Evaluation of the physical, optical, and electrical properties of SnO₂: F thin films prepared by nebulized spray pyrolysis for optoelectronics

Fluorine-doped tin oxide (SnO₂:F, FTO) thin films were prepared by the nebulized spray pyrolysis technique on glass substrates using tin(IV) chloride pentahydrate (SnCl₂·5H₂O) and ammonium fluoride (NH₄F) as source materials. Different volumes of solvent were used to prepare the spray solution, and their effects on structural, optical, morphological, and electrical properties were investigated. X-ray diffraction patterns revealed the polycrystalline tetragonal structure of FTO films. FESEM images demonstrated well-aligned trigonal-shaped nano-grains. Optical band gap values were estimated to be in the range of 3.71–3.66 eV by Tauc’s plot. The effects of solvent volume on the resistivity, conductivity, carrier concentration, mobility, and figure of merit of FTO films were examined. The lowest electrical resistivity and sheet resistance values were 1.90 × 10⁻⁴ Ω cm and 4.96 Ω/cm, respectively.