Hydrogen-related IR absorption in chemical vapour deposited diamond

Polycrystalline and homoepitaxial diamond films deposited from high12C and high13C-containing gases have been characterized by Fourier transform IR spectroscopy. We present evidence that some spectral structures in the well-known C-H stretch band around 2850cmhighminus1 omnipresent in polycrystalline films are related to the incorporation of nitrogen, In homoepitaxial diamond films, the isotopic replacement of carbon, hydrogen and nitrogen by high13C, high2H and high15N reveals that a CH centre without nitrogen participation is responsible for a new vibrational absorption band observed at 3123cmhighminus1 in the spectral vicinity of the previosly observed 3107cmhighminus1 absorption band in natural diamond. The bond centred position can be excluded for this vibrational transition. In addition, new hydrigen-related elecronic transitions have been observed in the near-IR around 7300cmhighminus1.