Application of atomic layer deposition for obtaining nanostructured ITO/Al$_{2}$O$_{3}$ coatings

In this work, additional nanometer-thick Al$_{2}$O$_{3}$ layers were grown by atomic layer deposition on nanostructured optically transparent conductive indium–tin oxide coatings obtained by electron-beam evaporation. The indium–tin oxide coatings formed by whiskers of predominantly vertical orientation and characterized by an effective refractive index decreasing monotonically in the direction perpendicular to the substrate were used. The effect of deposited Al$_{2}$O$_{3}$ layer thickness on optical characteristics of the obtained samples is studied. It has been shown that the use of atomic layer deposition method allows one to uniformly cover filamentary crystals of thick nanostructured indium–tin oxide films, in which the upper whiskers obscure the underlying ones, with protective shells; as a result, more resistant to the external environment antireflection conducting coatings with the desired parameters can be obtained. When a protective Al$_{2}$O$_{3}$ layer is deposited, the gradient behavior of the refractive index typical for the initial indium–tin oxide film is kept constant.