铁纳米线阵列的制备及磁性质

使用电化学沉积方法，在有序的氧化铝模板（AAO）孔洞中制备了铁纳米线有序阵列．用X射线衍射仪（XRD）、场发射扫描电子显微镜（FE-SEM）、透射电子显微镜（TEM）、对样品的结构、形貌、进行表征和观测．XRD的结果表明所制备的样品为纯的立方面心铁．SEM的图片清晰地说明铁纳米线阵列是大面积、高填充率和高度有序的．TEM的结果显示纳米线直径均匀、表面光滑且长径比大．磁测量的结果表明纳米线阵列的易磁化轴是垂直于模板表面的。     

液相电沉积技术制备n-型铋碲纳米线阵列温差电材料

对铋碲合金电沉积过程进行了研究,并分析了温度和硝酸浓度对铋碲共沉积的影响.结果表明,Bi³⁺和HTeO₂⁺合溶液中的电沉积是分阶段进行的.溶液中HTeO₂⁺的存在阻碍了Bi³⁺的电沉积.铋碲共沉积的速度随温度的升高以及溶液中硝酸浓度的增加而加速.实验中还研究了沉积电位对铋碲组成的影响.采用ESEM分析了铋碲纳米线阵列温差电材料的形貌.     

铜纳米线阵列的模板组装

采用电解法溶解多孔阳极氧化铝(PAA)模板的阻挡层,用直流电沉积的方法在模板中组装了铜纳米线阵列.分别用扫描电镜和X射线衍射表征铜纳米线阵列的形貌和晶体结构,用电化学法表征了铜纳米线阵列的电催化性能.结果表明,PAA去阻挡层后,伏安图上出现一个阳极氧化峰.恒电位沉积的铜纳米线直径为22nm,沿(111)晶面择优取向.铜纳米线阵列电极能催化亚硝酸根的还原,其催化电流比本体铜电极上大2倍,峰电位正移80mV.纳米铜阵列电极可用于亚硝酸盐的电化学检测.     

CuS纳米线阵列的制备

将多孔阳极氧化铝模板(AAO)的电化学沉积技术与真空硫化技术相结合,在制备Cu纳米线的基础之上,制备得到了CuS纳米线阵列.采用扫描电子显微镜电镜和X射线衍射仪对二次氧化的AAO模板和所得Cu与CuS纳米线的形貌和结构进行了表征,结果表明所得CuS纳米线不仅具有良好的有序阵列,而且具有多晶结构.在硫化过程中,随着硫化温度的升高,CuS结晶程度增大,在500～550℃时,达到最大的结晶程度.     

铜纳米线阵列显微结构的表征和控制

采用多孔氧化铝(AAO)模板脉冲电沉积法制备了强辐射源用铜纳米线阵列材料,并用扫描电子显微镜(SEM)、能谱(EDS)和X射线衍射(XRD)对其进行了结构袁征.结果表明电沉积的峰值电流强度和辅助阴极可以影响铜纳米线的表面质量、长度分布均匀性和微区长度起伏.减小峰值电流强度,可以明显改善单根铜纳米线的表面质量,但是对铜纳...     

交流电化学沉积铜纳米线阵列及其机理探讨

利用二次阳极氧化的方法制备孔高度有序的阳极氧化铝(AAO)为模板,采用交流电化学沉积方法,在AAO模板孔道内制备Cu纳米线。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线衍射仪(XRD)对Cu纳米线的形貌、晶体结构进行研究。结果表明:模板的孔径均匀,孔道平直。Cu纳米线均匀分布在AAO模板纳米孔隙中,直径均一,并沿Cu(Ⅲ)晶面择优生长;AAO模板孔道生长铜纳米线不光滑,成凹凸状,并对此沉积机理进行探讨。     

不同结构镍纳米线阵列的制备及其磁性

采用直流电沉积在多孔有序氧化铝模板中制备了不同结构的有序镍纳米线阵列。采用SEM和TEM对所制备的镍纳米线的形貌和结构进行了表征。研究了镍纳米线不同结构对镍纳米线阵列磁性性能的影响规律．当电沉积电压为2．5V时制备的镍纳米线为多晶结构；电沉积电压4V时，镍纳米线为沿[220]择优取向的单晶结构；电沉积电压＞5V时，择优取向由[220]转为[111]方向．磁滞回线结果表明，单晶镍纳米线阵列与多晶纳米线阵列相比具有更高的矩形度，沿[111]择优取向的单晶纳米线相比沿[220]取向的单晶镍纳米线具有更大的矩形度，表现出显著的磁各向异性。     

TiO2纳米线阵列生长机理的研究

采用两步氧化法制备了多孔氧化铝模板(AAO),并利用AAO结合用电化学诱导溶胶-凝胶法制备了锐钛矿型的TiO2纳米线阵列,探讨了形成TiO2纳米线阵列的生长机理.发现TiO2纳米线是由Au基底沿着孔洞逐步向上生长,直接生成纳米线,因而可以通过控制氧化铝模板的尺寸和电化学沉积的时间来控制纳米线的长径比.     

CdS纳米线阵列光致发光的研究

用直流电沉积法在多孔氧化铝模板中制备了高度有序的CdS纳米线阵列,SEM和XRD的观察和测量表明,CdS纳米线尺寸均匀、排列规整,具有六方纤锌矿结构,Cd和S的化学计量比为11.CdS纳米线阵列的光致发光测量显示,激发波长为325nm时,CdS纳米线阵列在450nm处有一强的PL峰,在484nm处还有一肩峰.对其光致发光机理进行了分析.     

Synthesis and characterization of single crystalline selenium nanowire arrays

Ordered selenium nanowire arrays with diameters about 40 nm have been fabricated by electrodeposition using anodic porous alumina templates. As determined by X-ray diffraction, Raman spectra, electron diffraction and high-resolution transmission electron microscopy, selenium nanowires have uniform diameters, which are fully controllable. Single crystalline trigonal selenium nanowires have been obtained after postannealing at 180 °C. These nanowires are perfect with a c-axis growth orientation. The optical absorption spectra reveal two types of electron transition activity.     

Electrodeposited bismuth telluride nanowire arrays with uniform growth fronts

Bismuth telluride (Bi2Te3) nanowires were deposited into porous alumina templates with 35 nm diameter pores by a pulsed-potential electrodeposition method. For growth at temperatures between 1 and 4 degrees C, the nanowires filled 93% of the pores of the template, and the growth fronts were uniform with nanowire lengths of approximately 62-68 microm. There are over ten billion nanowires per square centimeter with aspect ratios approaching 2000:1. Samples were characterized by scanning and transmission electron microscopy, X-ray diffraction, and electron microprobe analysis. The crystalline nanowire arrays are highly oriented in the [110] direction, which is optimal for thermoelectric applications.     

Controlled growth of Si nanowire arrays for device integration

Silicon nanowires were synthesized, in a controlled manner, for their practical integration into devices. Gold colloids were used for nanowire synthesis by the vapor-liquid-solid growth mechanism. Using SiCl4 as the precursor gas in a chemical vapor deposition system, nanowire arrays were grown vertically aligned with respect to the substrate. By manipulating the colloid deposition on the substrate, highly controlled growth of aligned silicon nanowires was achieved. Nanowire arrays were synthesized with narrow size distributions dictated by the seeding colloids and with average diameters down to 39 nm. The density of wire growth was successfully varied from approximately 0.1-1.8 wires/microm2. Patterned deposition of the colloids led to confinement of the vertical nanowire growth to selected regions. In addition, Si nanowires were grown directly into microchannels to demonstrate the flexibility of the deposition technique. By controlling various aspects of nanowire growth, these methods will enable their efficient and economical incorporation into devices.     

Synthesis, structure and photoelectrochemical properties of single crystalline silicon nanowire arrays

In the present work, n-type silicon nanowire (n-SiNW) arrays have been synthesized by self-assembly electroless metal deposition (EMD) nanoelectrochemistry. The synthesized n-SiNW arrays have been submitted to scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and optical studies. Initial probes of the solar device conversion properties and the photovoltaic parameters such as short-circuit current, open-circuit potential, and fill factor of the n-SiNW arrays have been explored using a liquid-junction in a photoelectrochemical (PEC) system under white light. Moreover, a direct comparison between the PEC performance of a polished n-Si(100) and the synthesized n-SiNW array photoelectrodes has been done. The PEC performance was significantly enhanced on the n-SiNWs photoelectrodes compared with that on polished n-Si(100).     

ZnO纳米线阵列的图形化生长

采用光刻和射频磁控溅射技术在Si衬底上制备了图形化的ZnO种子层薄膜。分别采用气相榆运和水热合成法，制备了最小单元为30μm的图形化的ZnO纳米线阵列。X射线衍射（XRD）分析显示单晶纳米线阵列具有高度的c轴[001]择优取向生长性质，从扫描电子显微镜（SEM）照片看出，阵列图形完整清晰，边缘整齐，纳米线阵列在室温下光致发光（PL）谱线中在380hm左右具有强烈的紫外发射峰，可见光区域发射峰得到了抑制，证明ZnO纳米线阵列氧空位缺陷少，晶体质量高。     

Ag-assisted CBE growth of ordered InSb nanowire arrays

We present growth studies of InSb nanowires grown directly on [Formula: see text] and [Formula: see text] substrates. The nanowires were synthesized in a chemical beam epitaxy (CBE) system and are of cubic zinc blende structure. To initiate nanowire nucleation we used lithographically positioned silver (Ag) seed particles. Up to 87% of the nanowires nucleate at the lithographically pre-defined positions. Transmission electron microscopy (TEM) investigations furthermore showed that, typically, a parasitic InSb thin film forms on the substrates. This thin film is more pronounced for InSb((111)B) substrates than for InAs((111)B) substrates, where it is completely absent at low growth temperatures. Thus, using InAs((111)B) substrates and growth temperatures below 360?°C free-standing InSb nanowires can be synthesized.     

Controlled fabrication and electrical properties of long quasi-one-dimensional superconducting nanowire arrays

We report a general method for reliably fabricating quasi-one-dimensional superconducting nanowire arrays, with good control over nanowire cross section and length, and with full compatibility with device processing methods. We investigate Nb nanowires with individual nanowire cross sectional areas that range from bulklike to 10 x 11 nm, and with lengths from 1 to 100 microm. Nanowire size effects are systematically studied. In particular, a comprehensive investigation of influence of nanowire length on superconductivity is reported for the first time. All results are interpreted within the context of phase-slip models.     

Controlled in situ nanoscale enhancement of gold nanowire arrays with plasmonics

The controlled in situ growth of ordered gold nanoparticles and nanowire arrays has been studied by optically tracking changes in the local surface plasmon resonance (LSPR) spectrum. A spectrometer and custom-programmed analysis software track changes in the LSPR spectrum. The peak position, peak height (i.e. extinction intensity) and peak width (e.g. radius of curvature) were tracked over time to quantify the dynamic growth of gold as soon as the system was exposed to a commercial gold enhancement solution. This enables the controlled dynamic growth of nano-objects without the necessity of characterizing the growth and aggregation kinetics of the gold enhancement solution. The result was the successful enhancement of their electrically conductive and plasmonic properties, as well as the controlled growth and transformation of line-patterned nanoparticles into conductive particle-based nanowires.     

p-Type ZnO nanowire arrays

Well-aligned ZnO nanowire (NW) arrays with durable and reproducible p-type conductivity were synthesized on alpha-sapphire substrates by using N2O as a dopant source via vapor-liquid-solid growth. The nitrogen-doped ZnO NWs are single-crystalline and grown predominantly along the [110] direction, in contrast to the [001] direction of undoped ZnO NWs. Electrical transport measurements reveal that the nondoped ZnO NWs exhibit n-type conductivity, whereas the nitrogen-doped ZnO NWs show compensated highly resistive n-type and finally p-type conductivity upon increasing N2O ratio in the reaction atmosphere. The electrical properties of p-type ZnO NWs are stable and reproducible with a hole concentration of (1-2) x 10(18) cm(-3) and a field-effect mobility of 10-17 cm2 V(-2) s(-1). Surface adsorptions have a significant effect on the transport properties of NWs. Temperature-dependent PL spectra of N-doped ZnO NWs show acceptor-bound-exciton emission, which corroborates the p-type conductivity. The realization of p-type ZnO NWs with durable and controlled transport properties is important for fabrication of nanoscale electronic and optoelectronic devices.