Iron doped titania thin films prepared by spin coating

Abstract

Thin films of titania (TiO₂) doped with 1–5 wt-%Fe were spin coated on glass slides and then annealed at 500°C for 2 h. Results revealed that all of the films were ∼500 nm in thickness and consisted of anatase. Increasing the dopant levels revealed the following trends: the major (101) anatase peak shifted to larger lattice spacing [the peaks were normalised using the principal (210) chromium coating peak as an in situ standard]; the microstructures showed increasing shrinkage cracking, a phenomenon that has not been reported previously; the optical transmittance generally decreased; the amplitude of the transmittance curves generally decreased; and the optical indirect band gap decreased from 3·40 to 3·18 eV, possibly due to silicon contamination, residual thermal stress and/or the formation of midgap states from Fe doping.

Keywords:

• Titania
• Spin coating
• Thin film
• Single beam focused ion beam milling
• Glancing angle X-ray diffraction
• Field emission scanning electron microscopy
• UV–vis spectrophotometry
• Indirect band gap

The authors are grateful for the financial support of the Australian Research Council (ARC), which have allowed this and other developmental work to be undertaken. The authors also would like to acknowledge access to the UNSW node of the Australian Microscopy and Microanalysis Research Facility (AMMRF).