Proceedings of the International scientific and practical conference ― Education and Scientific Progress‖ (February 13-15, 2026) / Publisher website: www.naukainfo.com. - Manchester, United Kingdom, 2026. - 206 p.

127 Keywords: CdTe thin films, optical properties, PRISA software, solar cell, renewable energy, computer simulation Introduction Studying the optical properties of thin CdTe films is important for assessing their suitability for use in photovoltaic heterostructures. Analysis of optical transmittance spectra over a wide wavelength range makes it possible to determine key material parameters such as the absorption coefficient, refractive index and its dispersion, the absorption edge, and the band gap energy [1, 2]. Therefore, obtaining reliable values of these parameters for thin films is essential for improving the efficiency of photovoltaic devices. Main text The investigated CdTe thin films were deposited on 0.17-mm-thick glass substrates by vacuum thermal evaporation. The film thickness was controlled by the deposition time (300 s). The source (evaporator) temperature was 800 K, and the substrate temperature during deposition was 475 K. After deposition, optical transmittance spectra were measured using an Agilent Technologies Cary Series UV– Vis–NIR spectrophotometer in the 500-2000 nm wavelength range. After measuring the optical transmittance spectrum, the optical properties of the films were determined using PRISA. As described in [3], PRISA (Fig. 1) enables the extraction of accurate values of the refractive index n, extinction coefficient k, film thickness d, and dispersion parameters E d , E 0 , n 0 , as well as the optical band gap E g , for homogeneous films deposited on a transparent, weakly dispersive substrate. The analyzed layer must exhibit at least three interference maxima in the transmittance spectrum. In the transparent region, the program applies the Swanepoel envelope method: it identifies interference maxima and minima, constructs the upper and lower envelopes T M and T m , and calculates n (λ), k (λ), and d . In the strong-absorption region, PRISA determines the absorption coefficient alpha and the optical band gap Eg from analysis of the Tauc plot.