ITO玻璃衬底上PLZT铁电薄膜的制备与电性能

用sol-gel法在掺Sn的In2O3导电透明膜(ITO)衬底上,制备了La掺杂的PbZr0.5Ti0.5O3(PLZT)铁电薄膜。研究了La掺杂量对薄膜的铁电、介电和漏电性质的影响。结果表明,x(La)为5%的PLZT薄膜经650℃退火,有优良的铁电特性,外加15V电压下,剩余极化强度为35.4×10–6C/cm2,矫顽场强为111×103V/cm。100kHz时的εr和tgδ分别为984和0.13。在外加电场小于9V时,薄膜的漏电流密度不超过10–8A/cm2。     

溶胶-凝胶法制备掺镧钛酸铅铁电薄膜的研究

采用溶胶-凝胶法在Pt／Ti／SiO2／Si衬底上制备了La掺杂的PbTiO3铁电薄膜(PLT)，X-射线衍射测量表明PLT薄膜呈高度(100)择优取向，原子力显微镜和扫描电子显微镜测量表明制备的PLT薄膜的表面平整、结构致密。RT66A测量表明PLT薄膜有优良的铁电特性，500kV／cm的外加电场下，剩余极化为10．6μC／cm^2，矫顽电场为55kV／cm。用HP4194A分析了薄膜的介电特性。100kHz时的介电常数为652。     

酚磺乙胺对酶法测定肌酐结果的影响

采用加入硅硼玻璃相的溶胶-凝胶(Sol-Gol)技术,以无机物为原料,在低温下成功制备了Pt/Ti/SiO2/Si衬底上Bi3.15La0.75Ti3O12(BLT)铁电薄膜.XRD、AFM分析及电学性能的测i式结果表明,600～650℃退火处理的加入硅硼玻璃相BLT铁电薄膜具有单一的层状钙钛矿结构;薄膜表面平整无裂纹、致密,薄膜为多晶生长;其剩余极化强度(2Pr)为27.09 μC/cm2,矫顽场E约为53.1 kV/cm;室温下,在测试频率为1 MHz,经1.0×1011极化反转后,剩余极化值下降约10%,具有良好的抗疲劳特性;薄膜的漏电流密度低于9×10-10 A/cm2.玻璃相提高了薄膜的致密度和抗疲劳特性,降低了薄膜的漏电流密度,对剩余极化强度影响有限.     

La掺杂对BLT薄膜微观结构与性能的影响

采用sol-gel工艺低温制备了Si基Bi4–xLaxTi3O12(BLT)铁电薄膜。研究了La掺杂量对薄膜微观结构、介电和铁电性能的影响。结果表明,600～650℃退火处理的BLT薄膜表面平整无裂纹,晶粒均匀,无焦绿石相或其它杂相,薄膜为多晶生长;La掺杂量x在0.5～0.85的BLT薄膜介电与铁电性能优良,其εr和tanδ分别介于284～289和(1.57～1.63)×10–2,4V偏压下薄膜的漏电流密度低于10–8A/cm2,Pr可达(13.0～17.5)×10–6C/cm2,Ec低至(102.5～127.8)×103V/cm。     

掺杂对PZT铁电陶瓷的介电铁电性能的影响

掺杂可以改变锆钛酸铅系铁电陶瓷的性能.着重对掺La3+、Mn2+对PZT陶瓷结构与性能的影响作了一些研究和探讨,通过对掺两种添加物的样品的介电、铁电性能的比较发现:掺La3+可以增大剩余极化值和损耗;掺杂Mn2+可以降低损耗;同时加入La3+、Mn2+可以调整PZT性能得到理想的效果:2Pr为80×10-6/cm2,tgδ为0.6×10-2.     

用陶瓷作内电极的BaTiO_3为基的致动器

本文研究了用陶瓷作内电极的多层陶瓷致动器的电致伸缩和机械性能。将绝缘的BaTiO_3和掺La的半导体BaTiO_3利用普通的生片成型法叠层并共烧结成多层结构。用差接变压器法测量了多层内电场诱致的应变。在15kV/cm电场下获得4×10~(-4)的应变量足以用于微动控制器件。获得的机械强度为50MN/m~2,约为用Pd作内电极的普通多层陶瓷致动器的3倍     

激光热冲击引起PZT压电薄膜铁电性能的变化

应用高能量单脉冲激光作用在锆钛酸铅 (PZT)压电薄膜上 ,研究脉冲激光的热冲击对PZT薄膜性能产生的影响。发现在激光未烧熔薄膜的能量密度下 ,经过激光作用后 ,PZT薄膜的铁电性能发生变化 :在外加电压为 6V时 ,剩余极化强度值Pr 从 32 6 99μC/cm2 变到 2 6 316 μC/cm2 ;矫顽电场保持为 38 396kV/cm不变 ;疲劳性能变稳定 ,在循环 1 75× 10 9次时 Pr 衰变率由 4 4 3%变为 34 7%。最后讨论分析了产生这种现象的微观机理。     

TiO_2过渡层对Bi_(3.54)Nd_(0.46)Ti_3O_(12)薄膜微观结构及电性能的影响

选取厚度为5、10和20nm的TiO2薄膜为过渡层,采用sol-gel法在Pt/Ti/SiO2/Si衬底上制备了Bi3.54Nd0.46Ti3O12(BNT)铁电薄膜,研究了过渡层厚度对铁电薄膜微观结构及电学性质的影响。结果表明,加入TiO2过渡层后,BNT薄膜微观结构得到改善,εr及2Pr值大幅提高,介电损耗及漏电流密度都有降低。过渡层厚度为20nm时,BNT薄膜的εr、tanδ及2Pr值分别为325、0.025(测试频率为10kHz)和36.1×10–6C/cm2,漏电流密度为8.45×10–7A/cm2(外加电场为100×103V/cm)。     

钨掺杂CaBi4Ti4O15基陶瓷的介电和铁电性能研究

用固相反应法制备了钨掺杂的铋层状结构铁电陶瓷Ca0.7La0.3Bi4(Ti1–xWx)4O15(x=0,0.025,0.100和0.200)。研究了钨掺杂对其介电、压电和铁电性能的影响。结果表明,当x<0.1时掺钨陶瓷已形成单晶相。Ca0.7La0.3Bi4(Ti0.975W0.025)4O15陶瓷具有最佳性能,其εr为183.15,tanδ为0.00446,d33为14pC/N,2Pr为26.7×10–6C/cm2,2Ec为220×103V/cm。SEM显示CaBi4Ti4O15基陶瓷的晶粒为片状。     

sol-gel法制备BiLaFeO3薄膜及其电性能

用sol-gel方法在LaNiO3包覆的Si衬底上制备了(010)择优取向的BiFeO3以及Bi0.95La0.05FeO3薄膜,XRD分析结果表明,通过La的掺杂BiFeO3的择优取向度由77.0%增加到96.6%;铁电性的测试表明,通过La掺杂,使薄膜的介电性和铁电性得到了增强,剩余极化强度由0.15×10–6C/cm2增加到0.2×10–6C/cm2。     

Characterization of Geoinspired and Synthetic Chrysotile Nanotubes by Atomic Force Microscopy and Transmission Electron Microscopy

Geoinspired synthetic chrysotile nanotubes both stoichiometric and 0.67 wt % Fe doped were characterized by transmission electron microscopy and electron diffraction. Bending tests of the synthetic chrysotile nanotubes were performed using the atomic force microscope. The nanotubes were found to exhibit elastic behaviour at small deformations (below ca. 20 nm). Young's modulus values of (159 ± 125) GPa and (279 ± 260) GPa were obtained from the force‐deflection curves using the bending equation for a clamped beam under a concentrated load, for the stoichiometric and the Fe doped chrysotile nanotubes, respectively. The structural modifications induced by Fe doping altered the mechanical properties, with an apparent dependence of the latter on the number of constituting walls of the nanotubes.     

Polypyrrole nanotube arrays on carbonized cotton textile for aqueous sodium battery

Polypyrrole (PPy) nanotubes on carbonized cotton textile have been prepared using ammonium vanadate nanowires as sacrificial templates, and characterized by scanning electron microscope, X-ray diffraction, fourier transform infrared spectrum and transmission electron microscope. The process contains cotton textile carbonation in Ar gas, growing ammonium vanadate nanowires on the carbon textile, electrodeposition PPy layer on the nanowire, and dissolving the ammonium vanadate nanowire core to obtain PPy nanotube. The results show that pyrrole is uniformly polymerized around the ammonium vanadate nanowires and the PPy nanotubes are firmly adhere to the carbon textile. The electrochemical properties of the PPy nanotubes for aqueous sodium-ion battery are investigated with cyclic voltammetry, galvanostatic charge-discharge test, and rate performance. The results exhibit a good electrochemical performance, which delivers a high discharge capacity of 108.8 mAh g⁻¹ over 100 cycles.     

躺在石墨表面上的碳纳米管

用扫描隧道显微镜 ( STM)测试分析了高定向石墨 ( HOPG)表面的碳纳米管 .在大气中室温下获得了碳纳米管原子结构 ,测量了碳管的 I- V特性 .结果表明 ,STM观察到的一般情况下的碳管容易呈簇集状态 ,与透射电镜 ( TEM)观察到的碳纳米管一致 ;在稀释和超声之后 ,STM观察到大量的单根碳管 .作者认为产生这种差别的原因 ,和碳管的疏水亲近效应强弱有关     

Fabrication and Electrical and Mechanical Properties of Carbon Nanotube Interconnections

Individual carbon nanotubes (CNTs) have been cut, manipulated, and soldered via electron‐beam‐induced deposition of amorphous carbon (a‐C) and using a scanning tunneling microscope inside a transmission electron microscope. All CNT structures, including simple tube–tube connections, crossed junctions, T‐junctions, zigzag structures, and even nanotube networks, have been successfully constructed with a high degree of control, and their electrical and mechanical properties have been measured in situ inside the transmission electron microscope. It is found that multiple CNTs may be readily soldered together with moderate junction resistance and excellent mechanical resilience and strength, and the junction resistance may be further reduced by current‐induced graphitization of the deposited a‐C on the junction.     

RF-PECVD法研究碳纳米管的生长特性

采用射频等离子体增强化学气相沉积(RF-PECVD),以Fe作为催化剂,在Si基片上生长了碳纳米管(CNT),采用扫描电子显微镜(SEM),高分辨透射电子显微镜(HR TEM)以及显微Raman光谱等对制备的CNT的形貌及结构进行了表征.结果表明:700℃和800℃温度下生长的CNT均取向无序、弯曲缠结,由整齐排列的圆...     

液化石油气燃烧火焰制备一维碳纳米材料

本文利用民用液化石油气为碳源,在经过预处理的低碳钢和含Ni合金钢等基板上成功地制备出“空心”碳纳米管(CNTs)和“实心”碳纳米纤维(CNFs)等一维碳纳米材料。实验发现基板预处理对一维碳纳米材料的制备起着决定性的作用,如：机械研磨预处理时很难制备出一维碳纳米材料,而采用涂覆和电镀处理则很容易获得一维碳纳米材料。利用场发射枪高分辨扫描电镜(SEM)、透射电镜(TEM)和激光拉曼光谱(RS)等技术对碳纳米材料的结构进行了表征。从本实验可以预见,制备一维碳纳米材料将变得更简单,更经济。     

A diameter-selective chiral separation of single-wall carbon nanotubes using nitronium lons

We propose a method for a diameter-selective removal of metallic single-walled carbon nanotubes (m-SWCNTs) from semiconducting (s-) ones. Our separation technique is capable of 100% separation of semiconducting and metallic nanotubes for small diameter nanotubes. We dispersed SWCNT powder by sonication in a mixed solution of tetramethylene sulfone and chloroform, where nitronium ions were well disolved. Positively charged nitronium ions were intercalated into nanotube bundles, where the intercalation was promoted also by the counter ions. Nitronium ions selectively attacked the sidewall of m-SWCNTs due to the abundant presence of electron density at the Fermi level, thus yielding stronger binding energy compared to the counterpart s-SWCNTs. The s-SWCNTs were left on the filter after filtration, whereas m-SWCNTs were perfectly destroyed by nitronium ions and drained away as amorphous carbons. This preferable adsorption became obscured for nanotubes with diameters greater than 1.1 nm. The effectiveness of removing m-SWCNTs was confirmed by the transmission electron microscope observations, x-ray photoemission spectra, resonant Raman spectra, and absorption spectra.     

Optoelectronic properties of solution synthesis of carbon nanotube/ZnO:Al:N nanocomposite and its potential as a photocatalyst

A novel multiwalled carbon nanotubes/aluminum–nitrogen co-doped ZnO (MWCNT/ZnO:Al:N) nanocomposite film was synthesized by a sol–gel deposition method and used for the photodegradation of organic dye under UV light illumination. The MWCNT/ZnO:Al:N composite film was extensively characterized through scanning electron microscope (SEM), Energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence measurements (PL) and UV–vis spectroscopy. Photocatalytic measurements reveal that the addition of MWCNT enhances photocatalytic degradation of MB by providing conduction path for electron transfer and reactive oxygen groups.     

In situ electrical measurements and manipulation of B/N-doped C nanotubes in a high-resolution transmission electron microscope

B/N-doped multiwalled C nanotubes were electrically probed by means of a tungsten needle attached to a piezo-driven stage of a high-resolution transmission electron microscope holder. Two-terminal transport measurements were performed in a 'W needle-nanotube-ground' circuit. The I-V curves were recorded in situ while viewing the nanotubes in the imaging mode of the microscope. This allows us to trace nanotube array morphological changes under applied voltage (up to 50 V). Specific manipulation with nanotube assemblies was found to be possible under applied electrical field: attachment of a tiny nanotube bundle to the W needle and extraction of a given nanotube fragment from an entangled complex bunch were achieved. The electrically-probed B/N-doped C nanotubes exhibited alternating B-rich and C-rich B-C-N domains within tubular layers, as revealed by elemental mapping during energy-filtered TEM (Omega filter). At room temperature the nanostructures displayed resistivity (rho) of approximately 1.8 x 10(-5) omegam and linear I-V curves. The key role of a given contact between the probing needle and a nanotube during electrical measurements was particularly verified.     

Anodic formation of aligned and bamboo-type TiO2 nanotubes at constant low voltages

Bamboo-type TiO2 nanotubes with a highly ordered structure on titanium surface were synthesized by a self-assembly electrochemical anodization in viscous glycerol solution at constant low voltages. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) were used to characterize the structure and morphology of the bamboo-type TiO2 nanotubes. The experimental results show that the morphologies of the nanotubes are markedly influenced by the viscosity (the water content) of the electrolytes solution, the anodization voltage and the anodization time. Besides, a possible formation mechanism for the bamboo-type TiO2 nanotubes was proposed.