Spray pyrolysis deposition of zinc ferrite films from metal nitrates solutions

Well-crystallized spinel ZnFe2O4 thin films with good adhesion have been su ccessfully prepared on glass substrates heated above 350 degreesC by a spra y pyrolysis deposition from mixed zinc and iron nitrates aqueous solutions. The solution pH has an influence on the surface morphology of ZnFe2O4 film s. A smooth and dense surface was obtained from the mixed solution with a p H of 2.0, while a rough and inhomogeneous surface could be observed from th e solution with a pH of 8.0. The crystallite size of ZnFe2O4 films was foun d to be small, ranging from 10 to 21 nm as calculated from X-ray diffractio n patterns, which is of interest for magnetic material applications. The in direct and direct band gap energies of the sprayed films were estimated to be 1.78 and 2.70 eV, respectively. A schematic illustration is proposed to show the possible deposition processes of ZnFe2O4 thin films by spray pyrol ysis. (C) 2001 Published by Elsevier Science B.V. All rights reserved.