HYDROGEN-RELATED IR ABSORPTION IN CHEMICAL-VAPOR-DEPOSITED DIAMOND

Polycrystalline and homoepitaxial diamond films deposited from C-12- a nd C-13-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 2850 cm(-1) omnipresent in poly crystalline films are related to the incorporation of nitrogen. In hom oepitaxial diamond films, the isotopic replacement of carbon, hydrogen and nitrogen by C-13, H-2 and N-15 reveals that a CH centre without n itrogen participation is responsible for a new vibrational absorption band observed at 3123 cm(-1) in the spectral vicinity of the previousl y observed 3107 cm(-1) absorption band in natural diamond. The bond ce ntred position can be excluded for this vibrational transition. In add ition, new hydrogen-related electronic transitions have been observed in the near-IR around 7380 cm(-1).