Construction of internally stacked Cu₂O:CuO layers in Cu₂O:CuO/Gr/ZnO heterojunctions for solar cells applications

Abstract The present work shows the construction of CuO grains on the electrodeposited Cu2O layer through annealing method and the photovoltaic effect of Cu2O:CuO/ZnO heterojunctions with graphene buffer layer is also discussed. The annealing temperature of Cu2O layer is varied from 100 to 300 °C. The graphene monolayer was deposited by chemical vapor deposition method. The morphology, structural and electrical properties of Cu2O layer were characterized by using Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HR-TEM), X-ray Diffractometry (XRD) and I-V measurement, respectively. The Cu2O grains size increase as the annealing temperature increased and the CuO grains could be observed at 300°C. The graphene monolayer was successfully inserted in between Cu2O:CuO/ZnO heterojunction. The Cu2O:CuO/Gr/ZnO heterojunction shows high electrical rectification with threshold voltage of 0.5 V.