Influence of Ni doping on the morphological, structural, optical and electrical properties of CuO thin films deposited via a spray pyrolysis

Nanostructured copper oxide (CuO) and Nickel (Ni)-doped CuO thin films with different concentrations of Ni ranging from 2 to 8 at.% were synthesized onto a plain glass substrate at the substrate temperature, 350 degrees C by a thermal spray pyrolysis technique. Field emission scanning electron microscopy (FESEM) analysis of CuO and Ni-doped CuO thin films detected the closely spaced rock-like nanostructures, evenly distributed on the film surfaces. The average particle sizes of CuO and Ni-doped CuO thin films were calculated from the FESEM and found between 260 and 63 nm. Energy-dispersive X-ray analysis revealed that CuO and Ni-doped CuO thin films were stoichiometric and typically comprised of Cu, O, and Ni. X-ray diffraction analysis showed the monoclinic structure of the films with the most preferred orientation plane ((1) over bar 11) along with the (111), ((2) over bar 02) and (02 (2) over bar) crystalline planes. The maximum crystallite size was found at about 81 nm for 6 at% Ni-doped CuO thin film. CuO film showed an optical transmittance of about 33% in the visible-NIR region. Ni-doping enhanced the absorbing nature of CuO thin films in the vis-NIR region of light. With the rise of Ni content in CuO thin films, the optical bandgap gradually increased from 2.28 to 2.78 eV. Resistivity raised from 9.28 x 10(3) to 49.01 x 10(3) Omega-cm with the increase of the amount of Ni.

Automated summary

Nanostructured copper oxide and nickel-doped copper oxide thin films were synthesized with varying nickel concentrations and characterized. The nickel doping improved the light absorbance in the visible-NIR region, leading to an increase in the optical bandgap with higher nickel content. The resistivity also increased with the rise in nickel concentration in the copper oxide thin films.