13C NMR spectroscopy of amorphous hydrogenated carbon — further evidence of inhomogeneity

We report the 13C NMR spectra of amorphous hydrogenated carbon grown at various substrate temperatures and deconvolute these spectra into a contribution from hydrogen-bonded carbon and one from non-hydrogen bonded carbon. We interpret this deconvolution as evidence that this material is inhomogeneous and consists of hydrogen-rich and hydrogen-poor regions. As the substrate temperature is increased, the films have fewer hydrogen-rich regions, but the composition and structure of the hydrogen-rich regions do not change. Our results are in agreement with inhomogeneity model of Jager, Gottwald, Spiess and Newport.