Photovoltaic Properties of Electrochemical Deposited Cu2O/ZnO p-n Heterojunction*

In order to fabricate a Cu2O/ZnO heterojunction, single-crystal n-type zinc oxide (ZnO) nanorod arrays and p-type cuprous oxide (Cu2O) thin film were deposited on FTO glass respectively by electrochemical deposition method using an electrochemical workstation. The Cu2O/ZnO heterjunctions were also deposited by electrochemical deposition method. A series of characterization and measurements were taken to indicate its properties. It was found that the diameter of ZnO nanorods increased with the increase of the concentration of ZnCl2 during the deposition of ZnO nanorod arrays. Formation of a p-n junction between Cu2O film and ZnO nanorod arrays were demonstrated through electrical properties measurements. The efficiency of this solar cell was also calculated. The higher external quantum efficiency of the Cu2O/ZnO heterojunctions than that of ZnO nanorod arrays and Cu2O film also indicates the formation of a p-n junction, which can efficiently facilitate the separation and transport of charge carriers for applications in solar cells. But some evidence shows that a weak contact/interface between ZnO nanorods and Cu2O film resulted from solution corrosion may affect its photovoltaic properties.