Kesterite thin films of Cu2ZnSnS4 obtained by spray pyrolysis

Thin films of Cu2ZnSnS4 CZTS were deposited using the spray pyrolysis method as relatively fast and vacuum free method. Obtained samples were analyzed using the X Ray Fluorescence, grazing incidence X Ray Diffraction and Raman Spectroscopy techniques. Analysis showed close to stoichiometry composition of the films with kesterite type structure but poor crystalline quality and possible existence of secondary phases. To improve the quality of the films, the as prepared layers were annealed in the presence of elemental Sn and S. Comparison of the results before and after annealing showed a strong improvement of the crystalline quality and a significant reduction of concentration of secondary phases of the films without significant change of composition. The measured optical band gap is equal to 1.52 and 1.55 eV in the as prepared and annealed films, respectively. The optical absorption coefficient is found to be gt; 10 4 cm

Silicon solar cells based on pSi/nSi3N4 nanolayers

Thin films of Si3N4 were prepared by non-reactive magnetron sputtering in an Ar atmosphere. A previously synthesized Si3N4 was used as a solid-state target. Deposition was carried out on a cold substrate of p-Si (100) with a resistivity of 2 Ohm cm. The Raman spectrum of the deposited Si3N4 layers has been investigated. The position of the maximum in the Raman scattering spectrum of Si3N4 layers corresponds to the Si3N4 compound and the shape of the spectrum is characteristic for the nanocrystalline state of the cubic modification of silicon nitride.The film thickness has been determined from atomic force microscopy measurements. The results of electron diffraction investigations of n-Si3N4 nanolayers with thicknesses up to 20 nm demonstrates that as-deposited Si3N4 thin films consist of a mixture of microcrystalline and amorphous phases.Solar cells based on heterostructures consisting of a p-type Si (100) and n-type Si3N4 nanolayers were fabricated and studied. Keywords: Photovoltaic cells, Heterostructures, Magnetron sputtering, Si3N4 thin film