In this study, we report for the first time that the addition of methane (CH4) flow rate in the p-type a-SiC: H layer greatly affects the electronic correlation in increasing the conversion efficiency of solar cells. The a-SiC: H p-type layer was grown using Plasma Enhanced Chemical Vapor Deposition (PECVD) on Indium Tin Oxide (ITO) substrate with various methane flow rates. The a-SiC: H p-type layer was characterized including the complex dielectric properties and the complex refractive index using Ellipsometric Spectroscopy (ES), while the surface roughness morphology was used Atomic Force Microscopy (AFM). In sample P-2 there is a change in the form of a decrease in the value of the refractive index < n > and the E0 energy in the lower energy compared to the P-1 sample with a change of 0.3 eV, an increase in the optical gap and a decrease in the value of the real and imaginary dielectric function. While the influence of an increase in the carbon composition of the amorphous network order shows the addition of amorphous tissue disorder. Our results, show that the optical magnitude of the p-type a-SiC: H layer is not only affected by the amount of carbon in the film but also the hydrogen which is thought to contribute.