ZnO:Cu Thin Films and p-n Homojunctions Grown by Electrochemical Deposition

ZnO doped with Cu thin films were deposited on indium tin oxide coated glass substrates by electrodeposition using an electrolyte consisting of Cu and Zn perchlorates dissolved in dimethylsulfoxide. The Cu/Zn ratio measured in the thin films is about twice the Cu/Zn ratio present in the starting electrolyte. Irrespective of the Cu content, all the ZnO:Cu films exhibit a hexagonal wurtzite structure typical of ZnO with a preferential orientation along (002) direction. The p-type behaviour of ZnO:Cu films is inferred from the change in the sign of the photocurrent observed for Cu concentrations greater than 2%. Furthermore, a p-n homojunction with a rectifying factor 22 were prepared by electrodepositing of ZnO/ZnO:Cu layers.