GISAXS: Grazing incidence angle selection applied to a nanostructured ZnO film

Abstract

One of the parameters involved in the Grazing Incidence Small Angle X-Ray Scattering (GISAXS) experimental arrangement is the incidence angle. Usually when a sample is studied by GISAXS, several 2D images are taken at different incidence angles, but for a matter of time consumption, only one of them is chosen to be analyzed, according to the intensities of the pattern. But: If another image had been chosen, would the same results have been obtained? Are these values obtained from the analyzed image really representative of the sample? The main goal of this article is to find out the appropriate range of angles of incidence for which the scattering of the pores embedded in the film is well evident, as well as to verify if in this range the information obtained from each GISAXS images with different angles of incidence offers an equivalent description of the porosity of the studied sample. A nanostructured ZnO film synthesized by sol-gel and deposited by spin-coating was characterized by XRD, FESEM and GISAXS. In the present work, the information arising from GISAXS patterns (pores size and their distribution and aspect ratio) of a ZnO film is analyzed for different incidence angles for the purpose of determining a suitable range. The reliable conditions are obtained for angles between the critical angle and the lowest angle that allows the incident radiation to penetrate the total thickness. In this range the results remain constant, as expected.