Structure and bonding of hydrocarbon plasma generated carbon films: An electron energy loss study

Electron energy loss spectroscopy has been used to study the structure and the bonding in hard amorphous carbon films (aC:H) prepared by plasma decomposition of benzene. EXAFS spectra indicate an amorphous and not a microcrystalline structure for aC:H films. The near-edge structure of the carbon K-amsorption edge reveals a considerable amount of π bonding in the aC:H films. The optical constants were derived by a Kramers-Kronig analysis of the loss functions for energies less than 40 eV. From the sum rule for ε₂, we derive that $\text{1}\text{3}$ of the carbon atoms are trigonally bonded and 273 of the carbon atoms are tetrahedrally bonded.