Effect of Zr doping on the structural and electrical properties of spray deposited TiO2 thin films

[摘要] Doping is an effective material re-engineering technique, which provides a possibility of improving properties ofmaterials for different applications. Herein, a Zr-doped TiO2 thin film was deposited applying the chemical spray pyrolysismethod and the influence of varying zirconium dopant concentrations on the properties of the film was studied. Morphologicalstudies showed that the Zr–TiO2 films were homogeneous with smaller grain sizes compared to the undoped TiO2 films. AsdepositedZr–TiO2 films were amorphous while the undoped TiO2 films were crystalline with anatase structure as revealedby both X-ray diffraction and Raman spectroscopy studies. The optical band gap of the Zr–TiO2 film was higher (3.44 eV)than that of the undoped TiO2 films (3.13 eV) showing a strong dependence on the phase composition. As revealed by energydispersive spectroscopy analysis, the Zr/Ti ratio in the film increased from 0.014 to 0.13 as the doping concentration in the spraysolution was increased from 5 to 40 mol%. The current–voltage (I–V) characteristic revealed a reduction of the leakage currentin the Zr-doped TiO2 film (6.06 × 10–5 A) compared to the undoped TiO2 films (1.69 × 10–3 A) at 1 forward bias voltage.The dielectric relaxation response at the oxide–electrode interface dipole was strongly influenced by the Zr doping concentrationin the film.

[学科分类] 化学（综合）

[关键词] chemical spray pyrolysis;doping;thin films;dielectric relaxation;Zr–TiO2.