Influence of Ag concentration on the structure, optical and electrical properties of SnS₂:Ag thin films prepared by spray pyrolysis deposition

Abstract

Ag-doped tin-sulfide thin films were deposited with in spray pyrolysis method at T = 425 °C on soda lime glass substrates. The effects of Ag doping were investigated on the structural, optical, and electrical properties of thin films. Double deionized water was used as a precursor solution in which tin chloride (SnCl₄5H₂O) and thiourea (CS(NH₃)₂) in addition to silver acetate (AgC₂H₃O₂) were dissolved. All in all resulted to preparation of SnS₂:Ag thin films with $\frac{{\left[ {\text{Ag}} \right]}}{{\left[ {\text{Sn}} \right]}}\% = 0, \,1, \,2, \,3\, {\text{and}} \,4\,{\text{at}}.\%$. The (001) plane is the preferred orientation of the SnS₂ phase which is analyzed by X-ray diffraction (XRD). The intensity of mentioned peak has an increasing trend, generally, with increasing Ag doping concentration. Thin films have spherical grains as is shown in SEM images. Increasing doping concentration from 1 to 4%, causes decrease in: single-crystal grains from 14.68 to 6.31 nm, optical band gap from 2.75 to 2.62 eV, carrier concentration from 3.11 × 10¹⁷ to 2.58 × 10¹⁷ cm⁻³, and Hall mobility from 1.81 to 0.13 cm²/v s, as well as increase in: average grain size, generally, from 70 to 79 nm and electrical resistance from 11.11 to 181.26 Ω cm, respectively. The majority carriers are electrons for these films as is concluded from Hall Effect measurements.