With the increasing consumption of conventional energy and the gradually serious environmental crisis, the research and application of solar cells attracted a worldwide attention. In the past ten years, the progress of the thin film preparation technology promoted the technology of the second generation Solar cells based on semiconductor thin film materials. Due to the demand for less material, the thin film solar cell technology can effectively reduce the cost of materials. Moreover, the thin film materials can flexibly deposit on substrates such as glass, stainless steel, and plastic, especially suitable for solar building integration. Thin film solar cells (TFSC) are a promising approach for terrestrial and space. For large-area devices required for realistic applications, thin-film device fabrication becomes complex and requires proper control over the entire process sequence. Proper understanding of thin-film deposition processes can help in achieving high-efficiency devices over large areas. The study is motivated by the broader need for scalable and cost-effective semiconductor coatings for energy conversion, for which chemical-bathderived CdS remains a technologically relevant benchmark till now. Thin films deposited on glass substrates are generally characterized using X-ray diffraction, scanning electron microscopy, compositional analysis, and UV & Visible light spectroscopy to evaluate phase constitution, crystallinity, surface coverage, stoichiometry, transmittance, and optical band-gap behaviour.