Preparation and properties of KCl-doped Cu2O thin film by electrodeposition

With the indium tin oxide-coated glass as working electrode, cuprous oxide thin film is fabricated by means of electrodeposition. The effects of KCl doped and annealing treatment upon Cu2O thin film morphology, surface resistivity, open-circuit voltage, electric conduction types and visible light response are studied. The research results indicate that KCl doped has a great effect upon Cu2O crystal morphology, thus, making Cu2O thin film surface resistivity drop, and the open-circuit voltage increase and that electric conduction types are transformed from p type into n type, and the visible light (400–500 nm) absorption rate is slightly reduced. Annealing treatment can obviously decrease Cu2O thin film surface resistivity and improve its open-circuit voltage. When KCl concentration in electrolytic solution reaches 7 mmol/L, Cu2O thin film morphology can be changed from the dendritic crystal into the cubic crystal and Cu2O thin film surface resistivity decreases from the initial 2.5 × 106 Ω cm to 8.5 × 104 Ω cm. After annealing treatment at 320 °C for 30 min, the surface resistivity decreases to 8.5 × 102 Ω cm, and the open-circuit voltage increases from the initial 3.1 mV to 79.2 mV.