Impact of zinc on the physical and morphological properties of sputtered copper oxide thin films

In this study, thin films of pure and zinc (Zn) doped copper oxides were successfully deposited on a glass sub-strate via reactive magnetron sputtering at varying Zn concentrations. The effects of oxygen/argon ratio and dopant dosage on the structure, morphology, and topography of films were analyzed by the X-ray diffraction technique (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray fluorescence (XRF), Raman, and atomic force microscopy (AFM). The investigations through XRD and Raman revealed the formation of CuO, and Cu2O phases during the copper oxide deposition at 20% oxygen partial pressure, while an increase in the oxygen partial pressure up to 50% resulted in the formation of single-phase CuO. XRD spectra of the Zn-doped films indicated the monoclinic structure of CuO with a gradual increase in the cell volume from 91A3 in the undoped sample to 123 A3 in the sample with a high dopant concentration. By increasing the applied RF power from 10 to 40 W, the cationic ratio (Zn/Zn + Cu) increased from 0.007 to 0.039. AFM analysis figured out the decrease of surface roughness from 11.04 nm in the undoped sample to 3.57 nm in the highly Zn-doped sample. In FESEM images, semi-spherical particles with uniform distribution were observed. By increasing the oxygen partial pressure from 20% to 40% in undoped samples, the average grain size was reduced from 110 to 68 nm, but doping by Zn did not affect the grain size significantly.

Automated summary

In this study, pure and zinc-doped copper oxide thin films were successfully deposited on a glass substrate using reactive magnetron sputtering. The effects of oxygen/argon ratio and dopant dosage on the structure, morphology, and topography of the films were analyzed. It was found that different oxygen partial pressures resulted in the formation of different phases of copper oxide, and doping with zinc affected the crystal structure and cell volume of the films. The applied RF power and Zn concentration also influenced the cationic ratio and surface roughness of the films, respectively. However, the grain size was not significantly affected by Zn doping.