Microstructure and functional properties of Sr-doped K0.5Na0.5NbO3 thin films
Authors
Vojisavljević, KatarinaPečnik, Tanja
Uršič, Hana
Matavž, Aleksander
Bobnar, Vid
Malič, Barbara
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The legislation against the use of lead-based piezoelectric materials in electronics has stimulated an increased research in the field of the lead-free piezoelectric ceramics and thin films after 2003. Among lead-free materials, special attention was paid to some compositions of potassium sodium niobate solid solution, K0.5Na0.5NbO3 (KNN) obtained by a partial replacement of A- and B- site atoms from the perovskite KNN crystal lattice with dopants. Excellent piezoelectric and ferroelectric properties of chemically modified KNN ceramics indicate that they can be used as the efficient lead-free counterparts to lead-based piezoelectrics.
Although A-site doping of KNN ceramics with low amounts of alkaline earths (Ca2+, Sr2+, Ba2+), particularly with Sr2+ was reported as an useful way in improvement of their density and electrical properties [1, 2], there is no literature data concerning the microstructure and functional properties of KNN thin films influenced by the same chemical modifica...tion.
In this contribution, liquid precursors of (K0.5Na0.5)1-ySryNbO3 (KNN-ySr) thin-films, where the Sr- dopant content was set at y = 0, 0.005, 0.01, were prepared from potassium and sodium acetates and niobium ethoxide in 2-methoxyethanol solvent with 5 mole % of potassium acetate excess, and an appropriate amount of strontium acetate dissolved in acetic acid. The approximately 250 nm thick KNN-ySr thin films on Pt/TiOx/SiO2/Si substrates were obtained through repeated spin-coating and pyrolysis steps at 300 oC for 2 min, followed by the rapid thermal annealing at 650 oC in air flow for 5 min with a heating rate of 12 K/s.
According to X-ray diffraction analysis, all of the synthesized KNN thin films crystallize in pure perovskite phase with (100) preferential orientation. The surface and cross-section microstructure analysis, performed by the field emission scanning electron microscopy, reveals that the KNN-ySr films consist of equiaxed grains, the average size of which gradually decreases from about 90 nm to a few tens of nm by increasing the Sr-dopant content. Dielectric properties versus frequency, polarisation – electric field dependence and leakage current were followed in order to get information on how the Sr-dopant content influences the functional properties of the as-prepared films. In addition, the topography and the local piezoelectric response of the KNN-ySr films were analysed by atomic force microscopy coupled with a PFM mode.
References:
[1] B. Malič, J. Bernard, J. Holc, D. Jenko, M. Kosec, Alkaline-earth doping in (K,Na)NbO3 based piezoceramics, J. Eur. Ceram. Soc. 25 (2005) 2707-2711.
[2] M. Demartin Maeder, D. Damjanović, N. Setter, Lead free piezoelectric materials, J. Electroceram. 13 (2004) 385-392.
Keywords:
(K0.5Na0.5)1-ySryNbO3 / sol-gel synthesis / thin films / FE-SEM / PFMSource:
COST TO-BE. Fall Meeting, 2016, 89-89Publisher:
- Ljubljana, Slovenia/Jožef Stefan Institute
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Institution/Community
Institut za multidisciplinarna istraživanjaTY - CONF AU - Vojisavljević, Katarina AU - Pečnik, Tanja AU - Uršič, Hana AU - Matavž, Aleksander AU - Bobnar, Vid AU - Malič, Barbara PY - 2016 UR - http://rimsi.imsi.bg.ac.rs/handle/123456789/2894 AB - The legislation against the use of lead-based piezoelectric materials in electronics has stimulated an increased research in the field of the lead-free piezoelectric ceramics and thin films after 2003. Among lead-free materials, special attention was paid to some compositions of potassium sodium niobate solid solution, K0.5Na0.5NbO3 (KNN) obtained by a partial replacement of A- and B- site atoms from the perovskite KNN crystal lattice with dopants. Excellent piezoelectric and ferroelectric properties of chemically modified KNN ceramics indicate that they can be used as the efficient lead-free counterparts to lead-based piezoelectrics. Although A-site doping of KNN ceramics with low amounts of alkaline earths (Ca2+, Sr2+, Ba2+), particularly with Sr2+ was reported as an useful way in improvement of their density and electrical properties [1, 2], there is no literature data concerning the microstructure and functional properties of KNN thin films influenced by the same chemical modification. In this contribution, liquid precursors of (K0.5Na0.5)1-ySryNbO3 (KNN-ySr) thin-films, where the Sr- dopant content was set at y = 0, 0.005, 0.01, were prepared from potassium and sodium acetates and niobium ethoxide in 2-methoxyethanol solvent with 5 mole % of potassium acetate excess, and an appropriate amount of strontium acetate dissolved in acetic acid. The approximately 250 nm thick KNN-ySr thin films on Pt/TiOx/SiO2/Si substrates were obtained through repeated spin-coating and pyrolysis steps at 300 oC for 2 min, followed by the rapid thermal annealing at 650 oC in air flow for 5 min with a heating rate of 12 K/s. According to X-ray diffraction analysis, all of the synthesized KNN thin films crystallize in pure perovskite phase with (100) preferential orientation. The surface and cross-section microstructure analysis, performed by the field emission scanning electron microscopy, reveals that the KNN-ySr films consist of equiaxed grains, the average size of which gradually decreases from about 90 nm to a few tens of nm by increasing the Sr-dopant content. Dielectric properties versus frequency, polarisation – electric field dependence and leakage current were followed in order to get information on how the Sr-dopant content influences the functional properties of the as-prepared films. In addition, the topography and the local piezoelectric response of the KNN-ySr films were analysed by atomic force microscopy coupled with a PFM mode. References: [1] B. Malič, J. Bernard, J. Holc, D. Jenko, M. Kosec, Alkaline-earth doping in (K,Na)NbO3 based piezoceramics, J. Eur. Ceram. Soc. 25 (2005) 2707-2711. [2] M. Demartin Maeder, D. Damjanović, N. Setter, Lead free piezoelectric materials, J. Electroceram. 13 (2004) 385-392. PB - Ljubljana, Slovenia/Jožef Stefan Institute C3 - COST TO-BE. Fall Meeting T1 - Microstructure and functional properties of Sr-doped K0.5Na0.5NbO3 thin films EP - 89 SP - 89 UR - https://hdl.handle.net/21.15107/rcub_rimsi_2894 ER -
@conference{ author = "Vojisavljević, Katarina and Pečnik, Tanja and Uršič, Hana and Matavž, Aleksander and Bobnar, Vid and Malič, Barbara", year = "2016", abstract = "The legislation against the use of lead-based piezoelectric materials in electronics has stimulated an increased research in the field of the lead-free piezoelectric ceramics and thin films after 2003. Among lead-free materials, special attention was paid to some compositions of potassium sodium niobate solid solution, K0.5Na0.5NbO3 (KNN) obtained by a partial replacement of A- and B- site atoms from the perovskite KNN crystal lattice with dopants. Excellent piezoelectric and ferroelectric properties of chemically modified KNN ceramics indicate that they can be used as the efficient lead-free counterparts to lead-based piezoelectrics. Although A-site doping of KNN ceramics with low amounts of alkaline earths (Ca2+, Sr2+, Ba2+), particularly with Sr2+ was reported as an useful way in improvement of their density and electrical properties [1, 2], there is no literature data concerning the microstructure and functional properties of KNN thin films influenced by the same chemical modification. In this contribution, liquid precursors of (K0.5Na0.5)1-ySryNbO3 (KNN-ySr) thin-films, where the Sr- dopant content was set at y = 0, 0.005, 0.01, were prepared from potassium and sodium acetates and niobium ethoxide in 2-methoxyethanol solvent with 5 mole % of potassium acetate excess, and an appropriate amount of strontium acetate dissolved in acetic acid. The approximately 250 nm thick KNN-ySr thin films on Pt/TiOx/SiO2/Si substrates were obtained through repeated spin-coating and pyrolysis steps at 300 oC for 2 min, followed by the rapid thermal annealing at 650 oC in air flow for 5 min with a heating rate of 12 K/s. According to X-ray diffraction analysis, all of the synthesized KNN thin films crystallize in pure perovskite phase with (100) preferential orientation. The surface and cross-section microstructure analysis, performed by the field emission scanning electron microscopy, reveals that the KNN-ySr films consist of equiaxed grains, the average size of which gradually decreases from about 90 nm to a few tens of nm by increasing the Sr-dopant content. Dielectric properties versus frequency, polarisation – electric field dependence and leakage current were followed in order to get information on how the Sr-dopant content influences the functional properties of the as-prepared films. In addition, the topography and the local piezoelectric response of the KNN-ySr films were analysed by atomic force microscopy coupled with a PFM mode. References: [1] B. Malič, J. Bernard, J. Holc, D. Jenko, M. Kosec, Alkaline-earth doping in (K,Na)NbO3 based piezoceramics, J. Eur. Ceram. Soc. 25 (2005) 2707-2711. [2] M. Demartin Maeder, D. Damjanović, N. Setter, Lead free piezoelectric materials, J. Electroceram. 13 (2004) 385-392.", publisher = "Ljubljana, Slovenia/Jožef Stefan Institute", journal = "COST TO-BE. Fall Meeting", title = "Microstructure and functional properties of Sr-doped K0.5Na0.5NbO3 thin films", pages = "89-89", url = "https://hdl.handle.net/21.15107/rcub_rimsi_2894" }
Vojisavljević, K., Pečnik, T., Uršič, H., Matavž, A., Bobnar, V.,& Malič, B.. (2016). Microstructure and functional properties of Sr-doped K0.5Na0.5NbO3 thin films. in COST TO-BE. Fall Meeting Ljubljana, Slovenia/Jožef Stefan Institute., 89-89. https://hdl.handle.net/21.15107/rcub_rimsi_2894
Vojisavljević K, Pečnik T, Uršič H, Matavž A, Bobnar V, Malič B. Microstructure and functional properties of Sr-doped K0.5Na0.5NbO3 thin films. in COST TO-BE. Fall Meeting. 2016;:89-89. https://hdl.handle.net/21.15107/rcub_rimsi_2894 .
Vojisavljević, Katarina, Pečnik, Tanja, Uršič, Hana, Matavž, Aleksander, Bobnar, Vid, Malič, Barbara, "Microstructure and functional properties of Sr-doped K0.5Na0.5NbO3 thin films" in COST TO-BE. Fall Meeting (2016):89-89, https://hdl.handle.net/21.15107/rcub_rimsi_2894 .