Specific features of 325 nm Raman excitation of heavily boron doped polycrystalline diamond films

A set of MPCVD films was prepared from 0.5% CH4/H2 and B2H6 with B/C in the gas phase from 0 to 8000 ppm. When the excitation wavelength of their Raman spectra is switched from 632.8 to 325 nm: The Fano induced dip switches from high to low wave number side of the “1332 cm− 1” signal. The deformation and the downward shift of this signal decrease. The G band, diamond second order, CHx bands appear. The evolution of these bands with increasing B / C is reported and discussed.