PREPARATION OF YVO4 THIN-FILMS BY METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION

YVO4 films were reproducibly prepared on (0001) and (<11(2)over bar 0> ) sapphire (alpha-Al2O3) substrates using metal organic chemical vapor deposition. X-Ray diffraction, transmission electron microscopy and X -ray energy dispersive spectroscopy were used to characterize the depo sited films. It was found that under most growth conditions the films deposited on (0001) sapphire consisted of two layers, i.e. a stoichiom etric bottom layer of YVO4 which was epitaxially grown on the substrat e and a polycrystalline top layer of Y8V2O17. The effect of growth par ameters, in particular the growth temperature, on the stability of the dual layer structured films was studied and a working model explainin g the origin of dual layer structure was suggested. Based on these obs ervations the method for the preparation of stoichiometric epitaxial o ne layer-structured YVO4 films with either an in-plane variant or a si ngle crystal structure on (0001) and (<11(2)over bar 0>) sapphire (alp ha-Al2O3) substrates, respectively, was presented. (C) 1998 Elsevier S cience S.A. All rights reserved.