Influence of the parameters of fabrication on the optical properties of Bi1.7Ti2O6.624 thin films

• We grew bismuth titanium oxide films by rf magnetron sputtering.
• We determined the optical parameters such as refractive index of the bismuth titanium oxide films through Swanepoel method.
• We calculated the absorption coefficient and optical band gap of the bismuth titanium oxide films.

We show the results obtained for the growth of Bi1.7Ti2O6.624 thin films through RF magnetron sputtering. The films were grown on common glass substrate, the microstructure was evaluated for all films as a function of the power applied at the target and the substrate temperature, and the optical behavior was evaluated for the most crystalline film. Microstructure analysis was carried out through X-ray diffraction (XRD), and optical response was evaluated by means of transmittance measurements. The XRD results showed that the films grown in a range from room temperature to 573 K and at a power from 100 W to 200 W are amorphous. Moreover, the films grown at 623 K and power at 150 and 200 W showed preferential orientation along the (311) plane of the Bi1.7Ti2O6.624 cubic-centered face phase. Using the transmittance values and through the Swanepoel method, we calculated the refraction index and the average thickness of the most crystalline film. The refraction index dispersion was studied via the Wemple–DiDomenico relation. The absorption coefficient and the optical band gap were determined through analysis of the free interference region.