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1.
(Ba,Co,Nb)掺杂SnO2压敏材料电学非线性的研究 总被引:2,自引:0,他引:2
通过对样品的伏安特性,晶界势垒的测量和分析,研究了BaCO3对新型(Co,Nb)掺杂SnO2压敏材料微观结构和电学性质的影响。晶界势垒高度测量表明,SnO2晶粒尺寸的迅速减小是压敏电压急剧增高的原因。对Ba含量增加引起SnO2晶粒减小的根源进行了解释。掺杂x(BaCO3)=0.4%的SnO2压敏电阻击穿电压为最小(140V/mm);掺杂x(BaCO3)-0.8%的SnO2压敏电阻具有最高非线性系数(α=19.6),最高的势垒电压(ψB=1.28eV)。 相似文献
2.
Zr掺杂的SnO_2瓷的压敏和介电性质 总被引:4,自引:1,他引:3
目前电子陶瓷工艺普遍采用ZrO2球作为磨介。为了弄清ZrO2球磨损对压敏瓷性能的作用,系统研究了ZrO2对(Co,Nb)掺杂SnO2瓷的压敏和介电性质的影响。当ZrO2的含量(摩尔分数)从0.00增加到1.00%时,(Co,Nb)掺杂的SnO2压敏电阻的击穿电压从345 V/mm增大到485 V/mm,1 kHz时的相对介电常数从1 590减小到1 120。晶界势垒高度测量表明:在实验范围内,Zr的含量对势垒高度的影响较小。SnO2的晶粒尺寸的迅速减小是击穿电压增高和介电常数迅速减小的主要原因。对Zr掺杂量增加引起SnO2晶粒减小的根源进行了解释。 相似文献
3.
Nb掺杂对ZnO压敏陶瓷电学性能的影响 总被引:2,自引:0,他引:2
研究了Nb2O5对ZnO压敏材料电学性能的影响。当x(Nb2O5)从0增加到1%时,ZnO压敏电阻的击穿电压从209V/mm降至0.70V/mm,40Hz时,样品电阻从0.21MΩ降至48.3Ω,1kHz时的相对介电常数从831增大到42200。晶界势垒高度测量表明:在实验范围内,Nb对势垒高度的影响较小。ZnO晶粒的变大是压敏电压急剧降低和介电常数增大的主要原因。对Nb掺杂量的增加引起样品阻抗减小的根源进行了解释。 相似文献
4.
CeO_2掺杂引起SnO_2压敏电阻的晶粒尺寸效应 总被引:4,自引:2,他引:2
研究了掺CeO2对SnO2Co2O3Ta2O5压敏电阻器性能的影响。研究发现:随着x(CeO2)从0增加到1%,压敏电压从190 V/mm增加到205 V/mm,相对介电常数从3 317减小到2 243,晶粒平均尺寸从12.16 mm减小到6.23 mm,在晶界上的Ce4+阻碍了SnO2晶粒的生长。为了解释样品电学非线性性质的起源,笔者提出了SnO2Co2O3Ta2O5CeO2晶界缺陷势垒模型。同时,对该压敏电阻器进行了等效电路分析,试验测量与等效电路分析结果相符。 相似文献
5.
对 Si O2 掺杂的 Sn O2 · Co O· Nb2 O5 压敏电阻非线性电学性质进行了研究 ,并对其微观结构进行了电镜扫描 ,且对其晶界势垒高度进行了测量。实验表明 x(Si O2 ) =0 .3%掺杂的 Sn O2 · Co O· Nb2 O5 压敏电阻的非线性系数 α高达 30 ,并且具有最高的击穿电场 (375 V/ mm)。采用 Gupta- Carlson缺陷模型对晶界肖特基势垒高度随Si O2 的添加而变大的现象进行了理论解释。 相似文献
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研究了TiO2掺杂对SnO2-Co2O3-Nb2O5系压敏陶瓷材料电学性能的影响。掺入x(TiO2)为1.00%的陶瓷样品具有最高的密度(r = 6.82 g/cm3),最高的视在势垒电场(EB= 476 V/mm),最高的非线性系数(a = 11.0),最小的相对介电常数。未掺杂的样品阻抗最大。随TiO2掺杂量的增加晶粒逐渐变小,晶粒尺寸的减小归因于未固溶于SnO2晶格而偏析在晶界上的TiO2阻碍相邻SnO2晶粒融合。为了解释SnO2-Co2O3-Nb2O5-TiO2系电学非线性性质的根源,对前人的晶界缺陷势垒模型进行了修正。 相似文献
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Metal Oxide Transistors via Polyethylenimine Doping of the Channel Layer: Interplay of Doping,Microstructure, and Charge Transport 下载免费PDF全文
Wei Huang Li Zeng Xinge Yu Peijun Guo Binghao Wang Qing Ma Robert P. H. Chang Junsheng Yu Michael J. Bedzyk Tobin J. Marks Antonio Facchetti 《Advanced functional materials》2016,26(34):6179-6187
Polymer doping of solution‐processed In2O3 with small amounts of the electron‐rich polymer, polyethylenimine (PEI), affords superior transistor performance, including higher electron mobility than that of the pristine In2O3 matrix. PEI doping of In2O3 films not only frustrates crystallization and controls the carrier concentration but, more importantly, acts as electron dopant and/or scattering center depending on the polymer doping concentration. The electron donating capacity of PEI combined with charge trapping and variation in the matrix film microstructure yields, for optimum PEI doping concentrations of 1.0%–1.5%, electron mobilities as high as ≈9 cm2 V?1 s?1 on a 300 nm SiO2 gate dielectric, an excellent on/off ratio of ≈107, and an application optimal V T. Importantly, these metrics exceed those of the pure In2O3 matrix with a maximum mobility ≈4 cm2 V?1 s?1. Furthermore, we show that this approach is extendible to other oxide compositions such as IZO and the technologically relevant IGZO. This work opens a new means to fabricate amorphous semiconductors via solution processing at low temperatures, while preserving or enhancing the mobility of the pristine polycrystalline semiconductor. 相似文献
12.
Oxide Transistors: Metal Oxide Transistors via Polyethylenimine Doping of the Channel Layer: Interplay of Doping,Microstructure, and Charge Transport (Adv. Funct. Mater. 34/2016) 下载免费PDF全文
Wei Huang Li Zeng Xinge Yu Peijun Guo Binghao Wang Qing Ma Robert P. H. Chang Junsheng Yu Michael J. Bedzyk Tobin J. Marks Antonio Facchetti 《Advanced functional materials》2016,26(34):6320-6320
13.
In this paper, we have exposed the effects of molarity on structural, optical, morphological and gas sensing properties of copper oxide films deposited by pneumatic spray pyrolysis method. The molar concentration was varied from 0.05 to 0.3 M. X-ray diffractograms showed the formation of a single phase CuO for films prepared with 0.05 and 0.1 M concentrations. A secondary phase Cu2O was obtained for 0.2 and 0.3 M concentrations. Optical measurements showed that 0.05 M concentration provides a film with the best transparency in the visible and near infrared regions. The thickness values were between 2 and 110 µm. Moreover, the contact angle measurements have shown that all the deposited films are hydrophobic with angles between 103° and 121°. The morphological properties were investigated using SEM and AFM. According to SEM and AFM micrographs, 0.05 M is the concentration that leads to porous structure. The gas sensing measurements confirm that this porous surface structure is the most sensitive to different CO2 concentrations. 相似文献
14.
C. K. Williams 《Journal of Electronic Materials》1992,21(7):711-720
The trapping and detrapping of charge in the oxides have been studied for two decades. While there has been a lot of progress
in understanding the mechanisms responsible for charge trapping and detrapping in these oxides, it is still not fully understood.
For example, even under low field injection conditions first order trapping kinetics do not accurately model the observed
data. Under high field injection the situation is exacerbated by the generation of additional trapping sites during the injection
process, which is also not completely understood. The paper presents a review of the kinetics of trapping and detrapping and
describes various models that have been proposed to explain experimentally observed trapping-detrapping behavior. 相似文献
15.
Li Zhao Tokuhiro Chano Shigehiro Morikawa Yukie Saito Akihiko Shiino Sawako Shimizu Takuro Maeda Takayoshi Irie Shuji Aonuma Hidetoshi Okabe Takahide Kimura Toshiro Inubushi Naoki Komatsu 《Advanced functional materials》2012,22(24):5107-5117
For biomedical application of nanoparticles, the surface chemical functionality is very important to impart additional functions, such as solubility and stability in a physiological environment, and targeting specificity as an imaging probe and a drug carrier. Although polyethylene glycol (PEG) has been used extensively, here, it is proposed that hyperbranched polyglycerol (PG) is a good or even better alternative to PEG. Superparamagnetic iron oxide nanoparticles (SPIONs) prepared using a polyol method are directly functionalized with PG through ring‐opening polymerization of glycidol. The resulting SPION‐PG is highly soluble in pure water (>40 mg mL?1) and in a phosphate buffer solution (>25 mg mL?1). Such high solubility enables separation of SPION‐PG according to size using size exclusion chromatography (SEC). The size‐separated SPION‐PG shows a gradual increase in transverse relaxivity (r2) with increasing particle size. For biological application, SPION‐PG is functionalized through multistep organic transformations (–OH → –OTs (tosylate) → –N3 → –RGD) including click chemistry as a key step to impart targeting specificity by immobilization of cyclic RGD peptide (Arg‐Gly‐Asp‐D ‐Tyr‐Lys) on the surface. The targeting effect is demonstrated by the cell experiments; SPION‐PG‐RGD is taken up by the cells overexpressing αvβ3‐integrin such as U87MG and A549. 相似文献
16.
Novel Covalent organic skeleton/metal oxide (COF/MOx; M = Ti, Zn, Zr, Sn, Ce, Nb) Z scheme heterojunction is constructed to achieve highly selective oxidation of nitric oxide (NO). Under visible-light irradiation, the optimized COF/TiO2 (CF/TS0.05) catalyst showed an excellent NO removal rate (64.5%), resulting from the improvement of light absorption performance, the separation efficiency of photoexcited electron-hole pairs, and O2 activation due to the uniform coating of COF. Meanwhile, the electrons are captured by the adsorbed oxygen to effectively render into superoxide radicals as the main active species, and the corresponding holes are retained at the complex interface due to the hydrophobic COF coating, which extremely reduced the ability of activated water to produce hydroxyl radicals and limited the production of intermediate nitrogen dioxide (NO2), thereby improving the oxidation selectivity toward nitrate (NO3−) at 99.9% in the Z scheme heterojunction. More importantly, other COF/MOx catalysts also exhibited superior selectivity and activity, meaning that this scheme is credited with universality. In short, this study reveals that the generation of only one main reactive oxygen species is enhanced by reasonable control of electron-hole pair in the new Z scheme heterojunction to significantly increase photocatalytic performance and selectivity. 相似文献
17.
Chichao Yu Lingxia Zhang Jianlin Shi Jinjin Zhao Jianhua Gao Dongsheng Yan 《Advanced functional materials》2008,18(10):1544-1554
A facile method has been developed to synthesize nanoporous manganese and nickel oxides with polyhedron particle morphologies, high surface areas and narrow pore distributions by controlled thermal decomposition of the oxalate precursors. This method can be extended to using other kinds of salt precursors to prepare a series of nanoporous metal oxides. The heating rate, calcination temperature and controlled particle size of the oxalate precursors are important factors to get well‐defined pore structures. XRD, TG‐DTA, TEM, SEM, XPS, wet chemical titration and N2 sorption isotherm techniques are employed for morphology and structure characterizations. High surface area microporous manganese oxide (283 m2 g?1) and mesoporous nickel oxide (179 m2 g?1) with narrow pore distribution at around 1.0 nm and 6.0 nm, respectively, are obtained. Especially, we can tune the pore size of manganese oxides from microscope to mesoscope by controlling the thermal procedure. Electrochemical properties of manganese and nickel oxides are studied by cyclic voltammetry measurements in a mild aqueous electrolyte, which shows a high specific capacitance of 309 F g?1 of microporous manganese oxide and a moderately high specific capacitance of 165 F g?1 of mesoporous NiO due to their nanoporous structure, presenting the promising candidates for super capacitors (SC). 相似文献
18.
Soham Saha Benjamin T. Diroll Joshua Shank Zhaxylyk Kudyshev Aveek Dutta Sarah Nahar Chowdhury Ting Shan Luk Salvatore Campione Richard D. Schaller Vladimir M. Shalaev Alexandra Boltasseva Michael G. Wood 《Advanced functional materials》2020,30(7)
Transparent conducting oxides, such as doped indium oxide, zinc oxide, and cadmium oxide (CdO), have recently attracted attention as tailorable materials for applications in nanophotonic and plasmonic devices such as low‐loss modulators and all‐optical switches due to their tunable optical properties, fast optical response, and low losses. In this work, optically induced extraordinarily large reflection changes (up to 135%) are demonstrated in bulk CdO films in the mid‐infrared wavelength range close to the epsilon near zero (ENZ) point. To develop a better understanding of how doping level affects the static and dynamic optical properties of CdO, the evolution of the optical properties with yttrium (Y) doping is investigated. An increase in the metallicity and a blueshift of the ENZ point with increasing Y‐concentrations is observed. Broadband all‐optical switching from near‐infrared to mid‐infrared wavelengths is demonstrated. The major photoexcited carrier relaxation mechanisms in CdO are identified and it is shown that the relaxation times can be significantly reduced by increasing the dopant concentration in the film. This work could pave the way to practical dynamic and passive optical and plasmonic devices with doped CdO spanning wavelengths from the ultraviolet to the mid‐infrared region. 相似文献
19.
J. F. Kluender A. M. Jones R. M. Lammert J. E. Baker J. J. Coleman 《Journal of Electronic Materials》1996,25(9):1514-1520
A computational diffusion model is used to predict the lateral thickness and composition profiles of InxGa1−xP stripes grown by selective-area, atmospheric pressure metalorganic chemical vapor deposition. Standard profilometry is used
to measure the thickness profiles of InP and GaAs stripes grown on SiO2 patterned InP and GaAs substrates, respectively. The model is used to find self-consistent empirical diffusion parameters
for the In and Ga components which yield fits to the measured thickness data. The InP and GaAs data is then used to predict
the growth thickness profile of InGaP by a weighted sum of the predicted profiles of the InP and GaP binary constituents.
InGaP composition profiles are calculated by taking the ratio of the InP deposited volume to the InGaP deposited volume predicted
by the model at each of the simulation points. Predicted thickness profiles are verified by standard profilometry, and composition
profiles are verified by secondary ion mass spectrometry imaging using a fast resistive anode encoding detector. It is found
that the measured thickness and composition profiles agree well with the profiles predicted by the model, thus verifying that
the model can be used for the InGaP material system. The derived empirical parameters are used to predict the thicknesses
and compositions of selectively grown InGaP quantum wells as a function of oxide width. 相似文献
20.
In this paper, the thermoelectric properties of ZnO doped with Al, Bi and Sn were investigated by combining experimental and theoretical methods. The average Seebeck coefficient of Bi doped ZnO over the measured temperature range is improved from −90 to −497 μV/K. However, segregation of Bi2O3 in ZnO:Bi sample, confirmed by FESEM, lead to enormous grain growth and low electrical conductivity, which makes Bi is not a good dopant to improve ZT value of ZnO. As a 4+ valence cation, Sn doping actually show an increase in carrier concentration to 1020 cm−3, further enhancing the electrical conductivity. Unfortunately, the Seebeck coefficient of ZnO:Sn samples is even lower than pure ZnO sample, which lead to a low ZT value. As for ZnO:Al sample, with nearly no change in lattice thermal conductivity, electrical conductivity and Seebeck coefficient were both enhanced. Threefold enhancement in ZT value has been achieved in ZnO:Al sample at 760 °C compared with pure ZnO. 相似文献