Effect of Junction Morphology on the Performance of Polycrystalline Cu2O Homojunction Solar Cells

Cu2O p-n homojunction solar cells were fabricated by the consecutive electrochemical deposition of p-Cu2O layer, followed by n-Cu2O layer. The surface morphology of p-type Cu2O, which determines the p-n junction interface, was modified to investigate its effect on the performance of the homojunction solar cell. The results showed that the junction quality and the cell efficiency varied significantly depending on the crystals faces exposed at the p-n junction, although the resistivity of the p- and n-layers remained comparable. The best performance of the homojunction cell fabricated in this study was V-OC = 0.423 V, I-SC = 2.5 mA/cm(2), fill factor (ff) = 27%, and eta = 0.29%. The main limiting factor for the cell efficiency was the high resistivity of both p- and n-layers. Doping studies and fine-tuning of the junction morphology will be necessary to improve the performance of the Cu2O homojunction solar cells further.