The aim of the present paper is the study of the RF power effects on the properties of hydrogenated amorphous silicon-carbon (a-SiC:H) films, deposited in high power regime in a conventional plasma enhanced chemical vapor deposition system by using silane-methane gas mixtures highly diluted in hydrogen. Varying the RF power chemically ordered a-SiC:H alloys can be grown controlling the carbon content, C/[C+Si], and consequently the energy gap from 0.20 to 0.57 and 2.17 to 3.23 eV, respectively. C-rich films show defect density lower than 2 X 10(17) cm(-3) and photoluminescence (PL) at room temperature. The PL peak position of the spectra shifts from 1.70 to 2.54 eV as the carbon content increases from 0.3 to 0.57.