Oxygen-vacancy induced ferroelectricity in nitrogen-doped nickel oxide
American Institute of Physics
This paper reports the onset of ferroelectricity in NiO by breaking the crystallographic symmetry with oxygen vacancies created by N doping. Nitrogen-doped NiO was grown at room temperature by RF sputtering of Ni target in Ar–O2–N2 plasma on silicon and fused silica substrates. The impact of the nitrogen doping of NiO on microstructural, optical, and electrical properties has been investigated. According to x-ray diffraction investigations, by increasing the N doping level in NiO, a transition from (002) to a (111) preferential orientation for the cubic NiO phase was observed, as well as a lattice strain relaxation, that is usually ascribed to structural defect formation in crystal. The x-ray diffraction pole figures the presence of a distorted cubic structure in NiO and supports the Rietveld refinement findings related to the strain, which pointed out that nitrogen doping fosters lattice imperfections formation. These findings were found to be in agreement with our far-infrared measurements that revealed that upon nitrogen doping a structural distortion of the NiO cubic phase appears. X-ray photo-emission spectroscopy measurements reveal the presence of oxygen vacancies in the NiO film following nitrogen doping. Evidence of ferro-electricity in nitrogen-doped NiO thin films has been provided by using the well-established Sawyer–Tower method. The results reported here provide the first insights on oxygen-vacancy induced ferroelectricity in nitrogen-doped nickel oxide thin films.
Oxygen-vacancy induced ferroelectricity , Nitrogen-doped nickel oxide thin films
Dragoman, M., Vulpe, S., Aperathithis, E., Aivalioti, C., Romanitan, C., Dinescu, A., Dragoman, D., Aldrigo, M., Djourelov, N., Modreanu, M. and Moldovan, A. (2022) 'Oxygen-vacancy induced ferroelectricity in nitrogen-doped nickel oxide', Journal of Applied Physics, 131(16), 164304 (11pp). doi: 10.1063/5.0075568
© 2022, the Authors. Published under an exclusive license by AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared as: Dragoman, M., Vulpe, S., Aperathithis, E., Aivalioti, C., Romanitan, C., Dinescu, A., Dragoman, D., Aldrigo, M., Djourelov, N., Modreanu, M. and Moldovan, A. (2022) 'Oxygen-vacancy induced ferroelectricity in nitrogen-doped nickel oxide', Journal of Applied Physics, 131(16), 164304 (11pp), doi: 10.1063/5.0075568 and may be found at https://doi.org/10.1063/5.0075568