Properties of Na0.5Bi0.5TiO3 ferroelectric films prepared by chemical solution decomposition
Introduction
Lead oxide-based piezoelectric materials, represented by PbTiO3, Pb(Zr,Ti)O3, Pb(Mg,Nb)O3, etc, have been rapidly developed and widely used. However, they are opposite to the needs of environmental protection because of lead pollution. Therefore, from the viewpoint of sustaining development of the world society, it is necessary and urgent to search for lead-free piezoelectric materials.
Sodium bismuth titanate Na0.5Bi0.5TiO3 (abbreviated as NBT) belongs to one of a few ferroelectric complex perovskite-type compounds with two different ions at the A site of the ABO3 structure. Although NBT was first discovered in 1961 by Smolensky [1], it has recently attracted attention as an excellent candidate for a key material of lead-free piezoelectric material, which exhibits excellent ferroelectric properties [2], [3], [4]. Some studies about NBT have been performed, such as piezoelectric and ferroelectric properties [5], [6], and the optical behavior [7]. All these studies are mainly about single crystal or ceramic. However, research on NBT thin films has rarely been reported [8]. In this paper, we report the growth and properties of polycrystalline NBT thin films by a chemical solution decomposition method.
Section snippets
Experimental procedure
Thin films of NBT were fabricated using bismuth acetate, sodium acetate and tetrabutyl titanate as materials. Glacial acetic acid and ethylene glycol monomethyl ether were selected as solvents. Bismuth acetate was initially dissolved in glacial acetic acid. Sodium acetate was dissolved in ethylene glycol monomethyl ether. The solutions were stirred constantly during heating. Then both solutions were mixed with constantly stirring. Tetrabutyl titanate was added to this mixture, stirred for about
Results and discussion
The infrared-absorption spectrum of NBT has been measured for powder samples dispersed in pressed KBr disks. Brown powders were obtained after 150 °C drying. With increasing treatment temperature, the powders became somewhat yellowish. Fig. 1 shows the infrared (IR) spectrum of powders dried at different temperature in air for 1 h. It can be seen that absorption bands of precursor solution dying at 150 °C are strong. The band at 1022 cm−1 is the bending mode of the Ti–O–R group. The bands present
Conclusions
In conclusion, NBT thin films have been successfully prepared by chemical solution decomposition and deposited on p-Si(1 1 1) substrate and Pt/TiO2/SiO2/Si substrates by spin coating. X-ray diffraction and atomic force microscopy measurements show that the films present perovskite phase and consist of homogeneous grains of 120 nm size. The insulating property of negative bias voltage is better than that of positive bias voltage. The NBT thin films exhibit a typical hysteresis loop with an applied
Acknowledgements
We acknowledge the support of the Natural Science Foundation of China under Grant nos. 50172031 and 60278036.
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2018, Journal of the European Ceramic SocietyCitation Excerpt :However, up to now, few studies have focused on BNT thin films. Films were prepared by different methods: RF sputtering [15,16], sol-gel [17–21], laser ablation [22–24]. Although growth parameters, dielectric and ferroelectric properties for BNT thin films were discussed, piezoelectric properties at the macroscopic scale were rarely investigated [16,25].
Influence of oxygen gas pressure on phase, microstructure and electrical properties of sodium bismuth titanate thin films grown using pulsed laser deposition
2015, Thin Solid FilmsCitation Excerpt :Extensive investigations on bulk NBT have enabled thin film studies which lead to device applications. Various deposition techniques such as sol–gel process [1–6], r-f magnetron sputtering [7] and pulsed laser deposition [8,9] have been used to deposit NBT thin films. In our previous study, Taguchi method was used to optimize pulsed laser deposition (PLD) growth parameters in order to obtain single phase and high-quality NBT thin films [10].
Efficient photocatalytic removal of nitric oxide with hydrothermal synthesized Na<inf>0.5</inf>Bi<inf>0.5</inf>TiO<inf>3</inf> nanotubes
2014, Journal of Alloys and CompoundsCitation Excerpt :Na0.5Bi0.5TiO3 was generally synthesized by conventional solid-state method, but this method usually results in a high agglomeration powders as a result of the high-temperature treatment [19]. In comparison with solid-state techniques, the hydrothermal technique has superior advantages such as versatility, well controlled morphology, high purity and narrow particle size distribution of the prepared powders [23–26]. For instance, Dai reported that Na0.5Bi0.5TiO3 powders could be hydrothermal prepared using TiCl4 and Bi(NO3)3⋅5H2O as raw materials and NaOH as mineralizer [27].
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2014, Ceramics InternationalCitation Excerpt :Investigations on bulk NBT justify the demand for thin film studies leading to devices applications. A number of investigations have focused on NBT thin films [1–9]; invariably stoichiometry has been achieved only where excess Na and/or Bi have been used. Tang et al. [3] have reported on the preparation and electrical properties of highly (111) oriented NBT thin films by a sol–gel process with the precursor containing 10% excess Bi.
Electrical characterization of sol-gel-derived (1-x)NBT-xNTa (0.05<x<0.3) thin films
2013, Ceramics InternationalCitation Excerpt :Ferroelectric thin films have received a lot of research attention due to their integration into multifunctional devices [1–8].