Infrared optical properties of heavily B-doped nanocrystalline diamond films on low alkaline glass substrates

Abstract

We measured the optical reflectance and transmittance spectra of the heavily B-doped nanocrystalline diamond thin films deposited on low alkali barium alumino-borosilicate glasses in a broad spectral range from ultraviolet to infrared light. We succeed to calculate separately the dielectric functions of the semitransparent B-doped nanodiamond film and the glass substrate. The infrared dielectric function of a glass substrate is approximated by the classical Lorentz sum model of bounded oscillators whereas the infrared dielectric function of the heavily B-doped nanodiamond film by the Drude model of free carriers. The free carrier concentration calculated from the plasma frequency only roughly corresponds to the free carrier concentration measured in Hall effect. Moreover, from the Drude model follows the high damping of free carrier oscillations in B-NCD that correlates to their low Hall mobility.