Growth of void free Cu2ZnSnS4 (CZTS) thin films by sulfurization of stacked metallic precursor films

• Synthesis of void free CZTS thin films using sulfurization of stacked metallic precursors.
• Sulfurized films are a kesterite crystal structure with a void free large grain morphology.
• Sulfur content in the CZTS film decreases at long sulfurization time.
• Sulfurized films show band gap energies in the range of 1.51–1.64 eV.

A void free Cu2ZnSnS4 (CZTS) thin films were grown on Mo-coated glass substrates by using sulfurization of sputtered stack metallic precursor at 580 °C in (N2 + H2S) atmosphere for different sulfurization times ranging from 60 min to 180 min. The effects of sulfurization time on the structural, morphological, chemical and optical properties of the sulfurized CZTS thin films have been investigated. All the sulfurized CZTS thin films exhibit a polycrystalline kesterite crystal structure with a void free densely packed large grain morphology. Compositional study indicates that the Zn/Sn ratio increases with increasing sulfurization time, and for long sulfurization the sulfur content in the film decreases. The band gap energies of the sulfurized CZTS thin films are found to be in the range between 1.51 and 1.64 eV.