Dependence of the optical and structural properties of ZnO:Al nanostructured layers deposited electrochemically on seeding multilayer stack substrates

Abstract

We report studies on the optical and structural properties of nanostructured ZnO layers doped with Al (ZnO NW) electrochemically grown on conductive substrates, namely, ZnO:Al/Ag/ZnO:Al multilayer stack structures deposited on glass substrates. Multilayer transparent conductive stack structures with different thickness of the middle Ag film (10 nm, 16 nm and 20 nm) with plasmonic properties were prepared by magnetron sputtering of ZnO:Al and Ag targets. Additionally, a seeding stack annealed at 180 °C for 50 min was prepared in order to study the influence of the seeding stacks properties – resistivity and structure, on the optical and structural characteristics of the electrochemically-grown ZnO layers. A correlation was observed between the surface roughness and the diffuse reflection and the haze ratio in reflection. The results are discussed in terms of the influence of the size of the Ag grains and their distribution in the middle Ag film in the seeding stacks on the nucleation and growth of ZnO NW. The ZnO NW layers exhibited higher values of the diffuse reflection in the 400 – 1100 nm spectral range; they can be applied as rear contacts of thin films solar cells thus increasing the light trapping.