Effect of Fluorine Concentration on Structural, Electrical and Optical Properties of SnO2:F Thin Films Orepared by Spray Pyrolysis Technique

Abstract

Fluorine doped tin oxide, SnO₂: F (FTO) thin films deposited on glass substrates at 405±2˚C have been prepared using Spray Pyrolysis Technique. Structural, electrical and optical properties of FTO thin films under different doping concentration (5, 15, 20, 25 and 30) wt% are investigated using XRD patterns, Hall effect measurement and UV–Vis spectrophotometry. X-ray diffraction studies of FTO films indicate that all films are polycrystalline with tetragonal structure. The lattice constants a and c vary from (4.7269 to 4.7557)Å and (3.2548 to3.2103) Å respectively. While the crystallite size D varies from 8.07 to 7.85 nm. Electrical measurements showed that all the films are of n-type conductivity. Carriers mobility (μ), concentration of carrier (n) and resistivity (ρ) reached 6.05 cm²/Vs, 5.62x10¹⁹cm^-3 and 8.79x10^-2 Ω cm, respectively. The energy gap decrease from 3.9 to 3.78 eV with increase fluorine concentration from (5-30) wt% respectively. FTO films can be used as conducting layers(Electrodes) in photovoltaic devices.