一种纳米孔洞阵列金膜制备方法

以多孔阳极氧化铝膜(anodic aluminum oxide,AAO)为模板,用磁控溅射的方法制备纳米孔洞阵列金膜,SEM结果表明,制备得到的纳米孔洞阵列金膜形貌与AAO模板形貌一致,孔洞阵列规则,孔径大小均匀。此方法适合于纳米孔洞阵列金膜的复制,为纳米线、量子点等纳米阵列材料的组装与合成提供新的条件。     

矩形块微纳结构材料在红外波段的偏振光吸收

研究了矩形块微纳结构吸收材料在中远红外波段的光学偏振吸收特性。该吸收材料由金属阵列-电介质层-金属膜组成,在2.0μm~5.0μm波长具有双波长谐振吸收效应,其理论吸收率大于80%。模拟计算和实验测试表明,该吸收材料的短波吸收峰值与矩形块长轴方向入射偏振光的3阶谐振响应对应,而长波吸收峰值与短轴方向基模谐振响应对应。实验制备了矩形阵列光吸收器并测试了它的的光学特性,结果表明:该吸收器结构在两个偏振方向的等效磁导率系数满足Lorentz模型,等效磁导率谱线虚部峰值波长与吸收谐振波长相对应,表明这种吸收材料的偏振吸收与入射电磁波的磁谐振响应有关。研究结果揭示了微纳结构吸收器的双波长频谱吸收机理,有助于实现特定波长生物传感器及光电探测器的设计。     

氧化铝模板制备镍纳米阵列

阳极氧化铝模板合成技术是近年发展起来的纳米结构材料组装的最重要的技术之一，是目前纳米材料研究中的一个热点。与其它方法相比，具有很多优点。目前，应用此模板已合成出多种金属纳米阵列。由镍制得的纳米阵列有许多优良的性质，具有广泛的应用价值和前詈。本文以纳米孔的多孔氧化铝膜作为模板，采用电化学沉积法在孔内合成出高度有序的镍纳米阵列体系。并对制备出的氧化铝模板及镍纳米阵列进行XRD，TEM及SEM表征。     

光通讯用低PDL线性渐变衰减滤光片

计算了渐变衰减滤光片的偏振相关损耗,分析了镀膜工艺对偏振相关损耗的影响,提出了降低偏振相关损耗的方法。采用线性迭代修正法和膜厚分布可调控制技术,提高了渐变衰减滤光片的线性度。制造出线性度小于5%、偏振相关损耗小于0.08dB的高性能渐变衰减滤光片。     

研究人员提出金属陶瓷超材料薄膜制备新方法

<正>中国科学院宁波材料技术与工程研究所提出了一种金属陶瓷超材料薄膜制备新方法,该方法采用传统的射频共溅射沉积工艺,辅以衬底偏压,制备了定向排布Ag金属纳米线/氧化铝陶瓷复合超材料薄膜,纳米线间距(轴心到轴心)进入sub-5 nm区间,阵列中纳米线平均直径约为3 nm;纳米线长径比可根据沉积时间来灵活调整;利用PVD     

基于等效层理论的薄膜滤光片中心波长消偏振膜系设计

针对薄膜滤光片倾斜入射时产生的偏振光中心波长分离现象和偏振相关损耗,本文利用等效层理论设计了倾斜入射下中心波长消偏振的100GHz信道间隔滤光片膜系结构,实现了薄膜滤光片的角度和波长调谐。首先通过相位关系分析,计算了滤光片间隔层的消偏振等效折射率,实现了不同偏振光中心波长的对准。然后,根据等效层理论,设计三层对称膜层结构实现了对间隔层中心波长消偏振等效折射率的替换。与原有的五层规整低偏振薄膜滤光片相比,本文提出的膜系结构更为简单,对消偏振等效折射率的替换更为精确。仿真和实验结果表明:该膜系结构的薄膜滤光片能实现0~20°倾斜入射的偏振光中心波长对准,偏振光波长偏离度小于0.03nm,波长调谐范围能达到35nm。     

微偏振片阵列红外成像非均匀性产生机理及其校正

集成微偏振片阵列红外成像系统的偏振度图像对非均匀性高度敏感,不经非均匀校正的偏振度图像存在较大误差。为了校正微偏振片阵列红外成像的非均匀性,以入射光Stokes矢量形式,建立了光电转换基本过程的偏振像素模型,基于入射激励和辐射响应数据,分析了微偏振阵列与红外焦面联合作用下非均匀性产生机理。提出一种基于多次辐射测量的矩阵形式的非均匀性校正方法,该方法通过构造多组测量方程,求解偏振像元的增益矢量,由相邻四像元增益矢量组成超级像元的增益矩阵,结合Stokes矢量提取矩阵,逆向求解重构点的校正矩阵。实验数据表明:该方法比两点法降低非均匀性约5%~20%,有效改善红外偏振度图像质量。     

偏振态、相位和振幅对受激辐射损耗中损耗光焦斑的影响

针对受激辐射损耗(STED)超分辨显微术分辨率不够高的问题,研究了损耗光偏振态、相位和振幅多种物理量对焦斑的影响,以形成半峰全宽窄的圆环形损耗光焦斑。根据Richards-Wolf矢量衍射理论,建立了偏振态、相位和偏振态作用下的损耗光焦斑模型;计算了不同偏振态、不同相位振幅调制参数下损耗光焦斑的分布情况;通过优化各参量得到有效激发荧光的分布。计算结果表明,应用切向偏振时的损耗光焦斑半峰全宽优于应用径向偏振和圆偏振;相位和振幅的调制作用均能减小半峰全宽;优化后有效激发荧光的理论半峰全宽仅为13.2nm。采用损耗光的偏振态、相位和振幅对损耗光焦斑进行整形,能够有效减小半峰全宽,获得较高的理论分辨率,比仅使用单一物理量的效果更好;应用切向偏振光能够获得高质量的损耗光焦斑和超衍射极限的分辨能力,根据不同实际情况选择相位或振幅调制的方法可进一步提高分辨率。     

分枝铜纳米线的近红外偏光特性

利用2次阳极氧化法制备了具有分枝结构的多孔铝模板,并在该模板中合成了Cu纳米线.多孔铝模板的上下表面和复合结构的侧面SEM形貌表明,我们制备出了具有分枝结构的多孔铝模板以及Y形分枝状Cu纳米线.测量了样品的透射光谱和偏振光谱,试验发现,具有分枝结构的多孔铝模板在近红外光区的透射率达到了90%,可以作为近红外偏振器件的模板;含Y形分枝状Cu纳米线结构多孔铝膜在近红外光区具有较高的透射率和较好的偏振性能,本试验中得到了15～18 dB的消光比以及0.1～0.3 dB的低插入损耗.     

有序金纳米棒阵列的超分辨成像

显微成像技术受限于光学成像系统的衍射极限，无法分辨亚波长尺度的结构。通过饱和散射抑制成像技术已经实现了单个纳米颗粒的超分辨成像，但是涉及到纳米颗粒集合，需要考虑纳米颗粒间的耦合作用。利用超越衍射极限的双光束方法，可以在有序金纳米棒阵列上实现远场超分辨光学成像。本文设计了纳米棒长径比为2的5×5金纳米棒阵列，通过矢量光场理论和热扩散理论计算了金纳米棒阵列在连续波激光下的热分布，并模拟了双光束激光即脉冲激发光和连续波抑制光下的散射成像。仿真结果显示，连续波激光能够有效抑制金纳米棒阵列对脉冲激光的散射，双光束方法实现了80 nm横向特征尺寸的超分辨成像。     

Synthesis and characterization of Ag–Co–Ni nanowires

This work provides an electrodeposition‐based methodology for synthesizing multicomponent nanowires containing Ag, Co and Ni atoms. Nanowire morphology was obtained by using an anodic alumina membrane with cylindrical pores of ～200‐nm diameter. Structural, compositional and magnetic characterization revealed that the as‐synthesized nanowires adopted a core–shell microstructure. The core (axial region) contained pure Ag phase volumes with a plate‐like morphology oriented perpendicular to the nanowire axis. The shell (peripheral region) contained pure Ag nanoparticles along with superparamagnetic Co and Ni rich clusters.     

Analysis of effect of nanoporous alumina substrate coated with polypyrrole nanowire on cell morphology based on AFM topography

In this study, in situ electrochemical synthesis of polypyrrole nanowires with nanoporous alumina template was described. The formation of highly ordered porous alumina substrate was demonstrated with Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). In addition, Fourier transform infrared analysis confirmed that polypyrrole (PP) nanowires were synthesized by direct electrochemical oxidation of pyrrole. HeLa cancer cells and HMCF normal cells were immobilized on the polypyrrole nanowires/nanoporous alumina substrates to determine the effects of the substrate on the cell morphology, adhesion and proliferation as well as the biocompatibility of the substrate. Cell adhesion and proliferation were characterized using a standard MTT assay. The effects of the polypyrrole nanowires/nanoporous alumina substrate on the cell morphology were studied by AFM. The nanoporous alumina coated with polypyrrole nanowires was found to exhibit better cell adhesion and proliferation than polystyrene petridish, aluminum foil, 1st anodized and uncoated 2nd anodized alumina substrate. This study showed the potential of the polypyrrole nanowires/nanoporous alumina substrate as biocompatibility electroactive polymer substrate for both healthy and cancer cell cultures applications.     

Electron microscopy of Ag–(Ni–O) core–shell nanowires

This report provides information about an electrodeposition‐based two‐step synthesis methodology for producing core–shell Ag–(Ni–O) nanowires and their detailed structural and compositional characterization using electron microscopy technique. Nanowires were produced by employing anodic alumina templates with a pore diameter of 200 nm. In the first step of the synthesis process, nanocrystalline Ni–O was electrodeposited in a controlled manner such that it heterogeneously nucleated and grew only on the template pore walls without filling the pores from bottom upwards. This alumina template with pore walls coated with Ni–O was then utilized as a template during the electrodeposition of Ag in the second step. Electrodeposited Ag filled the template pores to finally produce Ag–(Ni–O) core–shell nanowires with an overall diameter of 200 nm.     

Manipulating InAs nanowires with submicrometer precision

InAs nanowires are grown epitaxially by catalyst-free metal organic vapor phase epitaxy and are subsequently positioned with a lateral accuracy of less than 1 μm using simple adhesion forces between the nanowires and an indium tip. The technique, requiring only an optical microscope, is used to place individual nanowires onto the corner of a cleaved-edge wafer as well as across predefined holes in Si(3)N(4) membranes. The precision of the method is limited by the stability of the micromanipulators and the precision of the optical microscope.     

Effects of Electrochemistry on Surface Roughness during Chemical-Mechanical Polishing of Copper

In this research, we investigated the electrochemical behavior of copper (Cu) surfaces during chemical-mechanical polishing (CMP) with alumina containing slurries. The variation of pH and the percent of oxidizer were tested against impressed anodic and cathodic potentials. The polarization curves as well as potential and current values were measured in order to investigate the effects of electrochemical interactions during polishing. The polishing performance was evaluated through friction, wear, and surface quality. Surface characterization was conducted using an atomic force microscope. The areas scanned contained surfaces having different post-CMP surface chemistry. In such, the electrochemical, chemical, and mechanical action could be revealed and compared in situ and simultaneously. Research results showed that in acidic environment, the low pH dominated the surface roughness over oxidizer and anodic current. At high pH, however, oxidizer and anodic current played important roles. As a result, an optimized polishing condition was proposed.     

SnO2纳米线的合成及应用动态

在分析比较SnO2纳米线各主要制备方法的基础上,首次以金属Sn为锡源,采用自蔓延高温合成一喷射法制备了SnO2纳米线,并进行了SEM、XRD、HRTEM表征。同时,综述了SnO2纳米线的气敏性能、场发射性能和光学性能的研究现状,介绍了SnO2纳米线的几种典型应用。     

金属电极材料对YSZ氧传感器性能的影响

借助循环伏安和计时电流方法,研究了金属电极材料对YSZ氧传感器性能的影响。结果表明,在500℃和空气条件下,Ag-1%Pd/YSZ电极由于具有合适的微观结构以及较强的氧扩散能力,使其无论是作为YSZ氧传感器的阳极还是阴极,性能均为最好,而Au/YSZ电极最差;各金属/YSZ电极具有相似的阳极极化计时电流曲线,其电流密度值在10 s之内即可达到平稳;随着阳极阶跃极化电位增大,使得参加电极还原反应的氧原子数量增加,从而导致Ag-1%Pd/YSZ电极电流密度稳定值亦增大。     

EELS and optical response of a noble metal nanoparticle in the frame of a discrete dipole approximation

Surface plasmons of noble metal nanoparticles have recently been studied by Electron Energy-Loss Spectroscopy (EELS) performed in an electron microscope. We present here the basic formalism for EELS simulations in a Discrete Dipole Approximation (DDA) framework for such surface excitations. We compare EELS data and optical properties of a silver triangular nanoprism and show that the spatial variation of surface plasmon excitation probabilities allows to discriminate modes of similar energies. We also emphasize the importance of the substrate polarization effect to reliably describe experimental data.     

Surface-enhanced Raman scattering by semiconductor nanostructures

Surface-enhanced Raman scattering by optical and surface phonons in CdS, GaN, and CuS nanocrystals, and AlN nanowires is detected and studied. It is found that the presence of metal (Ag, Au, and Pt) nanoclusters noticeably modifies the Raman spectra of the nanostructures and results in a resonant increase in the intensity of optical phonon modes in CdS and CuS nanocrystals or in the emergence of surface modes in GaN nanocrystals and AlN nanowires. It is shown that the frequencies of the surface optical phonon modes of the examined nanostructures are in good agreement with the theoretical values calculated within the framework of the dielectric continuum model.     

Eco-Friendly Synthesis of Colloidal Silver Nanospheres,Nanorings, and Nanonetworks

Abstract

Colloidal silver nanospheres, nanorings, and nanonetworks were synthesized by the nanosecond pulsed laser ablation of a silver metal plate in a pure distilled water (at room temperature) using the fundamental (1064 nm), second harmonic (532 nm), and third harmonic (355 nm) wavelengths of the Nd:YAG laser, respectively. The products were characterized by means of both transmission electron microscopy (TEM) and optical absorption spectroscopy. The TEM data show the formation of silver nanospheres, nanorings, and nanonetworks. On the other hand, optical spectra reveal the occurrence of the red shift of the peak associated with the surface plasmon resonance (SPR) of silver nanorings and nanonetworks. A possible explanation for the formation of above stated silver nanostructures is being discussed.