Temperature-dependent optical characteristics of sputtered NiO thin films

In this work, nickel oxide thin films were deposited by radio frequency magnetron sputtering technique. X-ray diffraction (XRD), scanning electron microscopy and energy-dispersive X-ray analysis methods were applied to reveal the structural and morphological properties of sputtered thin films. The XRD pattern of films confirmed the presence of the cubic phase of nickel oxide with the preferential orientation of (200) direction. The surface morphology of thin films was observed as almost uniform and smooth. Optical aspects of sputtered film were studied by employing the room temperature Raman and temperature-dependent transmittance spectroscopy techniques in the range of 10-300 K. Tauc relation and derivative spectroscopy techniques were applied to obtain the band gap energy of the films. In addition, the relation between the band gap energy and the temperature was investigated in detail considering the Varshni optical model. The absolute zero band gap energy, rate of change of band gap energy, and Debye temperature were obtained as 3.57 eV, - 2.77 x 10(-4) eV/K and 393 K, respectively.

Automated summary

Nickel oxide thin films were deposited using the radio frequency magnetron sputtering technique. The structural and morphological properties of the films were analyzed using X-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive X-ray analysis. The films were found to have a cubic phase of nickel oxide with a preferential orientation of (200) direction, and the surface morphology was observed to be uniform and smooth. Optical properties of the films were studied using Raman spectroscopy and temperature-dependent transmittance spectroscopy, and the band gap energy of the films was obtained using Tauc relation and derivative spectroscopy techniques. Furthermore, the relationship between the band gap energy and temperature was investigated using the Varshni optical model, and the absolute zero band gap energy, rate of change of band gap energy, and Debye temperature were determined as 3.57 eV, - 2.77 x 10(-4) eV/K, and 393 K, respectively.