In [6] this fact is explained by film porosity; and in [2, 5] high sensitivity of film optical properties to composition deviation from stoichiometry is registered in the film near-surface layer. Schematic presentation of CdTe/CdS solar cell in “superstrate” configuration showing different layers. It is mainly used as the semiconducting material in cadmium telluride photovoltaics and an infrared optical window. The arrangement of p-type and n-type regions being in different materials, known as a heterojunction structure, is fundamentally different from that of the crystalline silicon wafer cell, described above. Tom Baines, ... Jonathan D. Major, in A Comprehensive Guide to Solar Energy Systems, 2018. They are mostly faulted; the thickness of bulk cadmium telluride inner layer is 5 nm (sample F5) and, Advances in Materials Science and Engineering, http://solarlove.org/top-solar-module-manufacturers-2013/, G. K. M. Thutupalli and S. G. Tomlin, “The optical properties of thin films of cadmium and zinc selenides and tellurides,”, B. R. Mehta, S. Kumar, K. Singh, and K. L. Chopra, “Application of spectroscopic ellipsometry to study the effect of surface treatments on cadmium telluride films,”, S. Sirohi, V. Kumar, and T. P. Sharma, “Optical, structural and electrical properties of CdTe sintered films,”, Y. Laaziz, A. Bennouna, N. Chahboun, A. Outzourhit, and E. L. Ameziane, “Optical characterization of low optical thickness thin films from transmittance and back reflectance measurements,”, M. Rusu and G. G. Rusu, “On the optical properties of evaporated CdTe thin films,”, P. D. Paulson and X. Mathew, “Spectroscopic ellipsometry investigation of optical and interface properties of CdTe films deposited on metal foils,”, F. C. Peiris, Z. J. Weber, Y. Chen, and G. Brill, “Optical properties of CdSe, V. Odarych, A. Sarsembaeva, F. F. Sizov, and M. Vuychik, “Determination of parameters of cadmium telluride films on silicon by the methods of main angle and multiangular ellipsometry,”, K. N. Kornienko, V. A. Odarych, L. V. Poperenko, and M. V. Vuichyk, “Determination of optical parameters of CdTe films by principal angle ellypsometry,”, E. R. Shaaban, N. Afify, and A. El-Taher, “Effect of film thickness on microstructure parameters and optical constants of CdTe thin films,”, Y. Bilevych, A. Soshnikov, L. O. Darchuk et al., “Influence of substrate materials on the properties of CdTe thin films grown by hot-wall epitaxy,”, A. Other . Ellipsometric analysis of CdTe films grown on Si and CdHgTe substrates at the “hot-wall” epitaxy vacuum setup has been performed. Hazards to workers may arise from feedstock preparation, fume and vapor leaks, etching of excess materials from panels, maintenance operations (e.g., scraping and cleaning), and during waste handling. The described analysis was performed for all the films and at various wavelengths from visible and near ultraviolet spectral ranges. Cadmium telluride Optical Window, 25.4mm (1.0in) dia x 2mm (0.08in) thick. Cadmium telluride (CdTe) (Bonnet (2012))is a direct-bandgap semiconductor with that bandgap well matched to the solar spectrum. First Solar (USA) leads the production of CdTe modules (2.47 m2) delivering on average 17% efficiencies with a current annual production capacity reaching around 3 GW, which is due to be scaled up to 7 GW by 2019. University of New South Wales, With permission. No comparisons were made with the parent Cd and Te substances. Sarat Kumar Sahoo, ... Narendiran Sivakumar, in Perovskite Photovoltaics, 2018. and Ho, J. Although they are thought of as completing the junction, it has been reported that the choice of metal used to contact this ZnTe layer can affect the solar cell properties. Optical constants spectra for film F3 depending on the film thickness in different places. In the frames of this one-layer model, film optical constants in the short-wave range seem to depend on thickness; that is, they are different at places with different thicknesses. Obviously, optical constants for majority films, calculated using the one-layer model, are found in the diagram region that lies outside the range of values corresponding to the cavities filled with air and oxide (area between the curves 1 and 2). So, for films with the sputtering time minutes the majority thickness conforms to the mixture of cadmium telluride and impurities, which decreases both refractive index and index of extinction. Results of our analysis concerning cadmium telluride films on the CdHgTe substrate are presented in Figure 3. Raman scattering studies revealed the presence of CdTephase over the entire range of RF power studied. The spectra for films with thicknesses less than 70 nm, studied both in this paper and in our earlier publications [8, 9], practically match by main maximum locations with the spectra for bulk monocrystalline cadmium telluride. 8.24). Cadmium, one of CdTe precursors, is a highly hazardous material. In conformity with it, the absorption band also shifts to the long-wave spectral range. Sign up here as a reviewer to help fast-track new submissions. The outer layer of CdTe films grown on CdHgTe (Figure 5(b)) corresponds to the mixture of cadmium telluride and its oxide for majority films. Limited animal data comparing the acute toxicity of CdTe, CIS, and CGS, showed that from the three compounds, CdTe has the highest toxicity and CGS the lowest [7]. Specifically, Figure 4 shows that characteristic peculiarities of the cadmium telluride spectrum shift to the long-wave region by the value up to 150 nm. In principle, the main attraction of CdTe as a candidate for solar energy absorbing material is the value of its separation energy between the conduction and valence bands, energy of the “gap,” which is 1.4 eV and is corresponds to the optimal theoretical value for the use of the solar spectrum, so the interest of the scientific community was great about it in such a way that in a few years its study went from the laboratory scale to preindustrial development (Fig. Optical constants of this equivalent film depend on the volume fraction of cavities, filling material, and they could be calculated using the theory of effective medium in Bruggeman or Maxwell-Garnett approximations [19]. In our opinion, the obtained data could be explained by films’ heterogeneity along their thickness. CdTe always grows as a stoichiometric compound that is much less toxic than Cd metal. Indian Journal of Pure & Applied Physics Vol. These errors occur as a consequence of small number of places with different thicknesses and at worst can amount to the value . PV solar cells based on CdTe represent the largest segment of commercial thin-film module production worldwide. The task of determination of two-layer system six parameters, refractive indexes, indexes of extinction, and layer thicknesses, is difficult in performing, and its success is limited by ellipsometric function distortion in experimental data limits and by multiplicity of solutions. Their flexible property and lightweight sputtering bulk layer is chosen, for films with parent! Concerning the system structure that simplifies procedure of parameters determination 1 and cadmium telluride structure, respectively efficiencies have made. About the shape of relief for films ’ surface could be represented by a layer with rough surface that,. 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