Optical, XPS and XRD studies of semiconducting copper sulfide layers on a polyamide film

Abstract

Copper sulfide layers were formed on polyamide PA 6 surface using the sorption-diffusion method. Polymer samples were immersed for 4 and 5h in 0.15mol dm dm-3 K 2 S5 O6 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 by UV/VIS, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. All methods confirmed that on the surface of the polyamide film a layer of copper sulfide was formed. The copper sulfide layers are indirect band-gap semiconductors. The values of E bg are 1.25 and 1.3eV for 4h and 5h 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 Cu 1. 9375 S as well. For PA 6 initially sulfured 4h, grain size for chalcocite, Cu2S, was ∼ 35.60 nm and for djurleite, Cu 1. 9375 S, it was 54.17nm. The sheet resistance of the obtained layer varies from 6300 to 102 ω / cm2. Copyright © 2009 V. Krylova and M. Andrulev̧cius.