Polycrystalline SnS thin films were grown on glass substrates using a novel procedure involving a chemical reaction between the precursor species evaporated simultaneously. This is a relatively new material, which exhibits excellent properties to be used as absorbent layer in solar cells. X-ray diffraction (XRD) measurements indicate that the synthesized samples grow in several phases (SnS, SnS 2 and Sn 2 S 3 ) depending upon the deposition conditions. However, through an exhaustive parameter study, conditions were found to grow thin films predominantly in the SnS phase with orthorhombic structure. It was found that this type of compound presents p-type conductivity, a high absorption coefficient (greater than 10 4 cm −1 ) and an energy band gap E g of about 1.3 eV, indicating that this compound has good properties to perform as absorbent layer in thin film solar cells.

Mo thin films have been deposited using a DC magnetron sputtering system with an S-gun configuration electrode and characterized electrically and morphologically. The influence of the sputtering gas pressure and glow discharge (GD) power, on the electrical resistivity of Mo thin films and on the contact resistivity of Mo to Cu(In,Ga)Se 2 (CIGS) films was determined through an exhaustive parameter study. This study also allowed us to find the conditions to deposit Mo films with suitable properties for its use as back contact of solar cells based on CIGS. Resistivities smaller than 1x10 −4 Ω.cm and contact resistivities smaller than 0.3 Ωcm 2 were found. Mo films with these characteristics are suitable for back contacts in solar cells based on CIGS. It was also found that the Mo thin films, deposited by DC magnetron sputtering on CIGS thin films, act effectively as ohmic contacts. The main contribution of this work was to obtain Mo thin films with adequate properties to be used as back contact for CIGS based solar cells using a DC sputtering system with S-gun configuration electrode, which allows growing the film with better surface quality and at a higher deposition rate than those deposited using the conventional planar RF sputtering system.

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