Vanadium transition metal oxide films obtained by annealing under room atmosphere of metal layers sequentially deposited

Metallic thin films M/V/M/V... /V/M (M = Fe, Ni) sequentially deposited under vacuum were annealed for 1/2 h in room atmosphere. The samples were characterised by X-rays diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and optical absorption (OA) and near-infrared absorption, The annealing temperature and the substrate were taken as parameters. In addition some pre-annealing treatment was used. The results showed that monoclinic Ni2V2O7 and triclinic FeVO4, homogeneous thin films can be synthesised by this simple technique. Best results were obtained when the glass substrate used was coated with SnO2 thin films. The results were improved when, before air-annealing, a first annealing under vacuum was proceeded in order to homogenise the metal distribution in the sample. (C) 2000 Elsevier Science B.V. All rights reserved.