In this study, hydrogenated amorphous silicon carbon (a-Si1-xCx: H) thin films were synthesized on Si substrates by plasma enhanced chemical vapor deposition (PECVD) technique. The source gases used were C2H4, SiH4, and H-2 (for dilution). The compositional parameter x is found to be closely relevant to practical vibrational and optical properties of this material. XPS and FTIR spectra strongly support the existence of C-Si covalent bonds in the grown thin films. Raman spectra do not show a strong Si-C Raman peak. The Photoluminescence result is quite different from the previous reports.