Dysprosium-doped Bi4Ti3O12 (Bi3.4Dy0.6Ti3O12, BDT) ferroelectric thin films were deposited on Pt(111)/Ti/SiO2/Si(111) substrates by chemical solution deposition (CSD) and crystallized in nitrogen, air and oxygen atmos...Dysprosium-doped Bi4Ti3O12 (Bi3.4Dy0.6Ti3O12, BDT) ferroelectric thin films were deposited on Pt(111)/Ti/SiO2/Si(111) substrates by chemical solution deposition (CSD) and crystallized in nitrogen, air and oxygen atmospheres, respectively. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to identify the crystal structure, the surface and cross-section morphology of the deposited ferroelectric films. The results show that the crystallization atmosphere has significant effect on determining the crystallization and ferroelectric properties of the BDT films. The film crystallized in nitrogen at a relatively low temperature of 650 ℃, exhibits excellent crystallinity and ferroelectricity with a remanent polarization of 2Pr = 24.9 μC/cm2 and a coercive field of 144.5 kV/cm. While the films annealed in air and oxygen at 650 ℃ do not show good crystallinity and ferroelectricity until they are annealed at 700 ℃. The structure evolution and ferroelectric properties of BDT thin films annealed under different temperatures (600?750 ℃) were also investigated. The crystallinity of the BDT films is improved and the average grain size increases when the annealing temperature increases from 600 ℃ to 750 ℃ at an interval of 50 ℃. However, the polarization of the films is not monotonous function of the annealing temperature.展开更多
The Bi4Ti3Oi2 and Bi3.25La0.75Ti3O12 thin films were prepared on the Pt/Ti/SiO2/Si substrate using the sol-gel method. The effect of La doping on the microstructure and ferroelectric properties of Bi4Ti3O12 films were...The Bi4Ti3Oi2 and Bi3.25La0.75Ti3O12 thin films were prepared on the Pt/Ti/SiO2/Si substrate using the sol-gel method. The effect of La doping on the microstructure and ferroelectric properties of Bi4Ti3O12 films were investigated. Both the Bi4Ti3O12 and Bi3.25La0.75Ti3O12 thin films exhibited typical bismuth layered perovskite structure. The 2Pr （remanent polarization） value of Bi3.25La0.75Ti3O12 thin films is 18.6 μC/cm^2, which is much larger than that of Bi4Ti3O12 thin films. And the Bi3.2eLa0.75Ti3O12 films show fatigue-free behavior, while the Bi4Ti3O12 thin films exhibit the fatigue problem. The mechanism of improvement of La doping was discussed.展开更多
Polycrystalline Bi_4Ti_3O_（12） thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt（111）/Ti/Si O_2/Si substrates by laser-ablation under different kinetic growth condit...Polycrystalline Bi_4Ti_3O_（12） thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt（111）/Ti/Si O_2/Si substrates by laser-ablation under different kinetic growth conditions. The relationship between the structure and ferroelectric property of the films was investigated, so as to explore the possibility of enhancing ferroelectric polarization by controlling the preferred orientation. The structural characterization indicated that the large growth rate and high oxygen background pressure were both favorable for the growth of non-c-axis oriented grains in the Bi_4Ti_3O_（12） thin films. The films with high fractions of a-axis and random orientations, i e, f（a-sxis） = 28.3% and f（random） = 69.6%, could be obtained at the deposition temperature of 973 K, oxygen partial pressure of 15 Pa and laser fluence of 4.6 J/cm^2, respectively. It was also noted that the variation of ferroelectric polarization was in accordance with the evolution non-c-axis orientation. A large value of remanent polarization（2 Pr = 35.5 μC/cm^2） was obtained for the Bi_4Ti_3O_（12） thin films with significant non-c-axis orientation, even higher than that of rare-earth-doped Bi_4Ti_3O_（12） films.展开更多
Bi3.25La0.75Ti3O12（BLT）thin films were prepared on Pt/Ti/SiO2/Si substrate by the sol-gel method.The effect of annealing on their structures and ferroelectric properties was investigated.The XRD patterns indicate th...Bi3.25La0.75Ti3O12（BLT）thin films were prepared on Pt/Ti/SiO2/Si substrate by the sol-gel method.The effect of annealing on their structures and ferroelectric properties was investigated.The XRD patterns indicate that the BLT films annealed at different temperatures are randomly orientated and the single perovskite phase is obtained at 550℃.The remmant polarization increnses and the coercive field decreases with the annealing temperature increasing.The leakage current density of the BLT films annealed at 700℃ is about 5.8×10^-8A/cm^2 at the electrie field of 250kv/cm.展开更多
We report a distinctive way for designing lead-free films with high energy storage performance.By inserting different single perovskite cells into Bi4 Ti3 O12,P-E hysteresis loops present larger maximum polarization,h...We report a distinctive way for designing lead-free films with high energy storage performance.By inserting different single perovskite cells into Bi4 Ti3 O12,P-E hysteresis loops present larger maximum polarization,higher breakdown strength and smaller slim-shaped area.We prepared 0.15 Bi7 Fe3 Ti3 O21-0.5 Bi4 Sr3 Ti6 O21-0.35 Bi4 Ba3 Ti6 O21 solid solution ferroelectric films employing the sol-gel method,and obtained high energy storage density of 132.5 J/cm3 and efficiency of 78.6%while maintaining large maximum polarization of 112.3μC/cm2 and a high breakdown electric field of 3700 kV/cm.Moreover,the energy storage density and efficiency exhibit stability over the temperature range from 20℃to 125℃,and anti-fatigue stability maintains up to 108 cycles.The films with a simple preparation method and high energy storage performance are likely to become candidates for high-performance energy storage materials.展开更多
Fatigue-free Bi3.2La0.8Ti3O12 ferroelectric thin films were successfully prepared on p-Si （100） substrates using metalorganic solution deposition process. The orientation and formation of 5-layers thin films were st...Fatigue-free Bi3.2La0.8Ti3O12 ferroelectric thin films were successfully prepared on p-Si （100） substrates using metalorganic solution deposition process. The orientation and formation of 5-layers thin films were studied under different processing conditions using XRD. Experimental results indicate that increase in annealing time at 700 ℃ after preannealing for 10 min at 400 ℃ can remarkably increase （200）-orientation of the films derived from the precursor solutions with two contents of citric acid. Meanwhile, high content of citric acid increases the film thickness and is conducive to the α-orientation of the films with the preannealing, and low concentration of the solution is conducive to the c-orientation of the films without the preannealing.展开更多
基金Project (05FJ2005) supported by the Key Project of Scientific and Technological Department of Hunan Province, China Project (05C095) supported by the Research Funds of Educational Department of Hunan Province, China
文摘Dysprosium-doped Bi4Ti3O12 (Bi3.4Dy0.6Ti3O12, BDT) ferroelectric thin films were deposited on Pt(111)/Ti/SiO2/Si(111) substrates by chemical solution deposition (CSD) and crystallized in nitrogen, air and oxygen atmospheres, respectively. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to identify the crystal structure, the surface and cross-section morphology of the deposited ferroelectric films. The results show that the crystallization atmosphere has significant effect on determining the crystallization and ferroelectric properties of the BDT films. The film crystallized in nitrogen at a relatively low temperature of 650 ℃, exhibits excellent crystallinity and ferroelectricity with a remanent polarization of 2Pr = 24.9 μC/cm2 and a coercive field of 144.5 kV/cm. While the films annealed in air and oxygen at 650 ℃ do not show good crystallinity and ferroelectricity until they are annealed at 700 ℃. The structure evolution and ferroelectric properties of BDT thin films annealed under different temperatures (600?750 ℃) were also investigated. The crystallinity of the BDT films is improved and the average grain size increases when the annealing temperature increases from 600 ℃ to 750 ℃ at an interval of 50 ℃. However, the polarization of the films is not monotonous function of the annealing temperature.
基金the Foundation of Wuhan University of Science and Technology
文摘The Bi4Ti3Oi2 and Bi3.25La0.75Ti3O12 thin films were prepared on the Pt/Ti/SiO2/Si substrate using the sol-gel method. The effect of La doping on the microstructure and ferroelectric properties of Bi4Ti3O12 films were investigated. Both the Bi4Ti3O12 and Bi3.25La0.75Ti3O12 thin films exhibited typical bismuth layered perovskite structure. The 2Pr （remanent polarization） value of Bi3.25La0.75Ti3O12 thin films is 18.6 μC/cm^2, which is much larger than that of Bi4Ti3O12 thin films. And the Bi3.2eLa0.75Ti3O12 films show fatigue-free behavior, while the Bi4Ti3O12 thin films exhibit the fatigue problem. The mechanism of improvement of La doping was discussed.
基金Funded by the International Science and Technology Cooperation Project of Hubei Province(2016AHB008)the Natural Science Foundation of Hubei Province(2015CFB724,2016CFA006)+1 种基金the National Natural Science Foundation of China(51272195,51521001)the National Key Research and Development Program of China(2017YFB0310400)
文摘Polycrystalline Bi_4Ti_3O_（12） thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt（111）/Ti/Si O_2/Si substrates by laser-ablation under different kinetic growth conditions. The relationship between the structure and ferroelectric property of the films was investigated, so as to explore the possibility of enhancing ferroelectric polarization by controlling the preferred orientation. The structural characterization indicated that the large growth rate and high oxygen background pressure were both favorable for the growth of non-c-axis oriented grains in the Bi_4Ti_3O_（12） thin films. The films with high fractions of a-axis and random orientations, i e, f（a-sxis） = 28.3% and f（random） = 69.6%, could be obtained at the deposition temperature of 973 K, oxygen partial pressure of 15 Pa and laser fluence of 4.6 J/cm^2, respectively. It was also noted that the variation of ferroelectric polarization was in accordance with the evolution non-c-axis orientation. A large value of remanent polarization（2 Pr = 35.5 μC/cm^2） was obtained for the Bi_4Ti_3O_（12） thin films with significant non-c-axis orientation, even higher than that of rare-earth-doped Bi_4Ti_3O_（12） films.
文摘Bi3.25La0.75Ti3O12（BLT）thin films were prepared on Pt/Ti/SiO2/Si substrate by the sol-gel method.The effect of annealing on their structures and ferroelectric properties was investigated.The XRD patterns indicate that the BLT films annealed at different temperatures are randomly orientated and the single perovskite phase is obtained at 550℃.The remmant polarization increnses and the coercive field decreases with the annealing temperature increasing.The leakage current density of the BLT films annealed at 700℃ is about 5.8×10^-8A/cm^2 at the electrie field of 250kv/cm.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11864028 and 12074204)。
文摘We report a distinctive way for designing lead-free films with high energy storage performance.By inserting different single perovskite cells into Bi4 Ti3 O12,P-E hysteresis loops present larger maximum polarization,higher breakdown strength and smaller slim-shaped area.We prepared 0.15 Bi7 Fe3 Ti3 O21-0.5 Bi4 Sr3 Ti6 O21-0.35 Bi4 Ba3 Ti6 O21 solid solution ferroelectric films employing the sol-gel method,and obtained high energy storage density of 132.5 J/cm3 and efficiency of 78.6%while maintaining large maximum polarization of 112.3μC/cm2 and a high breakdown electric field of 3700 kV/cm.Moreover,the energy storage density and efficiency exhibit stability over the temperature range from 20℃to 125℃,and anti-fatigue stability maintains up to 108 cycles.The films with a simple preparation method and high energy storage performance are likely to become candidates for high-performance energy storage materials.
文摘Fatigue-free Bi3.2La0.8Ti3O12 ferroelectric thin films were successfully prepared on p-Si （100） substrates using metalorganic solution deposition process. The orientation and formation of 5-layers thin films were studied under different processing conditions using XRD. Experimental results indicate that increase in annealing time at 700 ℃ after preannealing for 10 min at 400 ℃ can remarkably increase （200）-orientation of the films derived from the precursor solutions with two contents of citric acid. Meanwhile, high content of citric acid increases the film thickness and is conducive to the α-orientation of the films with the preannealing, and low concentration of the solution is conducive to the c-orientation of the films without the preannealing.
