Mechanical and structural properties of Li-doped CuO thin films deposited by the Successive Ionic Layer Adsorption and Reaction method

Abstract Lithium-doped CuO thin films with different concentrations are deposited by the Successive Ionic Layer Adsorption and Reaction technique on glass substrates. The films are characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, UV-Vis. Spectroscopy, nanoindentation and in-situ scanning probe microscopy. Scanning electron microscopy showed uniform film surface and smaller particle size with increasing Li concentration. X-ray diffraction patterns revealed decreasing crystallite size with increasing Li concentration. The Raman spectra revealed CuO phases and a secondary phase of Cu2O at high doping concentrations especially after the concentration of 1.0 at.% Li. UV-Vis. Spectroscopy results indicated that the transmittance and bandgap values could be modified with Li-doping. Both of them are found to be increasing with increasing Li concentration. All indentation test load curves exhibited a smooth shape without any detected pop-in. The results of the nanoindentation test revealed that the nanohardness and elastic modulus increased with Li-doping.