X-Ray Diffraction Study of Effect of Filler Concentration and Thickness of Poly-p-xylylene–Cadmium Sulphide Nanocomposite Films on Their Structure

— The structure of poly- p -xylylene–cadmium sulfide (PPX–CdS) nanocomposite films of different thickness (~0.2, ~0.5, and ~1 μm) is studied by X-ray diffraction in a wide range of CdS concentrations, as well as the structure of single-component CdS and PPX films of different thickness. The films are obtained by solid-phase cryochemical synthesis on optical quartz and single-crystal silicon substrates. The results of the study show that CdS nanoparticles in PPX-CdS films with a thickness of ~ 0.2 μm with filler content of C ~ 10.5–13.5 vol % and in a CdS film of the same thickness have a crystal structure of a wurtzite type with an average size of coherent scattering regions of ~30 nm in PPX–CdS and ~60 nm in CdS films. For nanocomposite films with a thickness of ~0.2 μm ( C ~ 8 vol %), ~0.5 and ~1 μm ( C ~ 5–90 vol %), as well as for a CdS film with a thickness of ~1 μm, only diffusive diffraction maxima are observed, on the basis of which the conclusion is drawn that the CdS nanoparticles in these films have an amorphous or defective crystal structure and a size of ~1–3 nm. The PPX matrix in all studied nanocomposite films has a low-ordered (amorphous) structure, as in a single-component film of this polymer with a thickness of ~0.5 μm.