图案化金属铜纳米线阵列的制备与表征

采用紫外线光刻技术与电化学沉积相结合的方法,成功制备了不同图案的铜纳米线阵列:一种是圆形图案;另一种是QDU图案.首先利用紫外线光刻技术在多孔阳极氧化铝模板(AAO)生成预设图案,以此作为"二次模板";再利用电化学方法将铜纳米线沉积到"二次模板"的开孔中.扫描电镜(SEM)测试结果表明,大面积、高规整的铜纳米线图案阵列各自独立地立在基底上, 同时,用电子能谱(EDS)分析了铜纳米线的化学成分.透射电镜(TEM)也探测到了铜纳米线的微结构.     

Template-based fabrication of nanowire-nanotube hybrid arrays

The fabrication and structure characterization of ordered nanowire-nanotube hybrid arrays embedded in porous anodic aluminum oxide (AAO) membranes are reported. Arrays of TiO(2) nanotubes were first deposited into the pores of AAO membranes by a sol-gel technique. Co?nanowires were then electrochemically deposited into the TiO(2) nanotubes to form the nanowire-nanotube hybrid arrays. Scanning electron microscopy and transmission electron microscopy measurements showed a high nanowire filling factor and a clean interface between the Co nanowire and the TiO(2) nanotube. Application of these hybrids to the fabrication of ordered nanowire arrays with highly controllable geometric parameters is discussed.     

Synthetic control of large-area, ordered silver nanowires with different diameters

Silver (Ag) nanowires with different diameters (28, 38, 55, 80, 200 nm) have been successfully fabricated into the anodic alumina membranes (AAMs) by direct-current electrochemical deposition technique. X-ray diffraction and selected area electron diffraction analysis show that the as-synthesized samples have preferred (220) orientation independent of the nanowire diameters. Transmission electron microscopy and field-emission scanning electron microscopy investigation reveal that the large-area and highly ordered Ag nanowire arrays with smooth surface and uniform diameter are synthesized, and they have the high aspect ratio. The formation mechanism of the silver nanowires is also discussed. The nanowire arrays with different diameters may have potential applications in the future nanodevices.     

Room-temperature synthesis of high-density CuS nanowire arrays by a simple paired cell

High-density CuS nanoparticle nanowire (NPNW) arrays were successfully synthesized at room temperature by a simple paired cell method. The as-prepared nanowire arrays were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The results indicate that the nanowire diameter is dependent on the pore size of the used ordered porous anodic alumina (OPAA) template and larger than the corresponding pore diameter of the template due to the corrosion effect of Na2S solution on the template. The nanowire is composed of CuS nanoparticles with hexagonal structure. When the reaction time is long enough, the nanowire is solid and composed of nearly spherical CuS nanoparticles. When the reaction time is short, only middle part of the nanowire is solid and composed of nearly spherical CuS nanoparticles, however, the tops are hollow and mainly composed of flake-like nanoparticles. The formation mechanism of CuS nanoparticle nanowires was proposed to be a heterogeneous nucleation, coalescence, aggregation and filling process.     

Fabrication and magnetic properties of Fe<Subscript>3</Subscript>Co<Subscript>7</Subscript> alloy nanowire arrays

Fe₃Co₇ alloy nanowire arrays have been fabricated by direct current electrodeposition of Fe²⁺ and Co²⁺ into anodic aluminum oxide (AAO) templates. The phase structure and magnetic properties of the nanowires were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). Magnetic measurements show that the coercivity and remanence of the as-deposited Fe₃Co₇ Alloy nanowires increase dramatically after heat-treatment at 773 K for 2 h, and the nanowire arrays exhibit uniaxial magnetic anisotropy with easy magnetization direction along the nanowire axes owing to the large shape anisotropy. The great difference between practical coercivity and ideal coercivity was also discussed in detail.     

Superconducting Properties of Pb/Bi Films Quench-Condensed on a Porous Alumina Substrate Filled with Co Nanowires

Superconducting properties of a new ferro-magnet–superconductor hybrid structure have been investigated. Organized arrays of Co nanowires are first electroplated into the columnar pores of anodic aluminum oxide (AAO) membranes. Superconducting Pb/Bi (18 at.%) films are then quench-condensed onto the surface of the AAO membranes filled with Co nanowires. The Co nanowire array produces a magnetic field with a strong spatial variation in the superconducting film. Hysteretic superconducting properties and enhanced critical currents have been observed in applied external magnetic fields, which we explain based on the magnetic domain structure of the Co nanowire arrays.     

Well-defined nanoarrays from an n-type organic perylene-diimide derivative for photoconductive devices

Well-defined one-dimensional (1D) perylene-diimide derivative (PDD) nanowire arrays were prepared via a simple electrophoretic deposition method by using anodic aluminum oxide (AAO) templates. The morphology of the as-deposited films was characterized by field emission scanning electron microscope and transmission electron microscopy. The highly ordered nanoarrays were free-standing after removing the AAO supports. Further studies revealed that the growth process of the nanowires in the AAO pores followed a 'bottom-up' growth model. A photoreceptor with PDD nanowire arrays as the charge generation layer was fabricated. It exhibited a better photoconductivity under light illumination when compared to that of its bulk counterpart. Our results suggested that electron-accepting PDD nanowire arrays can be used as a potential candidate for photoconduction devices, which would facilitate further exploration of new technological applications of the photoimaging process.     

模板法合成分叉Ni纳米线阵列及其磁性能

首先采用三次阳极氧化法制备了具有Y形孔道的氧化铝(AAO)模板,然后采用直流电化学沉积法,在模板内成功合成了分叉Ni纳米线的有序阵列.通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对所合成样品的晶体结构和形貌进行了表征测试.结果表明,制备的Ni纳米线分布均匀、排列有序,呈Y形分又结构,其...     

交流电化学沉积FeCo合金纳米线阵列及其磁性能研究

采用二步阳极氧化法制备孔结构高度有序的多孔氧化铝(AAO)模板。在不同Fe2+/Co2+摩尔比的电解液中,利用交流电化学沉积,在模板孔内成功制备了FeCo合金纳米线阵列。分别采用透射电子显微镜(TEM),场发射扫描电子显微镜(FE-SEM),X射线衍射仪(XRD)和震动样品磁强计(VSM)对样品的形貌,结构及磁学性能进行了表征。结果表明,制备的FeCo合金纳米线排列有序,粗细均匀;其直径与模板孔径一致,填充率较高,且具有明显的[110]择优取向。VSM测试结果表明,不同溶液浓度下制备的FeCo合金纳米线阵列均具有良好的垂直磁各向异性,易磁化轴沿着纳米线轴线方向。随着电解液Fe2+/Co2+摩尔比的不同,可在一定范围内对FeCo合金纳米线阵列的磁性进行调控,并对其原因进行了讨论。     

合成和表征NiFe2O4纳米线阵列

采用真空灌注结合溶胶-凝胶和氧化铝模板法,在多孔氧化铝模板中制备了平均直径为50 nm的NiFe2O4纳米线阵列.X射线衍射结果显示所制备的纳米线是纯相的NiFe2O4纳米线,透射电镜和电子衍射的结果显示已制备的纳米线是多晶的且表面光滑,场发射扫描电镜图片显示纳米线是大面积且平行有序的、纳米线的长度和所用的氧化铝模板的厚度相当.磁测量的结果显示此纳米线阵列有形状各向异性,同块状材料相比矫顽力有所增强.对纳米线的生长机理做了简单的讨论.     

Single-crystal silver nanowires: Preparation and Surface-enhanced Raman Scattering (SERS) property

Ordered Ag nanowire arrays with high aspect ratio and high density self-supporting Ag nanowire patterns were successfully prepared using potentiostatic electrodeposition within the confined nanochannels of a commercial porous anodic aluminium oxide (AAO) template. X-ray diffraction and selected area electron diffraction analysis show that the as-synthesized samples have preferred (220) orientation. Transmission electron microscopy and scanning electron microscopy investigation reveal that large-area and ordered Ag nanowire arrays with smooth surface and uniform diameter were synthesized. Surface-enhanced Raman Scattering (SERS) spectra show that the Ag nanowire arrays as substrates have high SERS activity.     

Effect of the Electrodeposition Frequency,Wave Form,and Thermal Annealing on Magnetic Properties of [Co0.975Cr0.025]0.99Cu0.01 Nanowire Arrays

Highly ordered [Co _0.975Cr _0.025]_0.99Cu _0.01 nanowire arrays were electrodeposited by conducting alternating current (AC) conditions from sulfate-based electrolyte into nanopores of anodic aluminum oxide (AAO) template with 37 nm pore diameter and the interpore distances of almost 50 nm. Fabricated nanowire arrays were characterized using scanning electron microscopy, alternating gradient force magnetometer, and X-ray diffraction. The results illustrated that varying frequency, wave form, and annealing procedure had influence on magnetic properties of as deposited nanowires. The nanowire arrays electrodeposited at different electrodeposition frequencies show remarkably different magnetic behaviors. Due to increasing of the electrodeposition frequency, the rate of ions for reduction was decreased. The nanowires prepared at various wave form illustrated insignificant impact on magnetic properties. X-ray diffraction patterns display that both as-deposited and annealed nanowire arrays expose the same structure. The raised value of coercivity has been determined in annealed nanowire arrays. Magnetization measurements show that the maximum value of coercivity for [Co _0.975]_0.99Cu _0.01 nanowires is observed at high temperature.     

Electrochemical Fabrication of Pd-Ag Alloy Nanowire Arrays in Anodic Alumina Oxide Template

The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide （AAO） template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors. Scanning electron microscopy （SEM） and energy dispersed X-ray spectroscopy （EDX） were employed to characterize the morphologies and compositions of the Pd-Ag nanowires. X-ray diffraction （XRD） was used to characterize the phase properties of the Pd-Ag nanowires. Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V （vs SCE）. The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores. The underpotential deposition of Ag＋ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy. Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd^2＋ and Ag＋ and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.     

电化学方法制备钛(Ⅳ)化合物纳米丝阵列

采用直流和脉冲电沉积法在阳极氧化多孔氧化铝薄膜的孔隙中制备了钛化合物纳米丝阵列。通过扫描电子显微镜、循环伏安曲线等手段研究了沉积条件如电子信号和电压等对所制备的纳米丝密度的影响。结果表明,应用脉冲电沉积法可制备致密的钛化合物阵列。     

Synthesis and characterisation of γ-Fe2O3 nanowire arrays via a versatile,simple and low-cost method

γ-Fe₂O₃ nanowire arrays embedded in anodic alumina template were fabricated by an improved sol–gel method. The morphologies, structures and magnetic behaviour of the as-prepared products were investigated by X-ray powder diffraction, transmission electron microscopy, selected area electron diffraction, field emission scanning electron microscopy and magnetic hysteresis analysis. The results show that arrayed γ-Fe₂O₃ polycrystalline nanowires with an average diameter about 40?nm and an average length about 0.5?µm were prepared. A number of superparamagnetic nanoneedles grew along the nanowires. The ordered one-dimensional arrays weaken the superparamagnetic effect. In addition, a possible formation mechanism about nanowires is proposed. The charge factor, gravity effect and molecular heat movement impelled the Fe sols filling into the pores of the template. γ-Fe₂O₃ nanowire arrays look forward to the applications of magnetic recording in the future.     

Electrochemical fabrication of ordered Ag2S nanowire arrays

We have successfully fabricated ordered crystalline Ag₂S nanowire arrays by direct current electrodeposition into the nanochannels of porous anodic aluminum oxide templates from a dimethylsulfoxide solution containing AgNO₃ and elemental S. X-ray diffraction and the selected area electron diffraction investigations demonstrate that the Ag₂S nanowires are a uniform actanthite structure. Electromicroscopy results show that the nanowires are quite ordered with diameters of about 40 nm and lengths up to 5 μm. X-ray energy dispersion analysis indicates that the atomic composition of Ag and S is very close to a 2:1 stoichiometry. Furthermore, a possible mechanism for the formation of the Ag₂S nanowires is proposed.     

Patterned procedure for template-synthesis and microstructural characterization of copper nanowires

Highly ordered circular patterns of copper nanowire arrays were successfully deposited into designed anodic aluminum oxide templates. High-resolution transmission electron microscopy was used to study the microstructure of these Cu nanostructures. The results showed that the growth orientation of the copper nanowires was along [220] direction, and the broken orientation were along [2?02?] and [02?2] directions, respectively. Regular cones were formed at the broken end of nanowires. Bent nanowires were also observed, this means that the copper nanowires have good mechanical properties when applied external force. Chemical analysis has been performed on Cu nanowires using electron energy-loss spectroscopy.     

Tailoring coercivity and magnetic anisotropy of Co nanowire arrays by microstructure

To tailor coercivity and magnetic anisotropy, we have fabricated Co nanowire arrays in the pores of anodic aluminum oxide templates by electrodeposition. Microstructure measurements performed by X-ray diffraction show that Co nanowire arrays are hexagonal close-packed (HCP) structures with different crystalline textures. A wide range in change of coercivity from 925 to 3310 Oe at 300 K, with a maximum of up to 4050 Oe at 5 K, can be found for nanowire arrays with a diameter of 20 nm. This may be the highest value and the widest range of coercivity reported for Co nanowires prepared by electrodeposition method. This finding could be attributed to the adjustment of the microstructure of the cobalt nanowire arrays prepared in different experimental conditions. We have also investigated the relationship between the crystalline textures and the magnetic properties of Co nanowire arrays using micromagnetic simulation combined with microstructure measurements. The preferred orientation of nanowire arrays, such as (1000) or (0002), is a key factor in determining coercivity. This wide tailoring of coercivity makes possible more promising applications of Co nanowire arrays with fixed diameter and length.     

氧化锌纳米线/管阵列的溶胶-凝胶模板法制备与表征

用溶胶-凝胶法在氧化铝模板中制备了直径约为15、30、50、60nm的有序氧化锌纳米线/管阵列.用扫描电镜(SEM)、透射电镜(TEM)和X射线衍射仪(XRD)对氧化锌纳米线/管的形貌、结构以及相组成进行了分析.结果发现,纳米线的形貌依赖于氧化铝模板中孔洞的形貌,纳米线的长度受控于氧化铝模板的厚度,外径与氧化铝模板的孔径相等.通过控制溶胶的浓度以及氧化铝模板在溶胶中的浸泡时间可以制备出纳米管.     

非晶Co及CoP纳米阵列的制备及研究

采用交流电化学沉积法,在多孔阳极氧化铝(AAO)模板孔洞中成功制备出直径50nm的Co纳米线阵列.采用透射电子显微镜(TEM)和选区电子衍射(SAED)观察了样品的微观形貌结构.结果显示,阵列中纳米线均匀有序,形状各向异性较大,其晶体结构为非晶.在沉积Co纳米线阵列的电解液中添加一定的还原剂(NaH2PO2·H2O),制备出非晶CoP纳米阵列,由TEM观察可知,阵列形貌发生变化,沉积产物为离散的纳米粒子而非纳米线.探讨了交流电沉积纳米阵列的生长机理.