A study of the structural, optical, and electrical properties of SnS₂:Cu optical semiconductor thin films deposited by the spray pyrolysis technique

Abstract

Cu-doped tin-sulfide thin films were deposited onto glass substrates at T = 400 °C through spray pyrolysis. The effects of Cu doping on the structural, optical, and electrical properties of the thin films were investigated. The precursor solution was prepared by dissolving tin chloride (SnCl₄·5H₂O) and thiourea (CS(NH₃)₂) in deionized water and then adding copper chloride (Cl₂Cu₂H₂O). SnS₂:Cu thin films were prepared with $\frac{{\left[ {Cu} \right]}}{{\left[ {Sn} \right]}}\% = 0, 1, 2, 3, 4 \,{\text{at}}.\%$. X-ray diffraction analysis showed that the thin films had a preferred (001) orientation of the SnS₂ phase and that the intensity of the (001) peak decreased with increased doping concentration from 1–4 at.%. Scanning electron microscopy studies indicated that the thin films had spherical grains. Characterization results of thin films showed that single-crystal grains, average grain size, optical band gap, carrier concentration, Hall mobility, and electrical resistance varied within 5–14 nm, 46–104 nm, 2.81–2.99 eV, 2.42 × 10¹⁶–26.73 × 10¹⁶ cm⁻³, 2.41 × 10⁻³–20.04 × 10⁻³ cm²/v.s, and 9.05–12.89 Ω cm, respectively. Hall effect studies further revealed that the films exhibited n-type conductivity.