Al–Ca co-doped ZnO nanostructures for enhanced electrical and dielectric properties
8 affiliations
- 1Department of Physics, College of Science, Majmaah University, Al-Majmaah, 11952, Saudi Arabia
- 2i3N and Physics Department, University of Aveiro, Campus Universitário de Santiago, Aveiro, 3810-193, Portugal
- 3Department of Physics, College of Science, Qassim University, Buraidah, 51452, Saudi Arabia
- 4Department of Chemistry, College of Science, Taibah University, Taibah, Al-Madinah Al- Munawarah 30002, 42353, Saudi Arabia
- 5Chemistry Department, Women's College for Arts Science and Education, Ain Shams University, Cairo, 11566, Egypt
- 6Department of Chemistry College of Science , Taibah University , Al-Madinah Al-Munawarah , 30002, Saudi Arabia
- 7Department of Physics, College of Sciences, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, 11623, Saudi Arabia
- 8i3N and Physics Department, University of Aveiro, Campus Universitário de Santiago, Aveiro, 3810-193, Portugal. [email protected]
Abstract
In this work, Al (1%) and Ca (5%) co-doped ZnO (ACZO) nanopowders were successfully synthesized using a modified sol-gel method combined with supercritical ethanol drying followed by thermal annealing. X-ray diffraction confirmed that all samples crystallize in the hexagonal wurtzite structure, with a reduction of the crystallite size from 52 nm for pure ZnO to 29 nm for ACZO due to lattice distortion induced by co-doping. SEM and EDS analyses revealed a porous morphology and a homogeneous distribution of Al and Ca within the ZnO matrix. Electrical measurements showed a clear thermally activated semiconducting behaviour, with conductivity following Jonscher's universal power law and improved charge transport in the co-doped sample compared to undoped ZnO. The activation energy extracted from DC conductivity (112 ± 5 meV) and from modulus relaxation (96 ± 5 meV) are very close, confirming that both conduction and relaxation arise from the same hopping mechanism of localized charge carriers. Impedance, Nyquist, dielectric and modulus analyses all demonstrate that Al-Ca co-doping reduces grain boundary resistance, enhances carrier mobility, and improves dielectric response. These results highlight the effectiveness of dual doping in tuning the structural and electrical properties of ZnO for potential applications in electronic, sensing, and energy devices.
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BibTeX
@article{althumairi2026alca,
title = {{Al–Ca co-doped ZnO nanostructures for enhanced electrical and dielectric properties}},
author = {Nouf Ahmed Althumairi and Imen Hammami and Sonia Soltani and H. Marzougui and R. A. El‐Kasaby and Mokhtar Hjiri and Majdi Benamara and S. Soreto Teixeira and M.P.F. Graça and Manuel Almeida Valente},
journal = {Scientific Reports},
year = {2026},
month = jul,
doi = {10.1038/s41598-026-61523-5},
url = {https://doi.org/10.1038/s41598-026-61523-5},
note = {CC BY},
}
RIS
TY - JOUR
TI - Al–Ca co-doped ZnO nanostructures for enhanced electrical and dielectric properties
AU - Nouf Ahmed Althumairi
AU - Imen Hammami
AU - Sonia Soltani
AU - H. Marzougui
AU - R. A. El‐Kasaby
AU - Mokhtar Hjiri
AU - Majdi Benamara
AU - S. Soreto Teixeira
AU - M.P.F. Graça
AU - Manuel Almeida Valente
PY - 2026
DA - 2026/07/24
JO - Scientific Reports
DO - 10.1038/s41598-026-61523-5
UR - https://doi.org/10.1038/s41598-026-61523-5
AB - In this work, Al (1%) and Ca (5%) co-doped ZnO (ACZO) nanopowders were successfully synthesized using a modified sol-gel method combined with supercritical ethanol drying followed by thermal annealing. X-ray diffraction confirmed that all samples crystallize in the hexagonal wurtzite structure, with a reduction of the crystallite size from 52 nm for pure ZnO to 29 nm for ACZO due to lattice distortion induced by co-doping. SEM and EDS analyses revealed a porous morphology and a homogeneous distribution of Al and Ca within the ZnO matrix. Electrical measurements showed a clear thermally activated semiconducting behaviour, with conductivity following Jonscher's universal power law and improved charge transport in the co-doped sample compared to undoped ZnO. The activation energy extracted from DC conductivity (112 ± 5 meV) and from modulus relaxation (96 ± 5 meV) are very close, confirming that both conduction and relaxation arise from the same hopping mechanism of localized charge carriers. Impedance, Nyquist, dielectric and modulus analyses all demonstrate that Al-Ca co-doping reduces grain boundary resistance, enhances carrier mobility, and improves dielectric response. These results highlight the effectiveness of dual doping in tuning the structural and electrical properties of ZnO for potential applications in electronic, sensing, and energy devices.
SN - 2045-2322
ER -