Investigating the role of embedded ZnO seed layer thickness in electrodeposited Cu${}_2$O/Zn${}_{\left(x\right)}$Mg${}_{(1-x)}$O/ZnO/FTO heterojunctions for photovoltaic applications

This article represents the construction of Cu${}_2$O/Zn${}_{\left(x\right)}$Mg${}_{(1-x)}$O/ZnO/FTO heterojunctions by employing a simple electrodeposition approach. The impact of inserting ZnO seed layers with different thicknesses on the various physicochemical properties of the electrodeposited films is explored by applying various techniques. The electrochemical characterization specifies high photoresponses achieving 335.42 µA cm${}^{-2}$ for seeded Cu${}_2$O/Zn${}_{\left(x\right)}$Mg${}_{(1-x)}$O heterojunctions by increasing the thickness of seeded ZnO layer from 25 to 100 nm. The scanning electron microscopy and atomic force microscopy techniques indicate that the surface texture and smoothness of Cu${}_2$O/ZnO heterojunctions have significantly enhanced after increasing the thickness of the ZnO layers. The synthesized ZnO nanostructures are found to be highly crystalline in nature having ZnO with hexagonal phase oriented along (002) direction and Cu${}_2$O with cubic structure oriented along (111) direction. This study shows the introduction of ZnO seed layers, enhances the I-V characteristics of Au/Cu${}_2$O/Zn${}_{\left(x\right)}$Mg${}_{(1-x)}$O/ZnO/FTO solar cells. The ideality factor shows a decreasing tendency from 5.35 to 3.93 while the photoelectric response is increased from 427% to 643% with the increase of the ZnO thickness from 25 to 100 nm, respectively, demonstrating the effectiveness of the seed layers approach. (© 2024 Wiley‐VCH GmbH)