Influences of the iron ion (Fe3+)-doping on structural and optical properties of nanocrystalline TiO_2 thin films prepared by sol-gel spin coating

摘要

Titanium dioxide (TiCb) thin films doping of various iron ion (Fe3+) concentrations were deposited on silicon (Si) (100) and quartz substrates by sol-gel Spin Coating technique followed by a thermal treatment at 600 °C. The structure, surface morphology and optical properties, as a function of the doping, have been studied by X-ray diffractometer (XRD), Raman, ultraviolet-visible (UV-vis) and Spectroscopic Ellipsometry (SE). XRD and Raman analyzes of our thin films show that the crystalline phase of TiC>2 thin films comprised only the anatase TiO_2, but the crystallinity decreased when the Fe3+ content increased from 0% to 20%. During the Fe3+ addition to 20%, the phase of TiO_2 thin film still maintained the amorphous state. The grain size calculated from XRD patterns varies from 29.3 to 22.6 nm. The complex index and the optical band gap (£g) of the films were determined by the spectroscopic ellipsometry analysis. We have found that the optical band gap decreased with an increasing Fe3+ content.