Influence of oxygen flow rate and substrate positions on properties of Cu-oxide thin films fabricated by radio frequency magnetron sputtering using pure Cu target

Cu oxide thin films have been deposited by radio frequency magnetron sputtering in an ambient of argon and oxygen using a pure Cu target. The structural, electrical and optical properties were investigated systematically as a function of O-2 flow rate and substrate positions, revealing that the O-2 flow rate and substrate positions have a strong influence on both composition and functional properties of the resulting Cu oxide films. Particularly, the films tend to change towards Cu2O, Cu4O3 and CuO single and bi-phase with increasing the O-2 flow rate. Optical absorption properties were analyzed for the single phase Cu2O, Cu4O3, and CuO films prepared in this study, demonstrating the potential of Cu4O3 and CuO as an absorber material for the photovoltaic application.