Influence of thiourea in the precursor solution on the structural, optical and electrical properties of CZTS thin films deposited via spray coating technique

CZTS films were prepared by spray coating using non-aqueous precursor solutions with and without sulphur source and studied their structural, optical and electrical properties. The films prepared by both the routes were sulphurized at different temperatures to study the effect of temperature on the phase formation. Phase purity was confirmed by XRD, Raman analysis and Rietveld refinement technique. The studies revealed proper phase and crystallinity for the films of both routes sulphurized at 550 °C. These films exhibited dense and improved grain structure, optimal bandgap and higher absorption coefficient. The non-thiourea films sulphurized at 550 °C had a carrier concentration of 1.544 × 10 19 cm −3 , mobility of 0.87 cm 2 V −1 s −1 and resistivity of 0.46 Ω·cm, while the thiourea films achieved carrier concentration, mobility and resistivity of 3.67 × 10 19 cm −3 , 0.33 cm 2 V −1 s −1 and 0.52 Ω·cm, respectively. The comparative study demonstrates that the films under investigation have the potential for the fabrication of efficient solar cells.