Nanocrystalline haematite thin films by chemical solution spray

Haematite thin films were prepared by spraying ethanolic solution of iron tri-chloride onto tin-doped indium oxide (ITO) coated glass substrates. The spray time, spray rate, pressure of carrier gas, etc were optimized to obtain nanocrystalline thin films. The films were adherent, smooth, compact and pinhole free. The films were characterized for their structural, morphological, optical and compositional properties. X-ray diffraction studies show that films are nanocrystalline alpha-Fe2O3 having haematite phase. SEM shows that the film consists of elliptical grains randomly distributed with average grain size of about 40-45 nm. The optical band gap was found to be 2.0 eV. Compositional uniformity was confirmed by Auger emission spectroscopy. Annealing the films at 380 degrees C for half an hour increases the particle size.