Characteristics and optical properties of iron ion (Fe~(3+))-doped titanium oxide thin films prepared by a sol-gel spin coating

摘要

Titanium dioxide (TiO_2) thin films doping of various iron ion (Fe~(3+)) concentrations have been prepared on a glass substrate by the sol-gel spin coating process. Characteristics and optical properties of TiO_2 thin films doping of various Fe content were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV-vis) and spectroscopic ellipsometry. The crystalline phase of TiO_2 thin films comprised only the anatase TiO_2, but the crystallinity decreased when the Fe~(3+) content increased from 0 to 25.0 wt percent. During the Fe~(3+) addition to 25.0 wt percent, the phase of TiO_2 thin film still maintained the amorphous state. The absorption edge of TiO_2 thin films shifted towards longer wavelengths (i.e. red shifted) from 355 to 415 nm when the Fe~(3+)-doped concentration increased from 0 to 25.0 wt percent. The values of the refractive index (n), and extinction coefficient (k), decreased with an increasing Fe~(3+) content. Moreover, the band-gap energy of TiO_2 thin films also decreased from 3.29 to 2.83 eV with an increase in the Fe~(3+) content from 0 to 25.0 wt percent.