Multifaceted tungsten oxide films grown by thermal evaporation

Thermal evaporation, compared to other vapor phase deposition techniques, is a simple low-cost method to obtain films. Multifaceted tungsten oxide microcrystals were grown as films by the thermal evaporation of tungsten trioxide on (100) silicon substrates covered with SiO2 layer, which were arranged vertically inside a horizontal furnace. The structural characterization of these films was carried out through micro-Raman spectroscopy, Xray photoelectron spectroscopy, X-ray diffractometry, scanning electron microscopy and Rutherford backscattering spectrometry. The crystals are composed of monoclinic and hexagonal WO3 phases that grew as plates and were arranged radially around multifaceted nuclei. The films present photocatalytic activity, which is evidenced by the accelerated degradation of methyl orange dye, and are resistant to leaching in aqueous media. This initial characterization will enable further exploration of these films as photocatalysts. (C) 2015 Elsevier B.V. All rights reserved.