α-Fe2O3薄膜的制备、结构和气敏特性

采用等离子增强化学气相淀积工艺(PECVD)制备出了Fe₂O₃薄膜。用X射线衍射(XRD)和扫描电子显微镜(SEM)分析了薄膜的结构、表面形貌和粒度。研究了薄膜对乙醇、液化石油气、煤气和氢气的敏感特性。结果表明所研制的薄膜对乙醇有较高灵敏度,其检测下限可达1ppm,而对液化石油气、煤气和氢气不太敏感,具有优良的选择性。     

双光束复合脉冲激光辐照沉积纳米金刚石薄膜

利用双光束复合脉冲激光辐照石墨悬浮液沉积技术,制备了高效率、高质量的纳米金刚石薄膜,成功解决了金刚石薄膜沉积不均匀和衬底温度对金刚石薄膜的影响。通过拉曼光谱仪和高分辨率透射电镜对薄膜的微观结构和组成进行了检测分析,实验结果表明,Raman光谱的D峰出现在1334cm-1处,G峰出现在1571cm-1处,沉积的薄膜致密均匀,晶粒平均尺寸在5nm左右。在制备过程中通过复合激光束辅以温度为金刚石薄膜的生长提供了更有利的条件,并在常温常压下连续制备出了粒度分布均匀的纳米金刚石薄膜。     

铁电薄膜非制冷红外探测器的技术发展

介绍了课题组在铁电薄膜的制备、特性研究以及非制冷红外探测技术方面的研究结果。研究获得了几种控制铁电薄膜微结构(如晶粒尺寸、晶粒形状、Ba_1-xSr_xTiO₃(BST)和PbZr_xTi_1-xO₃ (PZT)铁电薄膜的择优取向生长等)的新技术;研制出具有高度自极化特性的0.7Pb(Mg_1/3Nb_2/3)O₃-0.3PbTiO₃ (PMNT)弛豫铁电薄膜;探索了一种具有将红外转化为可见光机制的新型光读出方式;发明了PZT薄膜的低温(400 °C)生长方法。此外,还介绍了256×1线列铁电薄膜非制冷红外探测器的研制及部分成像结果。     

TiO2陶瓷晶界层电容器的研究

本文对TiO₂陶瓷晶界层电容器进行了较为系统的研究。用液相喷雾干燥法制备含Nb⁵⁺,Ba²⁺微量杂质的TiO₂超细原料粉末,研究了TiO₂陶瓷的电性能与烧结温度和测试条件的关系,阐述了TiO₂晶界层电容器的形成机制。     

WO3/NiWO4复合薄膜的制备及其光电化学性能

采用两步水热法在导电玻璃(FTO)上制备了WO₃/NiWO₄复合薄膜。通过XRD,SEM表征了WO₃/NiWO₄复合薄膜的组成结构及微观形貌,利用UV-Vis、光电流测试、光电催化测试和交流阻抗测试分析了WO₃/NiWO₄复合薄膜的光电性能。结果表明:WO₃/NiWO₄复合薄膜相较于WO₃薄膜具有更好的光吸收特性、光电流密度和光电催化活性,其中水热反应3h的WO₃/NiWO₄复合薄膜的光电化学性能最佳。WO₃/NiWO₄-3h在1.4V(vs.Ag/AgCl)时的光电流密度为1.94mA/cm²,光电催化210min对亚甲基蓝溶液的降解效率为57.1%。交流阻抗图谱表明WO₃/NiWO₄薄膜的电荷转移电阻小于WO₃薄膜,光电化学性能更优。     

大面积ReS2微结构的制备及表征

采用化学气相沉积法(Chemical Vapor Deposition,CVD),通过控制生长温度和时间,在氟金云母衬底(KMg₃(AlSi₃O₁₀)F₂)上制备出大面积、高质量的ReS₂层状薄膜、纳米片、纳米花等微结构。利用拉曼显微镜(Raman)、光致发光光谱(PL)、原子力显微镜(AFM)、X射线光电子能谱分析(XPS)、扫描电子显微镜(SEM)及能谱仪(EDS)对所制备的ReS₂结构进行表征。结果显示:ReS₂能够在表面平整且为惰性的氟金云母衬底上实现大面积高质量的面内、外生长;面外生长的ReS₂纳米片和纳米花结构的拉曼光谱相对于层状的ReS₂结构在207cm-1附近的特征峰处存在红移现象,在163cm-1附近的特征峰相对强度不断减弱;ReS₂微结构的PL峰的位置基本无变化,但是峰值强度随面外生长而不断减弱。     

异质三明治结构柔性薄膜压电纳米发电机研究

采用旋涂法制备不同质量分数还原氧化石墨烯(rGO)的PVDF/rGO复合薄膜。采用层层堆叠法构建层层组装异质三明治结构(PVDF/rGO-PVDF-PVDF/rGO)的压电纳米发电机(PNG)。系统研究了rGO掺杂、异质结构设计对压电输出性能的影响。研究结果表明，在掺杂rGO质量分数为0.4%时，单层PVDF/rGO复合薄膜压电纳米发电机的开路电压达到1.76 V，短路电流达到0.18 μA。层层组装异质类三明治结构PVDF/rGO_0.4-PVDF-PVDF/rGO_0.4的PNG，开路电压高达7.72 V，是单层PVDF/rGO复合PNG的4.39倍；短路电流可达0.69 μA，是单层PVDF/rGO复合PNG的3.83倍，这促进了电荷的转移，提高了电荷利用率。PVDF/rGO_0.4-PVDF-PVDF/rGO_0.4复合层层异质结构PNG经过4 000次循环敲击测试，三层异质复合PNG压电输出稳定，有望在柔性可穿戴电子器件、人机交互及电子皮肤等领域得到广泛应用。     

BaTiO3铁电纳米膜制备及物性和微结构表征

采用脉冲激光淀积法在硅基氧化铝纳米有序孔膜版介质上（膜版孔径平均尺寸20nm,内生长Pt纳米线作为底电极一部分）制备了BaTiO3铁电纳米膜,并对其物性（铁电和介电性能）和微结构进行了表征。结果表明厚度170nm BaTiO3铁电膜的介电常数,随着测量频率的增加（103Hz至106Hz）,从400缓慢下降到350;介电损耗在低频区域（103～105Hz）从0.029缓慢增加到0.036,而在高频率区域（〉105Hz）后,则迅速增加到0.07。这是由于BaTiO3铁电薄膜的介电驰豫极化引起的。电滞回线测量结果表明,该薄膜的剩余极化强度为17μC/cm2,矫顽场强为175kV/cm。剖面扫描透射电子显微镜（STEM）图像表明,BaTiO3纳米铁电薄膜与底电极Pt纳米线直接相连接,它们之间的界面呈现一定程度的弯曲。选区电子衍射图和高分辨电子显微像均表明BaTiO3铁电薄膜具有钙钛矿型结构。在BaTiO3纳米铁电薄膜退火晶化处理后,部分Pt纳米线的再生长导致顶端出现分枝展宽现象。为了兼顾氧化铝纳米有序孔膜版内的金属纳米线有序分布和BaTiO3纳米薄膜结晶度,合适的退火温度是制备工艺过程的关键因素。     

多层PT/PZT薄膜的结构特性研究

通过溶胶-凝胶（Sol-Gel）法在Pt/Ti/SiO2/Si基底上制备了多层PT/PZT（PbTiO3/Pb(Zr0.52Ti0.48)O3）薄膜,研究了不同退火时间对其纳米结构、结晶性能及相变特性的影响。利用FESEM测试了不同退火时间对薄膜纳米结构的影响,选用XRD与Raman分析了薄膜的结晶取向及相变特点。实验结果表明,随着退火时间的增加,薄膜的三方相向四方相转变,并具有（110）择优取向。退火时间为20 min是PZT薄膜的最佳退火时间,此时薄膜的结晶效果良好、晶粒大小均匀、具有纯钙钛矿结构,此种结构的薄膜有望应用于MEMS器件中。     

集成运算放大器同相和反相形式的En-In噪声分析和比较

本文通过分析和比较同相和反相放大器E_n-I_n噪声的特点,给出了若干新结果。本文方法在低噪声运放电路设计和运放噪声参数提取中都具有十分重要的意义。     

钙钛矿氧化物薄膜和异质结的外延生长与物性研究

用激光分子束外延，原子尺度控制的外延生长出多种钙钛矿氧化物薄膜和异质结．原子力显微镜和高分辨透射电镜测量结果表明，薄膜与异质结的表面和界面均达到原子尺度的光滑．制备出在可见光波段透过率大于85％的导电氧化物薄膜；物性研究结果表明，随着含氧量的不同，BaTiO3薄膜具有绝缘体、半导体和导体的不同特性。BaTiO3／SrTiO3超晶格的光学非线性效应比BaTiO3体材增大23倍．首次在La0．9Sr0．1MnO3／SrNb0．01Ti0.99O3(LSMO／SNTO)异质结上，观测到全氧化物p-n结电流和电压的磁调制与正磁电阻效应。在255K条件下，当外加磁场分别为5和1000Oe时，LSMO／SNTO p-n结的磁电阻变化率R／RO达到：46．7％和83．4％；在外加磁场为3T时，在100K条件下，在LSMO／SNTO多层p-n异质结上观测515％的正磁电阻变化率。     

BaTiO3超薄膜的制备和性能研究

用LB(Langmuir Blodgett)膜技术制备的BaTiO3超微粒–硬脂酸复合LB膜,热处理后形成BaTiO3超薄膜。用紫外–可见光吸收光谱、电子自旋共振、红外光谱和X射线衍射对BaTiO3超薄膜进行研究。BaTiO3超薄膜在190~287 nm范围内具有明显的吸收,而在299 nm附近有强烈的吸收;超薄膜中的BaTiO3微粒存在氧空位,分子内部结构和晶体结构都发生了明显的变化。     

Effect of annealing on Zn1−xCoxO thin films prepared by electrodeposition

Polycrystalline thin films of Zn_1−xCo_xO with different cobalt (Co) content were grown on indium tin oxide (ITO) substrates by cathodic electrodeposition technique and subsequently annealed in air at 400 °C. The effect of annealing in their structural, optical and chemical properties has been characterized by X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman scattering and optical spectroscopy. Our measurements indicate that moderate annealing increases the crystal quality of the films. The films are highly transparent in the visible range and evidence an increase of the band gap and of the intensity of three typical Co absorption bands in the visible with the amount of Co. Thermal annealing produces an increase of the intensity of the Co²⁺-related absorption bands revealing that higher amount of Co atoms are occupying Zn sites.     

Ba_(0.99)Nd_(0.01)TiO_3纳米颗粒的合成及其光学性能研究

用熔盐法合成了掺Nd钛酸钡(Ba0.99Nd0.01TiO3)纳米颗粒,用X射线衍射、透射电镜和拉曼光谱研究了所制Ba0.99Nd0.01TiO3纳米颗粒的晶体结构,讨论了Nd掺杂对BaTiO3结构的影响,并分析了纳米颗粒的紫外–可见光吸收和光致发光性能。结果表明:合成的纳米颗粒是单晶的四方结构,平均粒径约为200 nm,光学带隙为3.23 eV。在近红外波段900 nm和1 060 nm附近有强烈发光,其分别是由Nd3+的4F3/2→4I11/2和4F3/2→4I13/2跃迁辐射导致。     

Epoxy/BaTiO/sub 3/ composite films and pastes for high dielectric constant and low-tolerance embedded capacitors fabrication in organic substrates

Epoxy/BaTiO/sub 3/ composite embedded capacitor films (ECFs) were newly designed for high dielectric constant and low-tolerance (less than /spl plusmn/5%) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of a specially formulated epoxy resin and latent curing agent, and in terms of a coating process, a comma roll coating method is used for uniform film thickness in large area. The dielectric constant of ECF in high frequency range (0.5/spl sim/3 GHz) is measured using the cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. The dielectric constant is calculated by observing the frequencies of the resonant cavity modes. Calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of the epoxy matrix. The dielectric relaxation of barium titanate (BaTiO/sub 3/: BT) powder is not observed within measured frequency. An alternative material for embedded capacitor fabrication is epoxy/BaTiO/sub 3/ composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming a capacitor partially in the desired part. However, the screen printing makes surface irregularities during mask peel-off. Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, a dielectric layer with improved thickness uniformity is successfully demonstrated. Using epoxy/BaTiO/sub 3/ composite ECP, a dielectric constant of 63 and specific capacitance of 5.1 nF/cm/sup 2/ were achieved.     

Formation of Hybrid Inorganic/Organic Nanocomposites

Hybrid inorganic/organic nanocomposites were produced by the exposure of spun films of octa-(benzo-15-crown-5)-substituted phthalocyanine of Cd(II) to an environment of hydrogen sulfide gas. The formation of cadmium sulfide (CdS) quantum dots in the metal free phthalocyanine matrix was identified in the phthalocyanine matrix from atomic force microscopy images. The mean size of CdS quantum dots was estimated to be 2–3 nm, from optical absorption and Raman spectra for the nanocomposites.     

金刚石薄膜的人工合成及其结合力的评估

在硬质合金ＷＣ—Ｃｏ基体上，用热丝ＣＶＤ法，人工合成出金刚石薄膜。利用Ｘ衍射、激光拉曼光谱和扫描电镜对金刚石薄膜的结构进行了测定，结果是令人满意的。精确测量金刚石薄膜与基体间的结合力是很困难的。本文报导了金刚石薄膜涂层刀具的实际切削结果，并以此来评估该涂层与基体间的结合力。     

Interactions between ferroelectric BaTiO3 and Si

Ferroelectric BaTiO₃ thin films were deposited on single crystal Si substrates by radio-frequency magnetron sputtering. Bilayer structures of BaTiO₃ thin films, either amorphous on polycrystalline (A/P) or polycrystalline on microcrystalline (P/M), were utilized to reduce the leakage current and to enhance the dielectric constant of the films compared to single polycrystalline and amorphous layer structures, respectively. Relatively lower charge density, determined by the capacitance-voltage measurement on the capacitors with a configuration of Au/ BaTiO/p-Si/Al, was detected for the BaTiO₃ thin film with a structure of P/M. The current-voltage characteristics of the Al/SiO₂(~1.8 nm)/p-Si/Al diodes fabricated on the Si after removing BaTiO₃ layers gave direct evidence of the preservation of the Si surface crystal by using a P/M instead of a A/P structure. This was further confirmed by the Auger electron spectroscopy analysis on the samples.     

Cover Picture: Thermotropic Liquid Crystals as Substrates for Imaging the Reorganization of Matrigel by Human Embryonic Stem Cells (Adv. Funct. Mater. 5/2006)

New approaches to the culture of cells and measurements of cell–extracellular‐matrix interactions are suggested in the Full Paper by Abbott and co‐workers on p. 618. The culture of human embryonic stem cells (hESCs) on interfaces of a thermotropic liquid crystal that are decorated with thin films of the extracellular matrix, Matrigel, are investigated. The cover image shows the polarized light microscopy image of hESCs cultured for three days on a Matrigel‐coated film of liquid crystal hosted within a TEM grid. The hESCs reorganized the Matrigel, leading to patterned orientations of the liquid crystal. We have investigated the culture of human embryonic stem cells (hESCs) on interfaces of the thermotropic liquid crystal, TL205, that are decorated with thin films of the extracellular matrix, Matrigel. hESCs seeded at the liquid‐crystal/Matrigel interface survive for weeks, and cell colonies grow over this time. The cells show levels of differentiation comparable to that observed for cells on Matrigel‐coated glass controls. Polarized and fluorescence microscopy reveal that the orientational order of the liquid crystal is coupled to the presence and organization of Matrigel. This enables straightforward imaging of the reorganization of Matrigel by the hESCs through changes in the appearance of the liquid crystal when observed using polarized light microscopy. The coupling between Matrigel and TL205 thus provides a simple tool for monitoring the reorganization of the Matrigel film over time. Our results suggest new approaches to the culture of cells and measurements of cell–extracellular‐matrix interactions.     

Sb掺杂BaTiO_3的电磁及微波吸收特性研究

以BaCO3、TiO2、Sb2O3为原料,采用固相法制备了Sb掺杂BaTiO3样品,借助XRD、Raman光谱以及矢量网络分析仪等分析测试手段对所制样品的晶相、晶格常数、电磁性能及微波吸收特性进行了表征。结果表明:低掺杂Sb的样品均为单一四方相BaTiO3晶体,结晶良好;随着w(Sb2O3)的增大,晶格常数减小;与未掺杂的BaTiO3相比,Sb掺杂BaTiO3的反射损耗明显提高,且反射峰向低频方向偏移;当w(Sb2O3)为0.6%时,制得BaTiO3的反射损耗在3.7 GHz处达到最大值–28.2 dB。