The influence of oxygen pressure on the growth of CuO nanostructures prepared by RF reactive magnetron sputtering

Copper oxide films were prepared by RF reactive magnetron sputtering at different percentages of oxygen pressure in a Ar:O₂ reactive gas mixture at room temperature. The structural and optical properties of CuO films were investigated by a field emission scanning electron microscope, Raman spectroscopy, X-ray diffraction and UV–Visible spectrophotometer. The structure of the deposited film changed from a mixture of Cu₂O + CuO phases to a pure CuO phase with an increase in oxygen percentage. In addition the crystallite size increased from 12 to 24 nm as the oxygen pressure percentage increased. The optical transmittance significantly increased with the increase of the oxygen pressure percentage and the optical band gap of the film increased from 1.33 to 1.41 eV. The film prepared with 30 and 40 % oxygen pressure showed (002) crystallographic orientation. The I–V characteristic of p-CuO/n-Si heterojunction diode was also found to be dependent on the oxygen pressure percentage.