Growth and Property Characterization of Monoclinic CuO Coatings

The monoclinic CuO films were deposited by magnetron sputtering on glass substrate.The effect of the O₂/Ar ratio on the microstructures and optical properties was investigated with X-ray diffraction, scanning electron microscopy and spectrophotometer.The results show that the O₂/Ar ratio had a major impact.To be specific, as the O₂/Ar ratio increased, the poly-to mono-crystalline transition occurred, accompanied by a decrease of the <-111> preferential growth orientation; the CuO coatings, grown in anisotropic manner, became increasingly compact and smooth; the compressive stress along a-and b-axis changed in an increase-leveloff mode, while the compressive stress transited into tensile stress in c-axis; a slight blue-shift of the optical absorption edge near 1.9 e V of the direct-gap CuO semiconductor showed up, possibly because of quantum size effect of CuO grains.