Study of close space sublimation (CSS) Grown SnS thin-films for solar cell applications

We report ou characterization of SnS thin films grown by high temperature close space sublimation (CSS) method. The CSS grown films are slightly Sn-rich and show high degree of crystalmity with orthorhombic (Herzeubergite) crystal structure. The as deposited SnS has direct transition at about 1.3 eV with a very high absorption (α ~10⁴ cm^-1) in risible light range. Hall measurements in Van der Pau configuration suggest p-type conductivities with carrier concentrations in the order of 10¹⁷ - 10¹⁸ cm^-3. Despite baring poor adhesion, C dS/SnS solar cells synthesized on FTO-coated glass substrates in superstrate configuration have demonstrated non-zero cell efficiencies. With application of SnCl₄ treatment and Au back contact, we achieved a 0.1% cell efficiency with a V_OC of 108 mV, a J_SC of 2.2 mA/cm² and a FF of 36.2%. The large band offsets, high carrier concentration, and poor adhesion are the limiting factors for the solar cell performance.