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1.
High-temperature capacitor materials sintered at 1120°C were prepared in a BaTiO3 (BT)-Na0.5Bi0.5TiO3 (NBT)-Nb2O5-ZnO-CaZrO3 system. The Curie temperature of BaTiO3 was increased by NBT doping, and a secondary phase occurred when adding ≥5 mol% NBT. The effects of Nb2O5, ZnO, and CaZrO3 on the dielectric properties and the microstructure of BT ceramics doped with 1 mol% NBT were analyzed. The overall dielectric
constant decreased when the Nb2O5 content increased, and increased when the ZnO content increased. The dielectric constant peak at the Curie temperature was
effectively depressed, and a broad secondary dielectric constant peak appeared at 60°C when the ZnO concentration was ≥4.5 mol%.
Significant grain growth was observed by scanning electron microscope (SEM) analysis as the amount of ZnO increased. The high-temperature
capacitor specification (−55°C to +175°C, ΔC/C
25°C less than ±15%) is met when 7 mol% to 8 mol% CaZrO3 is added. 相似文献
2.
N. Konofaos Zhongchun Wang S. N. Georga C. A. Krontiras M. N. Pisanias J. Sotiropoulos E. K. Evangelou 《Journal of Electronic Materials》2005,34(9):1259-1263
Highly uniform BaTiO3 (BTO) films with thickness well below 100 nm were deposited on p-Si by spin coating using a modified polymeric precursor
method. The polymeric precursor gel was redissolved into glacial acetic acid to improve the wetting property of the spinning
solution to the Si substrates (2.5-in. diameter). The morphology, composition, thickness, and refractive index of the films
were investigated using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy
(EDS), and ellipsometry. The films are found to be polycrystalline. They exhibit uniformity over the whole wafer in regard
to thickness, composition, and absence of surface features. The capacitors constructed with the BTO films on Si were further
investigated by electrical characterizations. Current-voltage (I-V) measurements reveal a leakage current due to a Poole-Frenkel
mechanism. The energy gap is evaluated to be 3.95 eV. A metal-insulator-semiconductor (MIS) behavior is observed through capacitance-conductance-voltage
(C-G-V) measurements. The interface state density (Dit) at the BTO/p-Si interface is estimated to be of the order of 1012 eV−1 cm−2. 相似文献
3.
采用固相法制备了CaTiO3掺杂的(Ba0.65Sr0.35)TiO3(BST)陶瓷,研究了CaTiO3掺杂量对BST电容器陶瓷介电性能和微观结构的影响。结果表明:随着CaTiO3掺杂量的增加,BST陶瓷的相对介电常数(εr)先增大然后减小然后增大,介质损耗(tanδ)和交流耐压强度(Eb)先增大然后减小。当CaTiO3掺杂量为摩尔分数10%时,BST陶瓷的综合介电性能较好:εr为4480,tanδ为0.022,Eb为5.8×103V/mm(AC),容温特性符合Y5U特性。 相似文献
4.
5.
High dielectric constant (high-k) polymer composites are of great interest for embedded capacitor applications. Previously,
we demonstrated that epoxy—aluminum composites are promising for embedded capacitor applications, because they have a high
dielectric constant and a low dielectric loss due to the core—shell structure of the self-passivated aluminum particles. In
this work, to further understand the dielectric behavior of aluminum composites, lower-loss polymers such as silicone, polyimide,
polynorbornene, and benzocyclobutene were explored as matrices for the aluminum composites. It is found that the polymer matrices
can significantly change the dielectric properties of the aluminum composites. A polymer matrix with a lower dielectric constant
generally results in a lower dielectric constant of its aluminum composites. In this regard, polymer—aluminum composites have
a similar dielectric characteristic as polymer—ceramic composites. Thermomechanical properties of aluminum composites were
characterized by a thermomechanical analyzer. 相似文献
6.
Two 10-mm-long multilayer prototype actuators were fabricated by a stack method using 55 pieces of 5 mm×5 mm×0.15 mm Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMNT) single crystals and PZT-5A ceramics, respectively. The strain values for PMNT multilayer piezoelectric actuators are
twice those of PZT-5A multilayer actuators, and 20.8-μm displacements can be achieved at the same E-field of 15 kV/cm. Although
thermal and electrical history markedly impact dielectric and piezoelectric performance of PMNT crystals, the PMNT multilayer
actuator can still achieve large displacements with approximately linear behavior below 60°C. Broad stable dynamic displacement
characteristic and fast displacement response make the new-type actuators promising candidates for the application in new-generation
high-performance solid-state actuators. 相似文献
7.
C. R. Becker V. Latussek G. Landwehr R. Bini L. Ulivi 《Journal of Electronic Materials》2005,34(6):811-814
The optical absorption coefficient of HgTe/Hg0.3Cd0.7Te superlattices (SLs) and its pressure dependence has been investigated at hydrostatic pressures up to 30 kbar at room temperature.
The corresponding intersubband transition energies result from a comparison of experimental and theoretical absorption coefficients.
The latter is based on the band structure, which is calculated using Kane’s four-band (8×8 k · p) model together with the
envelope function approximation. The experimental linear pressure coefficients of the H1 — E1 and H1 — L1 intersubband transitions
are in good agreement with the theoretical values, e.g., 7.15±0.3 meV/kbar and 6.2±0.3 meV/kbar compared to 7.4 and 6.4 meV/kbar,
respectively. this is in stark contrast to the pressure dependence of ≤1 meV/kbar of the photoluminescence (PL) peaks of a
similar SL reported in the literature. Consequently, we conclude that the reported PL peaks are not due to intersubband transitions
and that the k · p model correctly reproduces the electronic band structure and its pressure dependence of HgTe/Hg1−xCdxTe SLs. 相似文献
8.
从Ba(CH3COO)2-CA(NO3)2-Ti(OC4H9)-H2O-CH3COOH--CH3CH2OH体系,采用溶液.溶胶-凝胶法研究多层陶瓷电容器用(Ba1-xCAx)TiO3(x=0.05)(BCT)超细粉体的制备。利用热重差热分析仪(TG--DSC)研究BCT前驱体干凝胶加热过程中各阶段的反应历程。借助X射线衍射(XRD)、比表面积测定仪研究了热处理温度对BCT粉体的物相组成、晶粒尺寸、比表面积等的影响。得到晶相单一、颗粒尺寸在35-40nrn左右、比表面积为12.9m^2/g的BCT超细粉体。 相似文献
9.
A PbTiO3/Ba0.85Sr0.15TiO3/PbTiO3 (PT/BST15/PT) sandwich thin film has been prepared on Pt/Ti/SiO2/Si substrates by an improved sol-gel technique. It is found that such films under rapid thermal annealing at 700°C crystallize
more favorably with the addition of a PbTiO3 layer. They possess a pure, perovskite-phase structure with a random orientation. The polarization-electric field (P-E) hysteresis
loop and current-voltage (I-V) characteristic curves reveal that a PT/BST15/PT film exhibits good ferroelectricity at room
temperature. However, no sharp peak, only a weak maximum, is observed in the curves of the dielectric constant versus temperature.
The dielectric constant, loss tangent, leakage current density at 20 kV/cm, remnant polarization, and coercive field of the
PT/BST15/PT film are 438, 0.025, 1.3 × 10−6 Acm−2, 2.46 μCcm−2, and 41 kVcm−1, respectively, at 25°C and 10 kHz. The PT/BST15/PT film is a candidate material for high sensitivity elements for uncooled,
infrared, focal plane arrays (UFPAs) to be used at near ambient temperature. 相似文献
10.
11.
E. Fuentes-Fernandez W. Debray-Mechtaly M. A. Quevedo-Lopez B. Gnade A. Rajasekaran A. Hande P. Shah H. N. Alshareef 《Journal of Electronic Materials》2011,40(1):85-91
0.9Pb(Zr0.53,Ti0.47)O3-0.1Pb(Zn1/3,Nb2/3)O3 (PZT–PZN) thin films and integrated cantilevers have been fabricated. The PZT–PZN films were deposited on SiO2/Si or SiO2/Si3N4/SiO2/poly-Si/Si membranes capped with a sol–gel-derived ZrO2 buffer layer. It is found that the membrane layer stack, lead content, existence of a template layer of PbTiO3 (PT), and ramp rate during film crystallization are critical for obtaining large-grained, single-phase PZT–PZN films on the
ZrO2 surface. By controlling these parameters, the electrical properties of the PZT–PZN films, their microstructure, and phase
purity were significantly improved. PZT–PZN films with a dielectric constant of 700 to 920 were obtained, depending on the
underlying stack structure. 相似文献
12.
I. V. Bodnar 《Semiconductors》2016,50(9):1145-1150
For the single-crystal compounds In2S3 and AgIn5S8 produced by chemical gas-transport reactions and the Bridgman method (vertical version), the transmission spectra in the region of the fundamental absorption edge are studied in the temperature range from 20 to 300 K. From the recorded spectra, the band gaps of the In2S3 and AgIn5S8 single crystals are determined and the temperature dependences of the band gaps are constructed. It is established that, as the temperature is lowered, the band gap increases for both of the compounds. Calculation of the temperature dependences is performed. It is shown that the calculated and experimental values are in agreement with each other. 相似文献
13.
H. Zhang Y.J. Su L.J. Qiao W.Y. Chu D. Wang Y.X. Li 《Journal of Electronic Materials》2008,37(3):368-372
The effect of hydrogen on the fracture properties of lead-free ferroelectric ceramics has been studied. For hydrogen precharged
samples, the fracture toughness decreased linearly with both increasing hydrogen concentration and the logarithm of dwell
time of indenting. Hydrogen-induced delayed propagation of unloaded indentation cracks can occur, and the threshold stress
intensity factor of hydrogen-induced cracking induced by residual stress decreases linearly with increasing hydrogen concentration. 相似文献
14.
K.K. Allums M. Hlad A.P. Gerger B.P. Gila C.R. Abernathy S.J. Pearton F. Ren R. Dwivedi T.N. Fogarty R. Wilkins 《Journal of Electronic Materials》2007,36(4):519-523
Proton irradiation of Sc2O3/GaN and Sc2O3/MgO/GaN metal-oxide semiconductor diodes was performed at two energies, 10 MeV and 40 MeV, and total fluences of 5 × 109 cm−2, corresponding to 10 years in low-earth orbit. The proton damage causes a decrease in forward breakdown voltage and a flat-band
voltage shift in the capacitance-voltage characteristics, indicating a change in fixed oxide charge and damage to the dielectric.
The interface state densities after irradiation increased from 5.9 × 1011 cm−2 to 1.03 × 1012 cm−2 in Sc2O3/GaN diodes and from 2.33 × 1011 to 5.3 × 1011 cm−2 in Sc2O3/MgO/GaN diodes. Postannealing at 400°C in forming gas recovered most of the original characteristics but did increase the
interfacial roughness. 相似文献
15.
W. S. Tan P. A. Houston G. Hill R. J. Airey P. J. Parbook 《Journal of Electronic Materials》2004,33(5):400-407
The influence of dielectric stress on the direct current (DC) electrical characteristics of AlGaN/GaN heterostructure field-effect
transistors (HFETs) has been investigated. Dual-frequency plasma deposition was used to vary the amount of stress induced
by a passivating dielectric on the surface of the devices. Initial data suggested a strong influence from the induced dielectric
stress, but the low-frequency, radio-frequency (RF) excitation of the plasma deposition process was found to induce a severe
nonreversible damage to the exposed AlGaN surface through N ion bombardment. The consequence is a drastic reduction of the
sheet carrier concentration and mobility of the two-dimensional electron gas (2DEG). Subsequently, an alternative damage-free
technique using a helium precursor was used to obtain compressive films. Based on the results, uniform dielectric stress has
a minimal impact on the polarization charges within the AlGaN barrier. 相似文献
16.
I. V. Bodnar 《Semiconductors》2012,46(5):602-605
Single crystals of the CuIn5S8 ternary compound are grown by planar crystallization of the melt (the vertical Bridgman method). The composition and structure of the crystals are established. The specific expansion is measured by the dilatometric technique, and the coefficients of thermal expansion are calculated. From the data, the Debye temperatures (ΘD) and the root-mean-square dynamic displacements of atoms \(\left( {\sqrt {\bar u^2 } } \right)\) in the CuIn5S8 compound are calculated. From the transmittance spectra recorded in the region of the fundamental absorption edge in the temperature range 20 to 300 K, the band gap is determined and its temperature dependence is constructed. 相似文献
17.
M. Kamruzzaman Chaoping Liu A. K. M. Farid Ul Islam J. A. Zapien 《Semiconductors》2017,51(12):1615-1624
The thin film of Sb2Se3 was deposited by thermal evaporation method and the film was annealed in N2 flow in a three zone furnace at a temperature of 290°С for 30 min. The structural properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (ТЕМ), X-ray diffraction (XRD) and Raman spectroscopy, respectively. It is seen that the as-deposited film is amorphous and the annealed film is polycrystalline in nature. The surface of Sb2Se3 film is oxidized with a thickness of 1.15 nm investigated by X-ray photolecetron spectroscopy (XPS) measurement. Spectroscopic ellipsometry (SE) and UV–vis spectroscopy measurements were carried out to study the optical properties of Sb2Se3 film. In addition, the first principles calculations were applied to study the electronic and optical properties of Sb2Se3. From the theoretical calculation it is seen that Sb2Se3 is intrinsically an indirect band gap semiconductor. Importantly, the experimental band gap is in good agreement with the theoretical band gap. Furthermore, the experimental values of n, k, ε1, and ε2 are much closer to the theoretical results. However, the obtained large dielectric constants and refractive index values suggest that exciton binding energy in Sb2Se3 should be relatively small and an antireflective coating is recommended to enhance the light absorption of Sb2Se3 for thin film solar cells application. 相似文献
18.
Sridhar Govindaraju Jason M. Reifsnider Michael M. Oye Archie L. HolmesJr. 《Journal of Electronic Materials》2003,32(1):29-33
GaInNAs has received a great deal of attention among the scientific community, owing to its ability to be grown pseudomorphically
on GaAs substrates and, thus, to extend the possibility of using GaAs based materials for technologically important wavelengths
such as 1.3 μm. Annealing was found to be a very useful tool in improving the optical characteristics of as-grown GaInNAs
films. This work presents a systematic statistical analysis of two annealing parameters, time and temperature, for Ga0.8In0.2N0.01As0.99 quantum wells. Annealing, in general, has resulted in decreasing the emission wavelength by at most 0.08 μm, narrowing the
peaks by at most ∼25 meV and increasing the intensity by at most 90 times. However, from the statistical analysis, it is observed
that the temperature is the dominant factor among time and temperature in recovering the optical properties. 相似文献
19.
Chang-eun Kim Ken Kurosaki Manabu Ishimaru Hiroaki Muta Shinsuke Yamanaka 《Journal of Electronic Materials》2011,40(5):999-1004
Our group has focused attention on Ga2Te3 as a natural nanostructured thermoelectric material. Ga2Te3 has basically a zincblende structure, but one-third of the Ga sites are structural vacancies due to the valence mismatch
between Ga and Te. It has been confirmed that (1) vacancies in Ga2Te3 exist as two-dimensional (2D) vacancy planes, and (2) Ga2Te3 exhibits an unexpectedly low thermal conductivity (κ), most likely due to highly effective phonon scattering by the 2D vacancy planes. However, the effect of the size and periodicity
of the 2D vacancy planes on κ has been unclear. In addition, it has also been unclear whether only the 2D vacancy planes reduce κ or if point-type vacancies can also reduce κ. In the present study, we tried to prepare Ga2Te3 and Ga2Se3 with various vacancy distributions by controlling annealing conditions. The atomic structures of the samples were characterized
by means of transmission electron microscopy, and κ was evaluated from the thermal diffusivity measured by the laser flash method. The effects of vacancy distributions on κ of Ga2Te3 and Ga2Se3 are discussed. 相似文献
20.
Wein-Duo Yang Yen-Hwei Chang Chia-Chia Huang Yu-Chung Chen 《Journal of Electronic Materials》2009,38(3):460-467
Highly sensitive CO gas sensors based on heterocontacts of ZnO:Al on La0.8Sr0.2Co0.5Ni0.5O3 (LSCNO) were fabricated successfully. La0.8Sr0.2Co0.5Ni0.5O3 thin films were coated on (100) silicon wafers by a sol-gel method including the Pechini process followed by a spin-coating
procedure. Then, ZnO:Al films prepared by radiofrequency (RF) magnetron sputtering at various oxygen partial pressures and
deposited on as-deposited La0.8Sr0.2Co0.5Ni0.5O3 films were investigated. The results revealed that the CO sensing ability of the film prepared with the ratio of O2/Ar = 5/5 (ratio of volume flow rate) was the worst, owing to the highest (002) plane orientation in the ZnO:Al film. In contrast,
the ZnO:Al film prepared with O2/Ar = 3/7 exhibited better CO sensitivity. Furthermore, all two-layer samples showed higher CO sensitivities than single-layer
samples. The CO sensitivity of ZnO:Al/La0.8Sr0.2Co0.5Ni0.5O3 thin film was 45% for 500 ppm CO at a sensing temperature of 200°C. 相似文献