The effect of carbon on the density of states of hydrogenated amorphous silicon-carbon alloy films prepared from silane and propane

The compositional dependence of the density of states near the Fermi level of hydrogenated amorphous silicon-carbon alloys from silane-propane mixtures was examined. Optical and electrical measurements reveal two distinct regions of behaviour: a low propane concentration regime and a high propane concentration regime. We propose that at low propane concentration there is only a small carbon contribution to the formation of the silicon-based lattice and at high propane concentration a new structure is formed. © 1989.