Investigation of the effect of S/In molar ratio on physical properties of sprayed In₂S₃ thin films

Indium sulfide (In₂S₃) thin films have been synthesized on glass substrates using the spray technique (CSP). The S : In molar ratio was varied from 1 to 4 in the starting solution. The Raman analysis confirms the formation of the β-In₂S₃ material and the absence of a secondary phase. The EDS analysis reveals that our layers are pure. The thin film surface is free of cracks, as observed in AFM images. Optical transmission achieved 80% in the visible and near infrared region. The refractive index (n) is affected by the changes in the S/In molar ratio. The optical parameters, single oscillator energy (E ₀), dispersion energy (E _d) and high frequency dielectric constant (ε _∞), are calculated via the Wemple-DiDomenico model. In addition, the photoconductivity kinetics in In₂S₃ films for S/In = 2 were investigated and analyzed. The I-V characteristics and the photoresponse were also studied.