Electron paramagnetic resonance studies were made of thin films that had been prepared by means of hot-filament chemical vapor deposition, using methane concentrations of 0.25 to 5%. It was found that the bulk spin concentration and the peak-to-peak line-width of the characteristic g = 2.0027 electron paramagnetic resonance spectrum increased in samples that had been grown using the higher methane concentration. It was shown that the spectrum contained components that were due to paramagnetic defects which were related to non diamond-like C phases.

D.J.Keeble, B.Ramakrishnan: Applied Physics Letters, 1996, 69[25], 3836-8