Electrical properties of niobium doped titanium dioxide thin films by spin coating technique

Undoped TiO₂ and Niobium (Nb)-doped TiO₂ thin films have been successfully prepared and deposited on glass substrate by spin coating technique. The effect of annealing temperature on electrical properties using I-V measurement of Titanium Dioxide thin films was studied. TiO₂ thin films were annealed at 300°C to 550°C. The results indicated that the conductivity increased while resistivity decreased with the increasing of annealing temperatures. Using 450°C as an optimum annealing temperature that has been examined, the effect of Nb doping concentrations on electrical properties was investigated. As the doping concentration of Nb was increased, the resistivity decreased and conductivity was increased. Optical properties of TiO₂ thin films were investigated using UV-vis-NIR spectrophotometer and indicated that the optical band gap increased with increasing Nb doping concentration. The FESEM investigation showed that the thin films consist of nanometer-sized grain particles.