Effect of the composition on physical properties of CdTe absorber layer fabricated by chemical molecular beam deposition for use in thin film solar cells

We developed revolutionary novel and low cost and nonvacuum chemical molecular beam deposition method for fabrication of thin film II-VI solar cells in the atmospheric pressure gas (He, Ar, H2) flow. High quality polycrystalline CdTe films with different compositions (stoichiometric and Cd/Te ≤1.0 and Cd/Te ≥ 1.0) and thickness of 2–3 μm were fabricated on ceramic (SiO2:Al2O3) substrates at temperature of 600 °C. Separate sources of Cd and Te with respective purities of 99.999% were used as precursors. The growth rate was varied in the range of 9–30 A/s. The effect of the composition and CdCl2 treatment on the structure, intrinsic point defects, and electrical properties of CdTe films was investigated by XRD, AFM, Raman spectra, photoluminescence, and Hall methods.