Study of RF sputtered Cu3SbS4 thin-film solar cells

We report on the fabrication and characterization of polycrystalline Cu₃SbS₄ thin films grown by magnetron sputtering. We find that Cu₃SbS₄ thin films deposited at various temperatures show the Famatinite structure and high optical absorptions with band gaps of slightly lower than 1.0 eV and weak absorptions centered at about 0.9 eV. The as deposited thin films have very small grains and low carrier density. Sulfurization results in increased hole density, but does not increase the grain size. Due to the film decomposition and sublimation, the deposition and sulfurization are limited to temperatures below 300 °C. Our best small area Cu₃SbS₄-based thin-film solar cell shows a conversion efficiency of only 0.46% under AM1.5 illumination. We believe that the small grain size is partially responsible for the poor cell performance.