The observation of defect-activated one-phonon infra-red absorption in diamond coat

Abstract

The one-phonon spectra of three specimens of diamond coat have been measured in the range 7 to 25 μ. Apart from minor features the spectra are similar to each other and to that of type I diamonds exhibiting a strong absorption band at 0.159 ev. The similarity between the coat and type I spectra indicates that nitrogen in concentrations of 2 to 3 × 10²⁰ atoms per cm³ is the major activating impurity in the coat. The comparatively small concentration of spin centres (S = ½) of 2 × 10¹⁹cm⁻³ suggests that most of this nitrogen is in aggregated form.