Raman scattering by defect-induced excitations in boron-doped diamond single crystals

Polarized Raman spectra of the oriented boron-doped diamond with a different content of boron (≤200 ppm) were obtained with 514.5 and 1064 nm excitations. The additional bands were found in the region below 1200 cm−1. Their intensity increased with doping. It was shown that in polarized spectra these bands were in agreement with the singularities of density of phonon states (DOS) of diamond for the A1g, Eg and F2g symmetries. It was assumed that the ~900 cm−1 band which does not coincide with any DOS peak and has the highest resonance character may be attributed to the localized mode of boron in a diamond lattice. The spectra were accompanied by continuum that had the same symmetry F2g as optical phonon at 1333 cm−1.