Effect of Cu Doping on Structural, Optical, and Electrical Properties of Sn₂S₃ Thin Films Prepared by Spray Pyrolysis

The structural, optical, morphological, and electrical properties of polycrystalline copper-doped tin sulfide (Cu-Sn₂S₃) thin films with different concentrations of Cu dopants were synthesized using the spray pyrolysis method. Structural characterizations (powder XRD) revealed orthorhombic Sn₂S₃ crystal structure with Pmma space group. The XRD spectra showed improved crystalline quality and preferential orientation for the Cu-doped Sn₂S₃ thin films. Morphology of the prepared samples revealed sharp needle-shaped grains uniformly distributed throughout the sample. The UV spectroscopy results show 70–75% transmittance for 6 wt.% and 8 wt.% Cu-doped Sn₂S₃ thin films in the visible region. The bandgap values are decreased for the 4 wt.% sample and increased with an increase in the Cu concentration for 2 wt.%, 6 wt.%, and 8 wt.% with Sn₂S₃ thin films. The dielectric constant, dielectric loss, and electrical and optical properties were analyzed using UV data. Negative Hall coefficient values of prepared samples confirm the n-type semiconductor nature. Electrical conductivity increases with an increase in Cu concentration. These results indicate that the samples have potential applications in the optoelectronic field.