Optical properties of zinc oxide coating with an anisotropic network of nickel fibers

Transparent electrodes are a special class of materials that have high electrical conductivity and transparency in the visible wavelength range. These are key elements of various devices, such as solar batteries, touch screens, etc. Previously, transparent electrodes were made of a fragile and non-ecological material – indium tin oxide (ITO). ITO has a low surface resistance of 10–25 Ohm/sq and a transmittance of more than 90%. However, the complexity of the production technology and high cost pushes researchers to find a replacement for indium tin oxide. In this paper, ZnO/NiFs films obtained by introducing an oriented network of nickel fibers (NiFs) into a thin layer of zinc oxide ZnO while maintaining its transparency in the optical range are considered an alternative to ITO. In the course of the work, a comparative analysis of the optical properties of zinc oxide films and ZnO/NiFs films with different numbers of ZnO layers was carried out. The results obtained by optical spectroscopy show that the transparency coefficient T550 of ZnO films, depending on the number of layers, lies in the range of 90–92%. Compared with a pure ZnO film, the value of the transparency coefficient T550 of the developed ZnO/NiFs system is 85%. Also, for ZnO and ZnO/NiFs films, the absorption spectra in the region of the intrinsic absorption edge were analyzed, and the band gap Eg was estimated. It was shown that the value of the band gap for zinc oxide films lies in the range of 3.23–3.26 eV. For ZnO/NiFs films, an insignificant decrease in the integral value of the band gap is observed, which lies in the range of 3.18–3.25 eV.