Physical Properties of Semiconductor TCO-SnO2:F Thin Film

A thin film of SnO2:F (FTO) semiconductor was deposited on a glass substrate using the spray pyrolysis technique. In the sample preparation, a solution of tin dichloride SnCl2·2H2O to which was added ammonium fluoride (0.15 wt. NH4F) was used in order to improve its optical and electrical properties. The films were deposited at a temperature of 475°C. A semiautomated deposition equipment allowed controlling the deposition process. The XRD study revealed that the film is polycrystalline in nature with a cassiterite type structure. The existence of microcrystals with an apparent size of 42.54 ± 0.8 nm and residual microtension in the percentage of 0.10323 ± 0.0028 was observed. The morphological study (SEM) revealed a compact and homogeneous substrate coating. The optical transmittance average in the visible region was 81.3%. The use of the Drude-Lorentz model showed that the film thickness and the optical band gap energy are 516 nm and 4.16 eV, respectively. Finally, the thermal characterization suggested that ρ practically does not change, showing a constant value of 1.56 x 10-3 Ω-cm in the temperature range of 0 to 130 ° C.