Effect of substrate temperature on the crystal growth orientation of SnO2:F thin films spray-deposited on glass substrates

Transparent conducting thin films of SnO2:F have been deposited onto preheated glass substrates by a spray pyrolysis technique using dihydrate stannous chloride (SnCl2·2H2O) and ammonium fluoride (NH4F) as precursors, and mixture of water and ethanol as solvent. The preheated substrate temperature was changed from 250 °C to 600 °C. X-ray diffraction spectra show that the as-deposited films are polycrystalline SnO2 with a tetragonal crystal structure. Surface morphology, optical properties (such as transmission, color), and conductivity were investigated using Super depth of three-dimensional field microscopy system, UV–VIS–NIR spectroscopy, Four-point probe. The obtained results revealed that the structures and properties of the films were greatly affected by substrate temperature. The lowest sheet resistance of 4.0 Ω was obtained with moderate optical transmission (up to 75% at 600 nm). The relationship between the crystal growth orientation and surface morphology, optical properties (such as transmission, color), and electrical properties, was discussed in detail in this article.