Characterization of Cu2SnS3 thin films prepared by sulfurization of co-evaporated Cu–SnS precursor layers

Highlights: • Cu₂SnS₃ thin films were fabricated on soda-lime glass substrates. • Surface morphology, optical and electrical properties of the Cu₂SnS₃ thin films were examined. • Temperature-dependent electrical properties of the thin film were also analyzed. - Abstract: Monoclinic Cu₂SnS₃ thin films were prepared by sulfurizing Cu–SnS precursor layers deposited by a co-evaporation method on soda-lime glass substrates. The morphological, optical and electrical properties of the Cu₂SnS₃ thin films were investigated by scanning electron microscopy, spectral transmittance, and Hall effect measurements. All Cu₂SnS₃ thin films prepared in this study exhibited p-type conductivity and a direct band gap of 0.86–0.87 eV with a high absorption coefficient (α > 10⁴ cm⁻¹). However, carrier concentrations and electrical resistivities varied noticeably, depending on their metallic composition ratios and sulfurization temperatures. The thin film with a metallic composition ratio [Cu]/[Sn] = 1.66 had a carrier concentration, resistivity, and mobility of 3.12 × 10¹⁷ cm⁻³, 6.37 Ω·cm, and 3.14 cm²/V·s, respectively. The temperature dependence of electrical resistivity, carrier concentration, and Hall mobility of this thin film was also obtained from liquid nitrogen temperature to room temperature to examine charge transport properties.