Nitrogen in diamond thin films

Abstract

The local structure, dynamical properties and spin-lattice relaxation rate of nitrogen in diamond films produced by plasma-assisted chemical vapor deposition has been investigated by electron spin resonance in the temperature range 10–773 K. We find an isotropic g-value g = 2.0024 and hyperfine interaction constants A‖ = 40.7 G and A⊥ = 28.2 G consistent with an axial distortion along one of the four equivalent [111] directions. The peak to peak line width is ΔHpp = 3.0 G and the spin concentration is of the order of Ns = 9 × 1018 cm−3. The line shape has Lorentzian character in the center and Gaussian character in the wings. The high-temperature reorientation frequency was found to follow an Arrhenius-type behavior with ν0 = 3.2 × 1012 Hz and EJT = 0.69 eV. From the saturation behavior of the resonance line the spin-lattice relaxation time was found to be of the order to T1e ≈ 1.0 × 10−5 s at room temperature and T1e ≈ 1.0 × 10−3 s at 10 K.