Preparation and Characterization of Transparent Conducting FTO Thin Films by Chemical Spray Pyrolysis Method

Fluorine doped tin oxide (FTO) thin films were synthesized by chemical spray pyrolysis method on glass substrates for 10 at.%, 15 at.%, 20 at.% of fluorine doping concentrations. Their structural, optical and electrical properties were investigated. X-ray diffraction (XRD) study shows polycrystalline nature of the films with orthorhombic crystal structure. The grain size (D) was observed in the range of 14 nm to 30 nm. The FESEM images of the FTO thin films reveals that the films have smooth and homogeneous surface morphology with thin granular grains distributed throughout the surface. EDX analysis confirms the presence of Sn, O and F elements in the prepared FTO thin films. Photoluminescence (PL) spectrum shows a broad emission which covers near band edge (NBE) as well as deep level emissions (DLE) in the region 380 nm and 620 nm. From the hall effect measurements, it was observed that all the films exhibit n-type conductivity. The sample grown with 10 at. % of fluorine showed the highest transmission percentage (80%) with high mobility and conductivity, which are basic requirements for a TCO.