Caracterização estrutural, morfológica e estequiométrica de filmes finos de óxidos de vanádio

Abstract

The application of small angles X-Ray diffraction to the determination of thin film morfology is presented. Technical instrumental aspects that are relevant to the extraction of the diffraction data in this range have been studied and are reviewed in the initial chapter. The basic tools to the low angle analysis, that include effects of x rays refraction at sample surface appears in the following chapter. These effects, that usually are not considered in the interpretation of high angles diffractograms, are taken into account in the software used to perform simulations of the experimental data from models. This simulation is exemplified for some thin films, where surface and interface roughness, interdiffusion and thickness have been sucessfully quantified. In contrast, VO 2 thin films diffractograms did not present any peak at low angle. This can be explained by the high roughness due to the specific kind of growth of these films, as revealed by atomic force microscopy images.