Amorphous nonstoichiometric Ge1-x-Cx:H compounds obtained by radiolysis-chemical vapor deposition of germane/ethyne or germane/allene systems:: A bonding and microstructure investigation performed by x-ray photoelectron spectroscopy and Raman spectroscopy

Hydrogenated germanium carbides have been produced by x-ray activated-chemical vapor deposition from germane/ethyne or germane/allene systems. The chemical composition and structure of the reaction products as a function of the hydrocarbon percentage in the irradiated mixture and of the solid annealing temperature have been studied and discussed. Bonding and microstructure of these alloys have been investigated by x-ray photoelectron spectroscopy and Raman spectroscopy. The results indicate that the solids are formed by a randomly bound network of carbon, germanium and hydrogen atoms with composition, and characteristics and properties variable with the radiolysis experimental conditions. The spectra show the presence of Ge-C bonds and a partial polymerlike character of the films with hydrogen atoms bonded both to germanium and carbon. Clustered-germanium zones dispersed in the material matrix are also evidenced. The results suggest that the conductive properties of the materials are related to the density of these amorphous clusters. The annealing causes compositional and structural transformations becoming more drastic with temperature. (c) 2007 American Institute of Physics.