In this paper, a ZnO/CdS/CuO:Co solar cell was prepared on a glass/ITO substrate. First we use RF sputtering to deposit the window (ZnO) layer by optimizing the oxygen pressure while keeping the RF power at 200 W. Fourier transform infrared and X-Ray reflectometry spectra were carried out and it is found that 30% of O2 is the optimal percentage to obtain the best density and the best refractive index for the ZnO layer. The CdS layer was then deposited by the sol-gel method to align the energy bands and a layer of CuO:Co with a thickness of 750 nm was deposited, also by reactive RF-sputtering technique. Finally, the electrical contacts were made by depositing circular silver electrodes. The obtained photovoltaic activity of device confirms that the aforementioned method is promising for further future optimizations.