Abstract
This report investigated the structural, optical and electrical properties of V-doped SnO2 thin films deposited by the spray pyrolysis technique. The SnO2:V films, with different V- content, were deposited on glass substrates at substrate temperature of 550 ◦C using an aqueous–ethanol solution consisting of tin and vanadium chloride. X-ray diffraction studies showed that the SnO2:V films were polycrystalline only with tin oxide phases and preferential orientations along (110), (101), (211) and (301) planes. The grain sizes were estimated to fall within the range of 25–36 nm, using Scherrer formula. Field Emission Scanning Electron Microscopy (FESEM) revealed the surface morphology to be very smooth, yet grainy in nature. Optical transmittance spectra of the films showed high transparency about ~69–90% in the visible region, decreasing with increase in V-doping. The direct band gap for undoped SnO2 films was found to be 3.53 eV, while for higher V-doped films shifted toward lower energies in the range 3.27–3.53 eV and then increased again to 3.50 eV. The sign of the Hall voltage and Seebeck coefficient was observed for films n-type. The thermal activation energy, Seebeck coefficient and maximum of photosensitivity in the films were found in the range 0.02-0.82 eV (in the low temperature range), 0.15-0.18 mVK−1 (at T = 350 K), 0.96-2.84, respectively.