Optical, XPS and XRD Studies of Semiconducting Copper Sulfide Layers on a Polyamide Film

Copper sulfide layers were formed on polyamide PA 6 surface usingthe sorption-diffusion method. Polymer samples were immersed for 4and 5 h in 0.15 mol⋅ dm−3 K2S5O6 solutions and acidified with HCl(0.1 mol⋅ dm−3) at 20∘C. After washing and drying, the samples were treated with Cu(I) salt solution. The samples were studied byUV/VIS, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. All methods confirmed that on thesurface of the polyamide film a layer of copper sulfide was formed. The copper sulfide layers are indirect band-gap semiconductors. The values of bg are 1.25 and 1.3 eV for 4 h and 5 h sulfured PA 6 respectively. Copper XPS spectra analyses showed Cu(I) bonds only in deeper layers of the formed film, while in sulfur XPS S 2p spectra dominating sulfide bonds were found after cleaning the surface with Ar+ ions. It has been established by the XRD method that, beside Cu2S, the layer contains Cu1.9375S aswell. For PA 6 initially sulfured 4 h, grain size for chalcocite,Cu2S, was ∼35.60 nm and for djurleite, Cu1.9375S, it was 54.17 nm. The sheet resistance of the obtained layer varies from 6300 to 102 Ω/cm2