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1.
王华  任鸣放 《物理学报》2006,55(6):3152-3156
采用Sol-Gel工艺低温制备了Si基Bi3.25La0.75Ti3O12铁电薄膜.研究了退火温度对薄膜微观结构、介电特性与铁电性能的影响.500℃退火处理的Bi3.25La0.75Ti3O12薄膜未能充分晶化,晶粒细小且有非晶团聚,介电与铁电性能均较差.高于550℃退火处理的Bi3.25La0.75 关键词: 铁电薄膜 3.25La0.75Ti3O12')" href="#">Bi3.25La0.75Ti3O12 Sol-Gel工艺  相似文献   

2.
Si基Bi4Ti3O12铁电薄膜的制备与特性研究   总被引:11,自引:6,他引:5       下载免费PDF全文
王华 《物理学报》2004,53(4):1265-1270
采用sol-gel工艺, 在分层快速退火的工艺条件下成功地制备了高质量Si基Bi4Ti3O12铁电薄膜. 研究了Si基Bi4Ti3O12薄膜的生长行为、铁电性能、C-V特性和疲劳特性. 研究表明: Si基Bi4Ti3O12薄膜具有随退火温度升高沿c轴择优生长的趋势; 退火温度通过影响薄膜的晶粒尺寸、生长取向和薄膜中载流子的浓度来改变Si基Bi关键词: sol-gel法 铁电薄膜 4Ti3O12')" href="#">Bi4Ti3O12 C-V特性  相似文献   

3.
The effects of annealing temperature on the structures, ferroelectric and magnetic properties of Aurivillius layer-structured Bi5Ti3FeO15 (BTF) films were investigated. It was found that an annealing temperature above 625 °C can lead to the appearance of Bi4Ti3O12 (BiT) secondary phase on Pt substrates. The reduction of the grain sizes was simultaneously confirmed by X-ray diffraction and atomic force microscopy with the introduction of the BiT phase. Moreover, the remanent polarization and coercive field of the BTF films were dramatically enhanced with the introduction of the BiT phase. Improved ferromagnetism for the BTF films was demonstrated upon increasing annealing temperature. Our data indicated that the ferroelectricity strongly correlated with the growth orientation of the BTF films. Finally, the possible factors for the obvious increase of the remanent polarization and coercive field, and the possible reasons for the enhanced ferromagnetic properties were discussed with increasing annealing temperature.  相似文献   

4.
Single phase and nanosized microstructure Bi4Ti3O12 thin films were prepared on fused quartz substrate by metallorganic solution deposition technique using titanium butoxide and bismuth nitrate at relatively low annealing temperature. The structural properties were characterized by XRD and AFM, which revealed that the crystallite sizes and crystallite cluster sizes of Bi4Ti3O12 were increased with the increase of the annealing temperature and about 8.65–18.3 nm by XRD study and 60–110 nm by AFM study, respectively. The refractive index and extinction coefficient of the films were calculated by Manifacier method from the spectral transmission measurement. They were increased with the increase of the annealing temperature and decreased with the increase of wavelength. The band gaps of the films were about 2.96, 2.88 and 2.80 eV for 450, 550 and 650°C annealing temperatures, respectively.  相似文献   

5.
Bi2Zn2/3Nb4/3O7 thin films were deposited on Pt/TiO2/SiO2/Si(100) substrates under an oxygen pressure of 10 Pa by pulsed laser deposition. The substrate temperature varied from 500 °C to 750 °C. Effects of substrate temperature on the crystallinity, microstructure, and electric properties of Bi2Zn2/3Nb4/3O7 thin films have been systematically investigated. Bi2Zn2/3Nb4/3O7 thin films are amorphous in nature at a substrate temperature of 500 °C. With increase of substrate temperature to 550 °C, thin films begin to crystallize. At higher temperature of 750 °C, Bi2O3 phase can be detected in thin films. However, the crystallized thin films exhibit a cubic pyrochlore structure, not a monoclinic zirconolite structure, which is probably attributed by the composition deviation from the stoichiometric ratio. The resultant Bi2Zn2/3Nb4/3O7 thin films exhibit the character with high dielectric constant and low loss tangent. The dielectric constant gradually increases with the substrate temperature and reaches a maximum at 700 °C. The dielectric constant and loss tangent of the thin films deposited at 700 °C are 152 and 0.002 at 10 kHz, respectively. With further increase of substrate temperature to 750 °C, the dielectric constant decreases to 128. However, the tunability of the resultant thin films disappears, and the temperature coefficients are positive, which implies a more ordered structure in thin films.  相似文献   

6.
Ferroelectric and dielectric properties of bilayered ferroelectric thin films, SrBi4Ti4O15 grown on Bi4Ti3O12, were investigated. The thin films were annealed at 700°C under oxygen atmosphere. The bilayered thin films were prepared on a Pt(111)/Ti/SiO2/Si substrate by a chemical solution deposition method. The dielectric constant and dielectric loss of the bilayered thin films were 645 and 0.09, respectively, at 100 kHz. The value of remnant polarization (2P r) measured from the ferroelectric thin film capacitors was 60.5 μC/cm2 at electric field of 200 kV/cm. The remnant polarization was reduced by 22% of the initial value after 1010 switching cycles. The results showed that the ferroelectric and dielectric properties of the SrBi4Ti4O15 on Bi4Ti3O12 ferroelectric thin films were better than those of the SrBi4Ti4O15 grown on a Pt-coated Si substrate suggesting that the improved properties may be due to the different nucleation and growth kinetics of SrBi4Ti4O15 on the c-axis-oriented Bi4Ti3O12 layer or on the Pt-coated Si substrate.  相似文献   

7.
(Bi,Nd)4Ti3O12 (BNT) ferroelectric films were deposited on Pt/Ti/SiO2/Si substrates by chemical solution deposition and crystallized in an N2 environment after pre-annealing in air at 500 °C. The effect of crystalline temperature on the structural and electrical properties of the BNT films was studied. The BNT films annealed in N2 in the temperature range of 630 °C to 670 °C were crystallized well and the average grain size increased with increasing crystalline temperature, while the remanent polarization and dielectric constant of the films are not a monotonic function of the crystalline temperature. The BNT films crystallized at 650 °C have the largest remanent polarization value of 2Pr=63.6 μC/cm2, a dielectric constant of 344 at 10 kHz, and a fatigue-free characteristic. A positive correlation between the remanent polarization and the dielectric constant of the BNT films has been observed. PACS 81.20.Fw; 81.40.Ef; 77.84.-s  相似文献   

8.
利用sol-gel法在Pt/Ti/SiO2/Si衬底上制备出Bi0.85Nd0.15FeO3薄膜.研究退火温度对其晶相形成的影响,发现在450 ℃退火时,Bi0.85Nd0.15FeO3晶相开始形成,但是结晶较差,而且存在杂相;在500—600 ℃退火可以获得单相Bi0.85Nd0.15FeO3薄膜,退火温度升高有利于其结晶.对600 ℃退火的Bi0.85Nd0.15FeO3薄膜的介电、铁电和电磁性能进行了测试.在测试频率为1 MHz时,其介电常数和介电损耗分别为145,0.032;饱和磁化强度大约为44.8 emu/cm3;剩余极化值(2Pr)大约是16.6 μC/cm2. 关键词: sol-gel法 0.85Nd0.15FeO3薄膜')" href="#">Bi0.85Nd0.15FeO3薄膜 铁电性能 铁磁性能  相似文献   

9.
Aurivillius-structured Bi4.15Nd0.85Ti3FeO15 multiferroic thin films with four perovskite slabs were deposited on Pt/Ti/ SiO2/Si substrates by the metal–organic decomposition method. The structural, dielectric and multiferroic properties of the films were investigated. Good ferroelectric behavior along with large dielectric constant and small loss factor were observed at room temperature. A weak ferromagnetic rather than an antiferromagnetic property was observed at room temperature by magnetic measurement. Moreover, the ferromagnetic property was enhanced when the temperature was below 13 K and a large saturation magnetization of about 5.4 emu/cm3 was obtained at 4 K. Possible reasons are put forward to discuss the complicated magnetic property.  相似文献   

10.
王华  任明放 《物理学报》2007,56(12):7315-7319
采用溶胶凝胶工艺在p-Si衬底上制备了SrBi2Ta2O9/Bi4Ti3O12复合铁电薄膜. 研究了SrBi2Ta2O9/Bi4Ti3O12复合薄膜的微观结构与生长行为、铁电性能和疲劳特性. 研究表明: Si衬底Bi4Ti< 关键词: 2Ta2O9')" href="#">SrBi2Ta2O9 4Ti3O12')" href="#">Bi4Ti3O12 复合铁电薄膜 溶胶凝胶工艺  相似文献   

11.
Nanostructured TiO2 thin films were deposited on quartz glass at room temperature by sol–gel dip coating method. The effects of annealing temperature between 200C to 1100C were investigated on the structural, morphological, and optical properties of these films. The X-ray diffraction results showed that nanostructured TiO2 thin film annealed at between 200C to 600C was amorphous transformed into the anatase phase at 700C, and further into rutile phase at 1000C. The crystallite size of TiO2 thin films was increased with increasing annealing temperature. From atomic force microscopy images it was confirmed that the microstructure of annealed thin films changed from column to nubbly. Besides, surface roughness of the thin films increases from 1.82 to 5.20 nm, and at the same time, average grain size as well grows up from about 39 to 313 nm with increase of the annealing temperature. The transmittance of the thin films annealed at 1000 and 1100C was reduced significantly in the wavelength range of about 300–700 nm due to the change of crystallite phase. Refractive index and optical high dielectric constant of the n-TiO2 thin films were increased with increasing annealing temperature, and the film thickness and the optical band gap of nanostructured TiO2 thin films were decreased.  相似文献   

12.
High-k DyScO3 linear dielectric films were considered as a buffer layer for the metal-ferroelectric-insulator-semiconductor (MFIS) structures with Aurivillius Bi3.25Nd0.75Ti3O12 ferroelectric films. The DyScO3 films on Si substrates were amorphous and dense with a smooth surface morphology, showing negligible CV hysteresis and low leakage current. The remnant polarization of ~20 μC/cm2, dielectric constant ~400, and the loss tangent ~0.04 were obtained for the ferroelectric Bi3.25Nd0.75Ti3O12 film on Pt/TiO2/SiO2/Si substrates. The Pt/Bi3.25Nd0.75Ti3O12/DyScO3/Si MFIS capacitors showed a large memory window of 4.0 V and excellent retention up to 1000 s, encouraging results for practical applications in nonvolatile RAM.  相似文献   

13.
Bismuth Zinc niobate (Bi1.5Zn1.0Nb1.5O7) thin films were deposited by pulsed laser deposition (PLD) method on fused silica substrates at different oxygen pressures. The structural, microwave dielectric and optical properties of these thin films were systematically studied for both the as-deposited and the annealed films at 600°C. The as-deposited films were all amorphous in nature but crystallized on annealing at 600°C in air. The surface morphology as studied by atomic force microscopy (AFM) reveals ultra-fine grains in the case of as-deposited thin films and cluster grain morphology on annealing. The as-deposited films exhibit refractive index in the range of 2.36–2.53 (at a wavelength of 750 nm) with an optical absorption edge value of 3.30–3.52 eV and a maximum dielectric constant of 11 at 12.15 GHz. On annealing the films at 600°C they crystallize to the cubic pyrochlore structure accompanied by an increase in band gap, refractive index and microwave dielectric constant.  相似文献   

14.
Nd-substituted bismuth titanate Bi3.54Nd0.46Ti3O12 (BNT) thin films were prepared on (111)Pt/Ti/SiO2/Si substrates by a sol–gel method. The BNT thin films processed at a low annealing temperature of ∼600 °C showed good ferroelectric properties. The randomly oriented BNT single phases and the improved ferroelectric properties were confirmed by X-ray diffraction and polarization–electric field hysteresis loops, respectively. The remanent polarization of the BNT thin films is 64 μC/cm2, which is larger than that of Bi3.25La0.75Ti3O12 (BLT) thin films. After 1010 read/write switching cycles, the effective non-volatile charges showed no polarization fatigue. Regardless of the low annealing temperature of 600 °C, the BNT thin films had good ferroelectric properties with high remanent polarizations and strong fatigue resistances. PACS 77.84.Dy  相似文献   

15.
Three Bi2Sr2Co2Oy thin films with different microstructures have been prepared by chemical solution deposition on LaAlO3(001) through varying the annealing temperature. With the decrease in the annealing temperature, both the size and c-axis alignment degree of grains in the film decrease as well, leading to an increase in the film resistivity. In addition, the decrease in the annealing temperature also results in a slight increase in the seebeck coefficient due to the enhanced energy filtering effect of small-grain film. The nanostructured Bi2Sr2Co2Oy film with the average grain size of about 100 nm shows a power factor comparable to that of the films with larger grains. Since the thermal conductivity of the nanostrcutured films can be depressed due to the enhanced phonon scattering by grain boundary, a higher figure of merit is expected in Bi2Sr2Co2Oy thin film with grains in nanometer size.  相似文献   

16.
Bi3.95Er0.05Ti3O12 (BErT) thin films were prepared on Pt/Ti/SiO2/Si and indium-tin-oxide (ITO)-coated glass substrates at room temperature by pulsed laser deposition. These thin films were amorphous with uniform thickness. Excellent dielectric characteristics have been confirmed. The amorphous BErT thin films deposited on the Pt/Ti/SiO2/Si and ITO-coated glass substrates exhibited almost the same dielectric constant of 52 with a low dielectric loss of less than 0.02 at 1 kHz. Meanwhile, the dielectric properties of the thin films had an excellent bias voltage stability and thermal stability. The amorphous BErT thin films might have potential applications in microelectronic and optoelectronic devices.  相似文献   

17.
The influence of substrate temperature on structural and dielectric properties of cubic pyrochlore Bi1.5Zn1.0Nb1.5O7 (BZN) thin films prepared by pulsed laser deposition process has been investigated. BZN thin films were deposited on Pt/Ti/SiO2/Si(1 0 0) substrate and in situ annealed at 700 °C. The results indicate that the substrate temperature has a significant effect on the structural and dielectric properties of BZN thin films. The films exhibit a cubic pyrochlore structure in the substrate temperature range from 550 °C to 700 °C and at the annealing temperature of 700 °C. With further increase of substrate temperature to 750 °C, the phases of Bi2O3, BiNbO4 and Bi5Nb3O15 can be detected in the XRD pattern due to the Zn loss. The dielectric constant and loss tangent of the films deposited at 650 °C are 192 and 6 × 10−4 at 10 kHz, respectively. The tunability is 10% at a dc bias field of 0.9 MV/cm.  相似文献   

18.
Ba0.64Sr0.36TiO3 (BST) thin films are prepared on Pt/Ti/SiO2/Si3N4/SiO2/Si substrates by a sol-gel method. Thermo-sensitive BST thin film capacitors with a Metal-Ferroelectrics-Metal (M-F(BST)-M) structure are fabricated as the active elements of dielectric type uncooled infrared sensors. XRD are employed to analyze the crystallographic structures of the films. AFM observations reveal a smooth and dense surface of the films with an average grain size of about 35 nm. Rapid temperature annealing (RTA) process is a very efficient way to improve crystallization quality. The preferable annealing temperature is 800°C for 1 min. The butterfly shaped C-V curves of the capacitors indicate the films have a ferroelectric nature. The dielectric constant and dielectric loss of the films at 100 kHz are 450 and 0.038, respectively. At 25°C, where the thermo-sensitive capacitors work, the temperature coefficient of dielectric constant (TCD) is about 5.9 %/°C. These results indicate that the capacitors with sol-gel derived BST thin films are promising to develop dielectric type uncooled infrared sensors.  相似文献   

19.
郑分刚  陈建平  李新碗 《物理学报》2006,55(6):3067-3072
选用不同浓度的Pb(Zr0.52Ti0.48)O3溶胶,用Sol-gel法在Pt/Ti/SiO2/Si基片上沉积一层厚度不同的Pb(Zr0.52Ti0.48)O3 (PZT52)过渡层,经400℃烘烤、550℃退火等程序后,再用Sol-gel法在PZT52过渡层上沉积Pb(Zr0.52Ti0.48)O 关键词: PZT铁电薄膜 择优取向 过渡层 剩余极化强度  相似文献   

20.
Ion beam sputtering process was used to deposit n-type fine-grained Bi2Te3 thin films on BK7 glass substrates at room temperature. In order to enhance the thermoelectric properties, thin films are annealed at the temperatures ranging from 100 to 400 °C. X-ray diffraction (XRD) shows that the films have preferred orientations in the c-axis direction. It is confirmed that grain growth and crystallization along the c-axis are enhanced as the annealing temperature increased. However, broad impurity peaks related to some oxygen traces increase when the annealing temperature reached 400 °C. Thermoelectric properties of Bi2Te3 thin films were investigated at room temperature. The Bi2Te3 thin films, including as-deposited, exhibit the Seebeck coefficients of −90 to −168 μV K−1 and the electrical conductivities of 3.92×102-7.20×102 S cm−1 after annealing. The Bi2Te3 film with a maximum power factor of 1.10×10−3 Wm−1 K−2 is achieved when annealed at 300 °C. As a result, both structural and transport properties have been found to be strongly affected by annealing treatment. It was considered that the annealing conditions reduce the number of potential scattering sites at grain boundaries and defects, thus improving the thermoelectric properties.  相似文献   

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