scholarly journals Dielectric tunable characteristics of compositional-gradient BaTi1−xSnxO3 thin films

2021 ◽  
Vol 11 (04) ◽  
pp. 2150019
Author(s):  
Chenjing Wu ◽  
Manwen Yao

Compositional-gradient [Formula: see text][Formula: see text]O3 thin films on Pt(100)/Ti/SiO2/Si substrates are fabricated with sol–gel using spin coating. All of the structures of the prepared thin films are of single-phase crystalline perovskite with a dense and crack-free surface morphology. BTS10/15/20 thin film exhibits enhanced temperature stability in its dielectric behavior. The temperature coefficient of capacitance [Formula: see text] in the temperature range from [Formula: see text]C to [Formula: see text]C is [Formula: see text]C and that of [Formula: see text] in the temperature range from [Formula: see text]C to [Formula: see text]C is [Formula: see text]C. Furthermore, the thin films show low leakage current density and dielectric loss. High and stable dielectric tunable performances are found in BTS10/15/20 thin films: the dielectric tunability of the thin films is around 20.1% under a bias voltage of 8 V at 1 MHz and the corresponding dielectric constant is in the range between 89 and 111, which is beneficial for impedance matching in circuits. Dielectric tunability can be obtained under a low tuning voltage, which helps ensure safety. The simulated resonant frequency of the compositional-gradient BTS thin films depends on the bias electric field, showing compositional-gradient BTS thin films could be used in electrically tunable components and devices. These properties make compositional-gradient BTS thin films a promising candidate for dielectric tuning.

2001 ◽  
Vol 672 ◽  
Author(s):  
S. Bhaskar ◽  
S. B. Majumder ◽  
P. S. Dobal ◽  
S. B. Krupanidhi ◽  
R. S. Katiyar

ABSTRACTSol-Gel derived Pb0.85La0.15TiO3 PLT15) thin films were deposited on solution derived RuO2/Si, RuO2/Pt/Si and Pt bottom electrodes. Dielectric, tangent loss, hysteresis, J-E, measurements were also carried out on these films. X-ray results established the single phase perovskite formation with no secondary phases of PLT15 thin film on these electrodes. PLT15 thin films on RuO2 bottom electrode showed relatively inferior ferroelectric and dielectric behavior as compared to Pt electrode. Low leakage currents (10-8 A/cm2 at 10 kV/cm) and the observed J-E characteristics have been attributed to poor film-electrode interface. Observed electrical and dielectric properties have been correlated with the film-electrode interface. The interface characteristics were further augmented by depth profile analysis using Auger Electron Spectroscopy.


2001 ◽  
Vol 688 ◽  
Author(s):  
S. Bhaskar ◽  
S. B. Majumder ◽  
R. S. Katiyar

AbstractTemperature dependent dielectric behavior of sol-gel derived ferroelectric Pb1−xLaxTiO3 (PLT) (x = 0.05 to 0.30) thin films on Pt/Si substrates has been studied. The characteristics of the diffuse phase transition and possible relaxor behavior of PbTiO3 thin films doped with different amounts of La are investigated. Room temperature X-ray and micro Raman results indicate that the crystal structure of the PLT films was strongly influenced by the La content. The softening of the E(1TO) mode with increasing La content indicates that the incorporation of La in the PT lattice results in a structural disorder in the material. The dielectric permittivity and loss tangent of the PLT thin films were measured in the temperature range of 80 –700 K at frequencies between 1 kHz and 1 MHz. Transition temperatures (Tm) for PLT (x = 0.05, 0.20, and 0.30) are 640, 460, and 254 K respectively, and are higher in comparison to reported values of bulk ceramics. The permittivity maximum broadened, and showed relaxor- type frequency dependent permittivity characteristics for PLT (x = 0.30) films. The broadening parameter was significantly influenced by La doping and our results indicate that PLT thin films undergo a normal-to-relaxor ferroelectric transformation for La concentrations of 25 at% in PLT films.


2021 ◽  
Author(s):  
Yi Ye ◽  
Fengzhen Huang ◽  
Lin Lei ◽  
Lin Liu ◽  
Shuo Yan ◽  
...  

Abstract Electrocaloric effect (ECE) driven by electric field is suitable for implementation of built-in cooling in electronic devices. However, most of the known electrocaloric materials show low adiabatic temperature change ( ) near room temperature and usually require high electric field. Here, the investigation of ECE in Pb 1+x ZrO 3 (x=0, 0.1, 0.15) thin films, which were prepared on Pt/Ti/SiO 2 /Si substrates by sol-gel method, reveals that both the magnitude and the present temperature range of can be controlled by Pb concentration. Through increasing the dosage of PbO, decreased lead vacancies and enhanced interface layer are induced, which postpone the transition from antiferroelectrics to ferroelectrics of PbZrO 3 films under a given electric field ( E ), which thus controls the appearance temperature range of negative ECE. As a result, large isothermal entropy change ( and are observed in the temperature range from 260 K to 494 K, depending on the applied electric field and Pb concentration. Giant ECE ( , ~0.054) at room temperature (303 K) is obtained in Pb 1.1 ZrO 3 films under 460 kV/cm. This result provides a convenient method for modulating ECE of PbZrO 3 -based materials and will benefit its applications in cooling devices.


2007 ◽  
Vol 336-338 ◽  
pp. 21-23
Author(s):  
Qiu Sun ◽  
Ying Song ◽  
Fu Ping Wang

The Pb(Zr0.52Ti0.48)O3 thin films with 0-2at.%Gd dopants (denoted as PGZT) were prepared on Pt/Ti/SiO2/Si substrates by a sol-gel technique and a rapid thermal annealing process. The structures of PGZT films were characterized and the ferroelectric properties such as P–V loop, C–V and I–V characteristics were investigated. Improved polarization (2Pr = 46.373 μC/cm2) and the low leakage current (J = 1.5×10-9 A/cm2 at the electric field of 400 kV/cm) were obtained in the PZT thin film with 1at.% Gd dopant, which was better than that of the pure PZT thin film (2Pr = 39.099 μC/cm2, J = 4.3×10-8A/cm2). With the Gd contents up to 2at.%, a decreased remanent polarization was found.


2015 ◽  
Vol 3 (9) ◽  
pp. 2115-2122 ◽  
Author(s):  
Wei Sun ◽  
Jing-Feng Li ◽  
Qi Yu ◽  
Li-Qian Cheng

We prepared high-quality Bi1−xSmxFeO3 films on Pt(111)/Ti/SiO2/Si substrates by sol–gel processing and found rhombohedral–orthorhombic phase transition with enhanced piezoelectricity.


2011 ◽  
Vol 197-198 ◽  
pp. 1781-1784
Author(s):  
Hua Wang ◽  
Jian Li ◽  
Ji Wen Xu ◽  
Ling Yang ◽  
Shang Ju Zhou

Intergrowth-superlattice-structured SrBi4Ti4O15–Bi4Ti3O12(SBT–BIT) films prepared on p-Si substrates by sol-gel processing. Synthesized SBT–BIT films exhibit good ferroelectric properties. As the annealing temperature increases from 600°C to 700°C, the remanent polarization Prof SBT–BIT films increases, while the coercive electric field Ecdecreases. SBT–BIT films annealed at 700°C have a Prvalue of 18.9µC/cm2which is higher than that of SBT (16.8µC/cm2) and BIT (14.6µC/cm2), and have the lowest Ecof 142 kV/cm which is almost the same as that of SBT and BIT. The C-V curves of Ag/SBT-BIT/p-Si heterostructures show the clockwise hysteresis loops which reveal the memory effect due to the polarization. The memory window in C-V curve of Ag/SBT-BIT/p-Si is larger than that of Ag/SBT/p-Si heterostructure or Ag/BIT/p-Si heterostructure.


2010 ◽  
Vol 663-665 ◽  
pp. 650-653
Author(s):  
Jin Moo Byun ◽  
Jeong Sun Han ◽  
Jae Hyoung Park ◽  
Seong Eui Lee ◽  
Hee Chul Lee

This study examined the effect of crystalline orientation and dopants such as Nb and Zn on the piezoelectric coefficient of sol-gel driven Pb1(Zr0.52Ti0.48)O3(PZT) and doped PZT thin films. Crack-free 1-μm-thick PZT and doped PZT thin films prepared by using 2-Methoxyethanol-based sol-gel method were fabricated on Pt/Ti/SiO2/Si substrates. The highly (111) oriented PZT thin films of pure perovskite structure could be obtained by controlling various parameters such as a PbTiO3 seed layer and a concentration of sol-gel solution. The Nb-Zn doped PZT thin films exhibited high piezoelectric coefficient which was about 50 % higher than that of undoped PZT thin film. The highest measured piezoelectric coefficient was 240 pC/N, which could be applicable to piezoelectrically operated MEMS actuator, sensor, or energy harvester devices.


1996 ◽  
Vol 433 ◽  
Author(s):  
T. B. Wu ◽  
J. M. Wu ◽  
C. M. Wu ◽  
M. J. Shyu ◽  
M. S. Chen ◽  
...  

AbstractHighly (100)-textured thin film of metallic LaNiO3 (LNO) was grown on the Pt/Ti/SiO2/Si substrates by rf magnetron sputtering at ˜300°C, which was used as a bottom electrode to prepare highly (100)-textured ferroelectric films. Examples on the deposition of PbTiO3, (Pbl−xLax)TiO3, Pb(Zr0.53Ti0.47)O3, Pb[(Mg1/3Nb2/3)1−xTix]O3, and (Ba1−xSrx)TiO3 thin films by rf magnetron sputtering or sol-gel method are shown. A reduction of temperature for perovskite phase formation can be achieved, especially for those difficult to crystallize. The surface roughness of the ferroelectric films is also improved as compared to that of films deposited on conventional Pt electrode. Although the electrical properties of the ferroelectric films are affected by the out-diffusion of LNO when a higher temperature was used in the preparation of the films, under an appropriate processing condition, the highly (100)-textured films can have satisfactory electrical characteristics for application. Moreover, the polarization-fatigue property can be also improved by the use of LNO electrode.


2003 ◽  
Vol 784 ◽  
Author(s):  
Se-Yeon Jung ◽  
Woo-Chul Kwak ◽  
Seung-Joon Hwang ◽  
Yun-Mo Sung

ABSTRACTSr0.7Bi2.4Ta2O9 (SBT) thin films were deposited on Pt/Ti/SiO2/Si substrates with and without a seed layer of ∼40 nm thickness using sol-gel and spin coating methods. The influence of seed layer on the phase formation characteristics of SBT thin films was investigated using x-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. Formation of pyrochlore as well as Aurivillius phase was observed in both the unseeded and seeded SBT films heated at 740°C. However, it was revealed that Aurivillius phase formation was enhanced in seeded SBT thin films and pyrochlore phase formation was highly suppressed. In this study, two possible mechanisms for the suppression of pyrochlore phase formation were proposed from the perspectives of activation energy difference for Aurivillius and pyrochlore phase formation and Bi-ion diffusion to pyrochlore phase.


2014 ◽  
Vol 703 ◽  
pp. 51-55
Author(s):  
Jia Zeng ◽  
Ming Hua Tang ◽  
Zhen Hua Tang ◽  
Yong Guang Xiao ◽  
Long Peng ◽  
...  

Bi0.94Ce0.06Fe0.97Ti0.03O3 and Bi0.94Ce0.06Fe0.97Ti0.03O3/Bi3.15Nd0.85Ti3O12 double-layered thin films were fabricated via sol-gel process on Pt/Ti/SiO2/Si substrates. The influence of Bi3.15Nd0.85Ti3O12 buffer layer on microstructure and electrical properties of Bi0.94Ce0.06Fe0.97Ti0.03O3 thin films were investigated in detail. Well-saturated P-E hysteresis loops can be obtained in Bi0.94Ce0.06Fe0.97Ti0.03O3 films with Bi3.15Nd0.85Ti3O12 buffer. The remnant polarization (2Pr) of the double-layered thin films is 112 μC/cm2. The coercive field (2Ec) of double-layered films is 672 kV/cm, which is much lower than that of the Bi0.94Ce0.06Fe0.97Ti0.03O3 thin films. The leakage current density of Bi0.94Ce0.06Fe0.97Ti0.03O3/Bi3.15Nd0.85Ti3O12 double-layered thin films is 4.12×10-5 A/cm2.


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