Titanium dioxide (TiO2) films with a thickness of 550nm were deposited on quartz glass at 300 °C by metalorganic chemical vapor deposition. The effects of post-annealing between 600°C and 1000°C were investigated on the structural and optical properties of the films. X-ray diffraction patterns revealed that the anatase phase of as-grown TiO2 films began to be transformed into rutile at the annealing temperature of 900°C. The TiO2 films were entirely changed to the rutile phase at 1000°C. From scanning electron spectroscopy and atomic force microscopy images, it was confirmed that the microstructure of as-deposited films changed from narrow columnar grains into wide columnar ones. The surface composition of the TiO2 films, which was analyzed by X-ray photoelectron spectroscopy data, was nearly constant although the films were annealed at different temperatures. When the annealing temperature increased, the transmittance of the films decreased, whereas the refractive index and the extinction coefficient calculated by the envelope method increased at high temperature. The values of optical band gap decreased from 3.5 eV to 3.25 eV at 900 °C. This abrupt decrease was consistent with the anatase-to-rutile phase transition.
|Number of pages||6|
|Journal||Applied Physics A: Materials Science and Processing|
|Publication status||Published - 2001 Nov|
All Science Journal Classification (ASJC) codes
- Materials Science(all)