X-ray scattering by nano-particles within granular thin films, investigation by grazing angle X-ray reflectometry

It is shown here that the observation of the phenomenon of like small angle scattering of X-rays in very thin heterogeneous films, can be made comparatively easily by using grazing angle reflectometry of X-rays. The feasibility was achieved with co-sputtered thin films of approximately 600 Å thickness, made up by crystalline platinum clusters embedded in an amorphous alumina matrix. The experimental reflectivity profiles are simulated by the intensity superposition of two components: (i) the specular part caused by the usual interference phenomenon between the partial waves reflected from the air-film and film-substrate interfaces, and (ii) the like-small angle scattering part due to diffraction by platinum clusters. It is found that the shape of such clusters is spherical characterized by mean values of diameter $\langle \phi _{c}\rangle$ and inter-cluster distance $\langle S_{c} \rangle$ of the order 29 Å and 45 Å respectively with standard deviations $\sigma _{\phi }$ and $\sigma _{S}$ of the order of 3 Å . Such an observation of both the interference and diffraction phenomena indicates that the thin granular film exhibits both its continuous and heterogeneous aspects together