332.3 cm^{- 1} . The observed effect value is directly proportional to the concentration of impurity atoms and depends on the form of the impurity ingress into the diamond lattice. It has been found that the change in the position and half-width of the fundamental Raman band for diamond is consistent with the magnitude of the distortions of the crystalline lattice parameter due to the presence of impurity defects and obeys the Gruneisen law.