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1.
Synthesis,Ferroelectric and Optical Properties of (Pb,Ca)TiO3 Thin Films by Soft Solution Processing
Pontes F.M. Pontes D.S.L. Leite E.R. Longo E. Santos E.M.S. Mergulhão S. Varela J.A. 《Journal of Sol-Gel Science and Technology》2003,27(2):137-147
Calcium modified lead titanate sol was synthesized using a soft solution processing, the so-called polymeric precursor method. In soft chemistry method, soluble precursors such as lead acetate trihydrate, calcium carbonate and titanium isopropoxide, as starting materials, were mixed in aqueous solution. Pb0.7Ca0.3TiO3 thin films were deposited on platinum-coated silicon and quartz substrates by means of the spinning technique. The surface morphology and crystal structure, dielectric and optical properties of the thin films were investigated. The electrical measurements were conducted on metal-ferroelectric-metal (MFM) capacitors. The typical measured small signal dielectric constant and dissipation factor at a frequency of 100 kHz were 299 and 0.065, respectively, for a thin film with 230 nm thickness annealed at 600°C for 2 h. The remanent polarization (2Pr) and coercive field (E
c) were 32 C/cm2 and 100 kV/cm, respectively. Transmission spectra were recorded and from them, refractive index, extinction coefficient, and band gap energy were calculated. Thin films exhibited good optical transmissivity, and had optical direct transitions. The present study confirms the validity of the DiDomenico model for the interband transition, with a single electronic oscillator at 6.858 eV. The optical dispersion behavior of PCT thin film was found to fit well the Sellmeir dispersion equation. The band gap energy of the thin film, annealed at 600°C, was 3.56 eV. The results confirmed that soft solution processing provides an inexpensive and environmentally friendly route for the preparation of PCT thin films. 相似文献
2.
Enhanced ferroelectric,dielectric and leakage properties in Ce and Ti co-doping BiFeO3 thin films 总被引:1,自引:0,他引:1
J. Zeng Z. H. Tang M. H. Tang D. L. Xu Y. G. Xiao B. W. Zeng L. Q. Li Y. C. Zhou 《Journal of Sol-Gel Science and Technology》2014,72(3):587-592
Pure BiFeO3 (BFO), Ce and Ti individual doping and co-doping BiFeO3 thin films were fabricated via sol–gel process on Pt/Ti/SiO2/Si substrates. The microstructure, surface morphology, ferroelectric and dielectric properties of BFO and doped thin films were investigated in detail. X-ray diffraction reveal that all thin films are confirmed the formation of the distorted rhombohedral perovskite structure. No impure phase is identified in all the films. The Ce and Ti co-doping BiFeO3 (BCFTO) thin films exhibited the enhanced ferroelectricity with a large remnant polarization (2P r) of 130 μC/cm2, and low leakage current density of 9.10 × 10?6 A/cm2 which is more than two orders of magnitude lower than that of pure BFO films at 100 kV/cm. The dielectric constant (364 at 1 kHz) of the BCFTO thin films is much larger than that of pure BFO thin films. These results suggest that the introductions of Ce and Ti provides an effective route for improving the ferroelectric, dielectric and leakage properties of BFO thin films. 相似文献
3.
Zhan Jie Wang Hirokazu Usuki Toshihide Kumagai Hiroyuki Kokawa 《Journal of Sol-Gel Science and Technology》2007,42(3):375-379
(La0.7Sr0.3)MnO3 thin films were deposited on SiO2/Si substrates by a metal-organic decomposition (MOD) method, and then Pb(Zr0.52Ti0.48)O3 (PZT) thin films were grown on (La0.7Sr0.3)MnO3-coated SiO2/Si substrates by a sol-gel method. The effects of annealing temperature on the crystalline phases, microstructures and electrical
properties of the PZT films were investigated. X-ray diffraction analysis results indicated that the PZT films with a perovskite
single phase could be obtained by annealing at 650°C. The dielectric constant and the remnant polarization of the PZT films
increased with increasing annealing temperature. The remnant polarization and the coercive field of the films annealed at
650°C were 18.3 μC/cm2 and 35.5 kV/cm, respectively, whereas the dielectric constant and loss value measured at 1 kHz were approximately 1100 and
0.81, respectively. 相似文献
4.
Pb(Zr0.25Ti0.75)O3 (PZT25) thin films were prepared on LaNiO3-coated thermally oxidized silicon substrates by chemical solution deposition method, where LaNiO3 electrodes were also prepared by a chemical solution deposition technique. The dielectric constant and dielectric loss of
the PZT25 thin films were 570 and 0.057, respectively. The remanent polarization and coercive field were 20.11 μC/cm2 and 60.7 kV/cm, respectively. The PZT25 thin films on LaNiO3-coated thermally oxidized silicon substrates showed improved fatigue characteristics compared with their counterparts on
plantium-coated silicon substrates. 相似文献
5.
Wang Shimin Li Zuoyi Zhang Duanming Zhang Gangsheng Sun Junmei Zheng Ping 《Journal of Sol-Gel Science and Technology》2000,17(2):159-162
KTa0.65Nb0.35O3(KTN) thin films were prepared by sol-gel process on Pt(111)/Ti/MgO(100) substrates from KOAc, Ta(OC2H5)5 and Nb(OC2H5)5 in ethanol. The KTN thin films had a prefferred (100) orientation on Pt(111)/Ti/MgO(100) substrates and contained a small amount of pyrochlore structure phase. The 0.8-m-thick KTN film showed a room-temperature relative permittivity of 2160 and a room-temperature dielectric loss of 0.0098 at 1.0 kHz. The maximum relative permittivity of the KTN film was 4232 at 294 K and 1.0 kHz. The remanent polarization and coercive field of the KTN film were 2.8 C/cm2 and 5.0 kV/cm, respectively, at 263 K. 相似文献
6.
The thin films of mixture of xBiFeO3-(1 − x)Bi4Ti3O12 (x = 0.4, 0.5, and 0.6) system were prepared by a sol–gel process. The thicknesses of the thin films were 540, 500, and 570 nm,
respectively. The crystal structure of all thin films annealed at 650 °C was analyzed by X-ray diffraction. It was found that
the thin films at x = 0.4 and 0.5 mainly consisted of a Bi4Ti3O12 phase while Bi5Ti3FeO15 was the major phase of the thin film at x = 0.6. The thin film (x = 0.6) showed better ferroelectric properties in remnant polarization and polarization fatigue than those observed in the
thin films (x = 0.4 and 0.5). The values of remnant polarization 2P
r and coercive field 2E
c of the thin film at x = 0.6 were 36 μC/cm2 and 192 kV/cm at an applied electric field of 260 kV/cm, respectively. There was almost no polarization fatigue up to 1010 switching cycles. Also weak ferromagnetism was observed in the thin film at x = 0.6. 相似文献
7.
BaZr0.2Ti0.8O3 thin films on Pt/Ti/SiO2/Si substrates have been fabricated under low temperature conditions by a sol–gel-hydrothermal technique. The dielectric constant
is 247–83 in the frequency range of 1 kHz–1 MHz. The corresponding dielectric loss is ~10−2. The capacitance–voltage curve shows strong non-linear dielectric behavior leading to a high tunability, up to ~30% at 1 kHz.
The remanent polarization and coercive field at room temperature are measured to be ~1.5 μC/cm2 and ~90 kV/cm. The infrared optical properties of the thin films are investigated using an infrared spectroscopic ellipsometry
in the wave number range of 800–4,000 cm−1. Optical constants of the thin films are simultaneously obtained. 相似文献
8.
High performance distributed CPW phase shifters with etched BST thin films on Ф 3″ LaAlO3 substrates
Hongwei Chen Chuanren YangJihua Zhang Wei HeYu Liao Qiaozhen ZhangShanxue Zheng Guanhuan Lei 《Solid State Sciences》2012,14(1):117-120
The design, fabrication and microwave properties of distributed coplanar waveguide (CPW) phase shifters using etched Ba0.6Sr0.4TiO3 (BST) thin films on Ф 3″ LaAlO3 (100) substrates were investigated. The BST thin films employed in the circuits are deposited by RF magnetron sputtering, and then annealed at 800 °C for 30 min in air. BST thin films parallel-plate capacitors were fabricated by photolithography and etching process. At 10 kHz and 600 kV/cm electric field, the dielectric tunability, remanent polarization (2Pr) and the coercive electric field (2EC) of BST film were 28.7%, 2.265 μC/cm2 and 38.8 kV/cm, respectively. The loss tangent was 0.005 at zero electric field. The CPW phase-shifter designed was subsequently fabricated by optimum BST thin films and thickened top electrodes. At 21.3 GHz and 35 V, 360° phase shift was achieved, the insertion loss was −8.5 dB, the ?gure-of-merit (FOM) was 42.4°/dB, and the return loss was −12.1 dB. 相似文献
9.
Wataru Sakamoto Ken-ichi Mimura Takafumi Naka Tetsuo Shimura Toshinobu Yogo 《Journal of Sol-Gel Science and Technology》2007,42(3):213-220
Ba(Zr,Ti)O3/LaNiO3 layered thin films have been synthesized by chemical solution deposition (CSD) using metal-organic precursor solutions. Ba(Zr,Ti)O3 thin films with smooth surface morphology and excellent dielectric properties were prepared on Pt/TiO
x
/SiO2/Si substrates by controlling the Zr/Ti ratios in Ba(Zr,Ti)O3. Chemically derived LaNiO3 thin films crystallized into the perovskite single phase and their conductivity was sufficiently high as a thin-film electrode.
Ba(Zr,Ti)O3/LaNiO3 layered thin films of single phase perovskite were fabricated on SiO2/Si and fused silica substrates. The dielectric constant of a Ba(Zr0.2Ti0.8)O3 thin film prepared at 700°C on a LaNiO3/fused silica substrate was found to be approximately 830 with a dielectric loss of 5% at 1 kHz and room temperature. Although
the Ba(Zr0.2Ti0.8)O3 thin film on the LaNiO3/fused silica substrate showed a smaller dielectric constant than the Ba(Zr0.2Ti0.8)O3 thin film on Pt/TiO
x
/SiO2/Si, small temperature dependence of dielectric constant was achieved over a wide temperature range. Furthermore, the fabrication
of the Ba(Zr,Ti)O3/LaNiO3 films in alternate thin layers similar to a multilayer capacitor structure was performed by the same solution deposition
process. 相似文献
10.
Lili Chen Mingrong Shen Liang Fang Yu Xu 《Journal of Sol-Gel Science and Technology》2007,42(3):299-303
A TiO2 thin buffer layer was introduced between the (Pb0.4Sr0.6)TiO3 (PST) film and the Pt/Ti/SiO2/Si substrate in an attempt to improve their electrical properties. Both TiO2 and PST layers were prepared by a chemical solution deposition method. It was found that the TiO2 buffer layer increased the (100)/(001) preferred orientation of PST and decreased the surface roughness of the films, leading
to an enhancement in electrical properties including an increase in dielectric constant and in its tunability by DC voltage,
as well as a decrease in dielectric loss and leakage current density. At an optimized thickness of the TiO2 buffer layer deposited using 0.02 mol/l TiO2 sol, the 330-nm-thick PST films had a dielectric constant, loss and tunability of 1126, 0.044 and 60.7% at 10 kHz, respectively,
while the leakage current density was 1.95 × 10−6 A/cm2 at 100 kV/cm. 相似文献
11.
Carine Livage Ahmad Safari Lisa C. Klein 《Journal of Sol-Gel Science and Technology》1994,2(1-3):605-609
A new sol-gel system using ethylene glycol was developed for the fabrication of PZT thin films with compositions near the morphotropic phase boundary Pb(Zr0.52Ti0.48)O3. Ethylene glycol was used as both a chelating agent and a solvent to replace the highly toxic methoxyethanol used in previous formulations. Thin films were deposited by spin coating the solutions onto platinized silicon substrates. Films were completely crystallized by about 600°C and contained the ferroelectric perovskite phase. A dielectric constant of about 750–800 at 1 KHz was obtained for thin films of 0.3 µm thickness. The hysteresis measurements revealed a remanent polarization of 15 mC/cm2 with a coercive field of 60 kV/cm. 相似文献
12.
Paik Dong Soo Rao A.V. Prasada Komarneni S. 《Journal of Sol-Gel Science and Technology》1997,10(2):213-220
Randomly oriented ferroelectric BaTiO3 and (Ba0.6Sr0.4) TiO3 thin films on platinum coated Si (100) were prepared by a sol-gel method. The precursor solutions were derived from barium hydroxide or a mixture of barium/strontium hydroxides dissolved in acetic acid and titanium butoxide. Polarization versus applied voltage hysteresis studies indicated a remanent polarization of 3 µC/cm2 and a coercive field of 43.4 kV/cm for BaTiO3 films annealed at 800°C for 1 h. Corresponding parameters for (Ba0.6Sr0.4)TiO3 films annealed at 800°C were found to be 7.2 µC/cm2 and 102.7 kV/cm, respectively. Microstructural study of the surface morphology of these films indicated grains of less than 0.1 µm in size. The leakage current for (Ba0.6Sr0.4)TiO3 films was found to be two orders of magnitude lower than that for BaTiO3 films. 相似文献
13.
Chuanqing Li Aiyun Liu Junqiang Shi Yafei Ruan Lei Huang Wangzhou Shi Xiangjian Meng Jinglan Sun Junhao Chu Xiaodong Zhang 《Journal of Sol-Gel Science and Technology》2011,60(2):164-169
80%Pb(Zn1/3Nb2/3)O3–20%PbTiO3 (PZN–PT) thin films have been prepared on Pt/Ti/SiO2/Si substrates using a modified sol–gel method. In our method, niobium pentaoxide is used as a substitution instead of niobium
ethoxide which is moisture-sensitivity and much more expensive. Microstructure and electrical properties of PZN–PT thin films
have been investigated. X-ray diffraction analysis shows that proper annealing temperature of PZN–PT thin films is 600 °C.
The PZN–PT thin films annealed at 600 °C are polycrystalline with (111)-preferential orientations. Field-emissiom scanning
electron microscope analysis revealed PZN–PT thin films possess well-defined and crack-free microstructure. The thickness
of thin films is 290 nm. The Pt/PZN–PT/Pt capacitors have been fabricated and it presents ferroelectric nature. The remanent
polarization (Pr), spontaneous polarization (Ps), and the coercive electric field (Ec) are 8.71 μC/cm2, 43.06 μC/cm2, and 109 kV/cm at 1 MHz, respectively. The dielectric constant (εr) and the dissipation factor (tan δ) are about 500.3 and 0.1 at 1 kHz, respectively. 相似文献
14.
Ling Pei Ni Hu Gang Deng Yiwan Chen Yeguang Bie Meiya Li Xiaolian Liu 《Journal of Sol-Gel Science and Technology》2012,64(3):711-717
The effects of Tb substitution on the structural and electrical properties of ferroelectric Bi4Ti3O12 (BTO) thin films grown on Pt/TiO2/SiO2/Si substrates by a sol–gel process have been reported. X-ray diffraction indicated A-site Tb substitutions did not change the polycrystalline bi-layered Aurivillius structure of the BTO, but a lattice distortion was observed. The leakage current behavior at room temperature of the films was studied and it was found that the leakage current density decreased from 10?2 to 10?4 A/cm2 with the increase of x under 150 kV/cm. The remnant polarization (2P r ) and dielectric constant (ε r) increase firstly and then decreases with the increase of the Tb content. We observed a substantial increase in the remnant polarization (2P r ) with Tb substitution and obtained a maximum value of~60 μC/cm2 at an applied electric field of 500 kV/cm for x = 0.4. Moreover, this BTT-0.4 capacitor did not show fatigue behaviors after 1.0 × 1010 switching cycles, suggesting an anti-fatigue character. 相似文献
15.
T. Tsuchiya T. Sei Y. Watanabe M. Mori T. Kineri 《Journal of Sol-Gel Science and Technology》1997,8(1-3):685-688
Gold-dispersed BaTiO3, PGO and PLT thin films, which will be used for third-order nonlinear optical devices, were prepared by sol-gel process with
spin-coating using HAuCl44H2O, Ba(CH3COO)2, Ti[O(CH2)3CH3]4, Pb(CH3COO)23H2O, Ge[O-n-C4H9]4, La(CH3COO)31.5 H2O as starting materials. The thin films were heat-treated in air at temperatures ranging from 400 to 800 for 1 h. The nonlinear
optical property of these thin films was measured by the degenerate four-wave mixing (DFWM) method using a frequency-doubled
Nd: YAG laser with 20 ps pulse duration. Third-order nonlinear susceptibility χ(3) of gold-dispersed BaTiO3, PGO and PLT thin films with 5 vol% of gold were 1.410−6 esu, 3.510−7 esu respectively. The large χ(3) may be ascribed to the high dielectric constant of the films. 相似文献
16.
Toyoda Masahiro Lubis Muhamm Yusuf Sahriza 《Journal of Sol-Gel Science and Technology》1999,16(1-2):7-12
(Ba0.92,Ca0.08)(Ti0.92,Zr0.08)O3 thin films were prepared from Ba-Ti and Ca-Zr precursors by sol-gel processing. Polymerizable solutions containing Ba-Ti and Ca-Zr, respectively, were newly synthesized. Decomposition of the starting compounds and crystallization behavior of the film were examined by using TG/DTA and XRD. Microstructure of thin films was observed by using SEM. Polycrystalline (Ba0.92,Ca0.08)(Ti0.92, Zr0.08)O3 films obtained by firing at 800°C were dense with fine grains. The thin films showed a dielectric constant of 1200 and dielectric loss of 0.5%. 相似文献
17.
Ce-substituted BiFeO3 film (BCFO film) have been prepared by sol–gel process on F doped SnO2 (FTO)/glass substrates. The effects of Ce substitution on the structural and electrical properties have been reported. X-ray
diffraction data confirmed the R3c structure with the elimination of all secondary phases. We observed an increase in the
remnant polarization (Pr) with Ce substitution and obtained a maximum value of ∼84 μC/cm2 in 5% Ce-substituted film. The dielectric constant of the films was increased from 280 to about 420 for the BiFeO3 film and 5% Ce-substituted BCFO film, respectively and the films showed excellent dielectric loss behavior. Moreover, the
leakage current was substantially reduced by the Ce substitution. 相似文献
18.
The third-order nonlinear optical properties of the sol-gel derived Pb(Fe1/2Nb1/2)O3-PbTiO3 (PFN-PT) thin films have been investigated by the THG method. The χ(3) values of PFN-PT thin films increased from 3.2×10−12 esu (PT) to 8.5×10−12 esu (PFN) with increasing content of Fe3+ ions which possessed very high second-hyperpolarizability, ψ(Fe2/3O). It was experimentally confirmed that complex oxides such as ABO3-type perovskites consisting of large non-transition metal A-site cations and small transition metal B-site cations exhibited
high χ(3) as expected from Lines' model. It was also found that the χ(3) values of complex oxides could be estimated from the second-hyperpolarizabilities of the constituent single oxides reported
so far. Because of the large remanent polarization, PT thin films may exhibit the highest χ(3) among the ferroelectric PFN-PT thin films studied in the present work. The maximum dielectric constant, ε, of 1990 at room
temperature was obtained for 0.5PFN·0.5PT thin films, whose composition corresponds to so-called morphotropic phase boundary
(MPB). 相似文献
19.
Xiujian Chou Maoxiang Guo Yating Zhang Jun Liu Wendong Zhang 《Journal of Sol-Gel Science and Technology》2012,61(1):62-68
Pb0.97La0.02Zr0.95Ti0.05O3 (PLZT) antiferroelectric thick films of highly preferred-(100) orientation with different thickness were successfully deposited
on Pt(111)/Ti/SiO2/Si(100) substrates depending on the sol–gel process technique. The effects of the PLZT thick films in the preparation and
electric properties are investigated. The films show polycrystalline perovskite structure with a (100) preferred orientation
by X-ray diffractometer analyses. The antiferroelectric nature of the thick films is demonstrated by P (polarization)–E (electric
field). The temperature dependence of the dielectric constant and dielectric loss displays the similar behavior in both cases
at 100 kHz while the values of polarization characteristic are decreased with the increase of the film thickness. The phase
switching current are studied as a function of a gradually change dc electric field and the voltage dependent current density
of the most highly (100)-oriented PLZT film is 1.49 × 10−8 A/cm2 over electric field range from 0 to ±261 kV/cm. The film at 2,498 nm exhibits excellent dielectric properties and highly
preferred-(100) orientation. 相似文献
20.
Dan Xie Zhigang Zhang Tianling Ren Litian Liu 《Journal of Sol-Gel Science and Technology》2007,42(3):271-276
Bi-layered ferroelectric Bi3TiTaO9 (BTT) thin films with different thickness (ranging from 100 to 400 nm) were successfully fabricated on Pt(111)/TiO2/SiO2/(100)Si substrates using chemical solution deposition (CSD) technique at different annealing temperatures. The c-axis orientation of the films was affected by film thickness and process temperature. The thinner the film and the higher
the process temperature, the higher the c-axis orientation. With the increase of film thickness, the stress decreased but the film roughness increased, which led to
the decrease of c-axis orientation of films. BTT films annealed at 800°C were found to have much improved remament polarization (P
r
) than that of films annealed at 650 and 750°C. The P
r
and coercive field (E
c
) values were measured to be 2 μC/cm2 and 100 kV/cm, respectively. BTT films showed well-defined ferroelectric properties with grain size larger than 100 nm. 相似文献