Characterization and gas-sensing properties of nanocrystalline iron(III) oxide films prepared by ultrasonic spray pyrolysis on silicon

Thin films of nanocrystalline hematite (α-Fe2O3) are deposited on silicon substrates by nebulization of a 0.01 M solution of iron acetylacetonate in an ethanol/water mixture, followed by pyrolysis and annealing in flowing air. The resulting films are characterized by X-ray diffraction, scanning electron microscopy, atomic force microscope, IR transmission spectrum and Raman Spectra, and the gas-sensing properties of as-deposited films are investigated as well. The resulting films consist of spherical particles and porous, columnar order structure for Si(111) with several nm order of magnitude of crystal grain size, and highly crystalline α-Fe2O3 films with (104) orientation are obtained.