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The authors have developed a simple, cheap and reproducible technology for obtaining thin-film heterostructures based on CdTe with a given surface morphology during vacuum deposition, which contributes to their low cost [1, 2]. The critical dimensions (thicknesses) of individual layers of the heterostructure were substantiated, a simulation was performed and a wide range of optical properties was investigated [3]. It is shown that for the deposited CdS / CdTe heterostructure on glass it is possible to obtain an efficiency of 15.8%. Given that thin films are relatively new systems, their study can offer much wider opportunities for technological improvement of photovoltaic energy converters. According to the analysis of modern literature data, the efficiency can be increased by performing deposition on ITO films and introducing nanoparticles of controlled sizes.

In this paper, the technology of obtaining and effect of annealing on the morphology and optical properties of cadmium telluride thin films has been investigated. The effect of vacuum chamber modes on the growth of thin films has been studied. For obtained cadmium telluride thin films were used a modified thermal evaporation method deposited by Physical Vapor Deposition technique on a glass substrate with different thicknesses. The transmission measurements were carried with UV-ViS-NIR Spectrophotometer in the wavelength range 180-3300 nm, to analyze the optical properties as a function of wavelength. The optical band gap values were 1.49 eV for as-grown films and 1.46 eV after annealing. The refractive indexes of the samples were defined in the range of 2.6 – 2.8 for as-grown films and the indexes have increased after annealing depending on the wavelength region and film thickness. After annealing, the coalescence mode of growth is observed.

Ellipsometric parameters of CdTe films prepared by "hot-wall" vacuum-epitaxy method on single crystal Si substrates were measured at the wavelength of 632.8 nm. Refractive index, extinction coefficient and thickness of the films were determined. Based on the Maxwell--Garnett approximation of inhomogeneous material containing inclusions of different components (cavities, oxides) the refractive indices and extinction coefficients of effective media were calculated. Optical parameters of the film were found to depend on its thickness, which could be explained by different volume concentration of the substance in the film depth. [ABSTRACT FROM AUTHOR]