MECHANISM OF CURRENT TRANSFER IN nСdS-pCdTe SOLAR CELLS HETEROSTRUCTURES

Abstract

The material, fabrication and operation parameters for cadmium telluride CdTe солнечных элементов require high sensitivity, small pixel size, low defect density, long-term thermal-cycling reliability and large area substrates. The focus of this work is on the epitaxial growth of CdTe thin films on Si(111) for the purpose of using the resulting material as a substrate for the solar cell .In contrast, polycrystalline CdTe grown for solar cell applications, results in CdTe grown predominately in the (111) orientation . A photosensitive nSi/pCdTe heterojunction based on single-crystalline silicon has been obtained and studied. As substrates, we used n-type silicon single-crystal wafers Si<111>, with a thickness d=300÷350 μm, on the surface of which thin layers of p-type CdTe with conductivity d=50÷70 μm were deposited in a vacuum quasi-closed volume. The resulting CdTe films had a cubic structure. The study of the nSi/pCdTe heterostructure by energy-dispersive X-ray diffraction analysis showed that the composition of the CdTe layer depends on its thickness on the silicon surface. The spectral characteristics of the formed heterostructure were also obtained, where the decline of the maximum located in the long-wavelength region of the spectrum corresponds to silicon, and the decline of the maximum located in the short-wavelength region corresponds to cadmium telluride and covers a wide region - from the visible region of the spectrum to the infrared region (300 ÷ 1400 nm).