Solvent-dependent growth of sprayed FTO thin films with mat-like morphology

Highly textured fluorine-doped tin oxide thin films have been deposited using cost-effective spray pyrolysis technique. Precursor solution for spraying is prepared with solvents viz. methanol, ethanol, propane-2-ol and distilled water. The optical, structural, morphological and electrical properties of thin films have been studied. X-ray diffraction studies revealed polycrystalline tin-oxide (SnO2) phase with tetragonal crystal structure and predominantly (2 0 0) oriented films, irrespective of solvents. The novel mat-like morphology is observed by scanning electron microscope (SEM). Hall-effect measurements revealed that the films are heavily doped degenerate semiconductor with n-type conductivity. The variations in electrical resistivity, carrier concentration and mobility with respect to spray solvents have been discussed. The typical PFTO sample has maximum value of figure of merit (φ=6.18×10−2 Ω−1) with lowest ever-reported sheet resistance of 3.71 Ω.