The evaluation of some disorder parameters of RF glow discharge hydrogenated amorphous carbon films a-C:H

Abstract
The fundamental optical absorption edge of RF glow discharge hydrogenated amorphous carbon films a-C:H is studied by direct optical transmission spectroscopy. It is observed that the optical energy gap EG decreases and an Urbach slope parameter epsilon 0 increases when the substrate temperature Ts increases. These results are correlated with ESR data and data on the density of states at the Fermi level N(EF) obtained from DC conductivity measurements. As one of the possible explanations of the above effects, the effective medium approximation model (EMA) was used.