Paramagnetic defects in diamond films synthesized by the hot filament chemical vapour deposition

Abstract

Defects in nitrogen-doped diamond films, produced by hot filament chemical vapour deposition have been studied by Electron Spin Resonance (ESR), Raman spectroscopy and Scanning Electron Microscopy (SEM). The peak-to-peak ESR line width (ΔHpp) varies in the range 0.36-0.52 mT and depends on the nitrogen concentration in the process gas. In the case of nitrogen-doped diamond films ESR spectrum shows a hyperfine structure typical of NS0 paramagnetic centre. The shape of the central ESR line shows that it is a superposition of two components: a narrower Lorentzian and a broader Gaussian one, characterized by different saturation behaviour. With increasing nitrogen concentration in process gas the ratio of integral intensities AG/AL (Gausian to Lorentzian) of ESR spectrum also increases. The Raman spectra show that with increasing doping level the diamond Raman line at 1332.5 cm-1 broadens, the broad band at about 1530 cm-1 becomes more pronounced what indicate on degradation of diamond crystallinity and it is in agreement with SEM observation. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)