1：Experimental Design and Method Selection:

Copper oxide thin films were deposited on glass substrates with fluorine doped tin oxide (FTO) conductive electrodes by using r-HIPIMS. The plasma reactor chamber was continuously evacuated by the turbomolecular and rotary vane pump. Argon and oxygen were fed into the reactor chamber via gas flow controllers. A planar unbalanced magnetron with a circular magnetron cathode and a copper target was used as the metal source.

2：Sample Selection and Data Sources:

Glass substrates with a SnO2:F (FTO) layer were used.

3：List of Experimental Equipment and Materials:

A HiPIMS power supply with the maximum current in pulse 200 A and the maximum average power of 2 kW was used for r-HiPIMS discharge excitation. The RF Sobolewski probe was used for the measurement of ion flux density jion on the substrate during the deposition.

4：Experimental Procedures and Operational Workflow:

The substrate holder was electrically floating and was rotating along its center with the velocity of 1 RPM. The substrate was not heated by any external heater during the depositions.

5：Data Analysis Methods:

The thickness of the films was determined by profilometry measurements. The deposited films were analyzed by XRD before and after the annealing. Photoelectrochemical measurements were done by the use of potentiostat.