Structural and electronic properties of Si nanocrystals embedded in amorphous SiC matrix

Si-rich hydrogenated amorphous silicon carbide thin films were prepared by plasma-enhanced chemical vapor deposition technique. As-deposited films were subsequently annealed at 900 degrees C and 1000 degrees C to form Si nanocrystals embedded in amorphous SiC matrix. Raman spectra demonstrate the formation of Si nanocrystals with size around 7-9 nm. For the sample annealed at 1000 degrees C, the crystallinity can be reached to 70%. As increasing the annealing temperature, the dark conductivity is increased accompanying with the increase of crystallinity of the film. The dark conductivity reaches to 1.2 x 10(-6) Scm(-1) for the sample annealed at 1000 degrees C, which is 4 orders of magnitude higher than that of as-deposited film. It is found that the carrier transport process is dominated by the thermally activated transport process according to the temperature-dependent conductivity results. (C) 2011 Elsevier B. V. All rights reserved.