Advanced Physical Research

In this study, the optical properties of CdSe and CdS thin films synthesized on glass substrates were systematically investigated using the Spectroscopic Ellipsometry (SE) method. The samples were measured at room temperature using an M-2000 rotating compensator Spectroscopic Ellipsometer within the photon energy range of 1.5-7 eV. Based on appropriate dispersion models, the spectral dispersion of optical constants was obtained, and the film thickness, real and imaginary parts of the dielectric function, as well as the refractive index and extinction coefficient, were determined with high accuracy. The analysis showed that both CdSe and CdS thin films exhibit high transparency depending on thickness and possess favorable optical properties for use in solar cells. Furthermore, the band gap energy was found to be approximately 1.7 eV for CdSe and about 2.4 eV for CdS. These results indicate that CdS, with its wider band gap, is more suitable as a transparent window layer, while CdSe, with a narrower band gap, is better suited as an absorber layer. Thus, Spectroscopic Ellipsometry proves to be a powerful and effective research method for the comparative analysis and optimization of photovoltaic materials.