多孔氧化铝模板制备ZnS纳米线阵列及其光致发光谱

利用阳极氧化铝（AAO）模板,采用电化学沉积方法制备出了ZnS纳米线阵列。扫描电子显微镜（SEM）结果显示,AAO模板孔洞分布均匀,孔径基本一致（约50nm）,孔口呈六边形。TEM结果显示硫化锌纳米线的直径约50nm（与AAM模板孔径一致）,长度约为20μm（与AAM模板厚度一致）。电子衍射结果表明ZnS纳米线为多晶结构。比较了AAO模板组装ZnS纳米线阵列前后的光致发光谱,所得光谱显示,组装了ZnS纳米线阵列的模板的光致发光谱比没有组装的空模板相比多出两个发射峰,分别位于409,430nm,且其发光强度随激发波长的增长而增强。解谱分析表明,这即为ZnS纳米线阵列的发光光谱的两个发射峰,是由导带与受主能级间的跃迁发光和施主与受主能级间的复合跃迁发光共同作用所致。发现由于纳米线尺寸的单一性,发射峰窄化明显,半峰全宽较小,这种现象在其他文献中未曾报道过。     

不同制备条件对聚偏氟乙烯纳米线生长的影响

为提高铁电聚合物聚偏氟乙烯(PVDF)的压电性能,利用纳米限域效应,采用模板直接浸润法,将多孔氧化铝(AAO)模板在不同浓度的PVDF的DMF溶液中自然浸润,并添加聚乙烯吡咯烷酮(PVP)作为表面修饰剂,制备了一维材料PVDF纳米线。分别研究了浸润温度、溶液浓度及表面修饰剂等因素对PVDF纳米线生长过程的影响。通过FTIR、SEM、XRD等对样品的形貌结构及性能进行了表征,进一步讨论了AAO模板中PVDF纳米线的生长机制。结果表明:模板法生长的PVDF纳米线形貌主要受溶液浓度的影响,并且当浓度为0.10 g/m L时形貌较优,其平均长度为50μm,平均直径为180 nm,与AAO模板孔径尺寸相当;表面修饰剂PVP可在一定程度上防止纳米线团聚并且优化其尺寸均一性;AAO模板中生长的PVDF纳米线由于纳米限域效应优先向β晶相结晶,并且在生长过程中PVDF并未参与任何化学反应。     

AlN纳米线宏观阵列的制备

借助二次模板法成功的合成了AlN纳米线宏观阵列,并进行了表征.主要研究CVD法制备有一定取向,直径均匀的AlN纳米线宏观阵列的过程.通过气相沉积法和利用PS球自组装模板制备了金属纳米颗粒模板;再以模板上的金属纳米颗粒作为催化剂,利用化学气相沉积在模板上合成AlN纳米线宏观阵列.借助SEM,TEM观察所得样品,AlN纳米线阵列面积约为0.3 mm×0.2 mm,直径和长度分布均匀,平均直径约为41 nm,平均长度为1.8 μm左右,分散密度和覆盖率大的六角结构AlN纳米线宏观阵列.得到了可控制备AlN纳米线 关键词： AlN纳米线阵列 模板法 CVD法 SEM     

非晶碳氧化硅纳米线的合成与光致发光

利用直流电弧放电合成非晶碳氧化硅(SiCO)纳米线,不使用催化剂和模板,独立的SiCO 纳米线沉积在石墨锅的表面．通过XRD、SEM、TEM、XPS、FTIR等对SiCO纳米线进行了表征．结果表明,纳米线长度为20～100 μm,直径为10～100 nm,Si原子同C原子和氧原子分享成键组成SiCO单元．SiCO纳米线的光致发光谱在454和540 nm呈现了强而稳定的白色发光峰． SiCO纳米线的生长机制为等离子辅助气―固生长机制．     

超短超强激光与铜靶相互作用产生Kα源的蒙特卡罗模拟

超短超强激光打靶产生的超热电子,与固体靶相互作用时会产生Kα线辐射.由经典定标律给出了法线方向超热电子的温度.利用蒙特卡罗方法,对超热电子在固体靶中的传输进行了研究,模拟了不同靶厚度情况下Kα产额和角分布及不同电子温度下Kα光子的转化效率.计算结果与实验符合较好.结果表明:在一定电子温度下,随着靶厚度的增加Kα光子产额会达到饱和,并会使Kα光子发射的各向异性变得更加严重;存在最佳的电子温度,使Kα线转化效率最高.     

超强激光与Ar团簇相互作用中X射线的研究

本文主要研究了超强超短激光与Ar团簇相互作用过程中X射线能谱、K壳层光子产额、能量转换效率以及激光对比度对X射线光子产额的影响.实验中得到K壳层的光子产额约为1× 10¹¹/发,能量转换效率约为2.8× 10^-5．同时观测到较强预脉冲离化团簇会导致预电离,产生膨胀等离子体,然而主脉冲与膨胀的等离子体相互作用的强度较未膨胀时降低了,从而导致K壳层光子产额降低,而使用高对比度的激光能增加X射线光子产额.     

超导纳米线多光子响应特性研究

研究了超导单光子探测器器件超导纳米线的多光子响应特性.在温度3.5 K实验测量了纳米线器件直流特性和比子响应概率对多光子脉冲信号的响应特性.实验表明,器件超导转变电流随光辐照强度的增加而减小;在多光子脉冲信号下,器件响应的光子数随偏置电流减小而增加.同时基于量子光学和器件Hotspot理论半定量分析了该多光子响应的机制.     

超强激光超热电子激发的KαX射线发射研究

建立了无色散型X射线谱仪.利用SILEX-I激光装置的超强激光辐照固体物质,分别在靶前、后定量测量了Cu和Mo物质在不同激光功率密度时的X射线谱和Kα光子产额,推导了不同激光强度时的Kα X射线光子转换效率.实验发现,打靶激光能量越高,靶后出射的Kα产额越高,100μm Mo靶可获得10-5量级转换效率.     

有序银纳米线阵列的表面增强拉曼光谱研究

本文通过模板法制备了一系列不同孔径的氧化铝模板 ,并通过交流电向模板中沉积银而制成有序银纳米线阵列。以SCN- 作为探针分子 ,用H3PO4溶解模板并用共焦显微拉曼系统现场检测SERS信号。结果表明 ,SERS信号的强度随露出表面纳米线的长度的增加而变大 ,到一定程度后又逐渐减弱。这说明只有具有合适长径比的纳米线才会有最大的增强     

基于DNA模板与聚二甲基硅氧烷转移制备钯纳米线的新方法

在聚二甲基硅氧烷衬底上梳理得到DNA阵列,并以DNA为模板通过低温乙醇还原得到Pd纳米线,再通过PDMS转移技术将Pd纳米线转移至不同的衬底,这是一种制备高导电性Pd纳米线的新方法.以DNA为模板的选择性生长控制方法可以显著抑制衬底上无规Pd纳米颗粒的出现. SEM观测制备的Pd纳米线的宽度约为80 nm,连续长度可达14 μm. FESEM、XPS和TEM表征揭示出Pd纳米线是由面心立方结构的Pd纳米晶粒组成,电学测量获得的Pd纳米线的电阻率为1.59 μΩm,仅比体电阻率高约一个量级. 研究还发现通过改变反应时间和温度可以有效调控Pd纳米线的生长过程.     

Simple fabrication of hexagonally well-ordered AAO template on silicon substrate in two dimensions

In this study, thin anodic aluminum oxide (AAO) templates both on silicon substrates (AAO template/SiO₂/Si) and Ti-coated silicon substrates (AAO template/Ti/SiO₂/Si) were developed for design of magnetic, electronic and optoelectronic devices, chemical sensors and chip-scale lithium-ion rechargeable microbatteries. Two types of AAO template were prepared by using a two-step anodization procedure. The templates were characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. The obtained thin AAO templates were approximately 50 nm in diameter and 700 nm in length with 80-nm interpore distances in a relatively large area of 6 cm². A barrier layer of the AAO templates was removed by a cathodic polarization method in KCl solution for several seconds. The current–time transient during removing the alumina barrier layer of the thin AAO template and the mechanism of electrochemical dissolution of the barrier layer are given in detail.     

AFM study of gold nanowire array electrodeposited within anodic aluminum oxide template

Uniform gold nanowires were synthesized by electrodepositing the gold under a very low ac frequency in the pores of an anodic aluminum oxide (AAO) template. The surface of the Au/AAO composite is very even and appeared purplish red. Atomic force microscopy observation indicates that the template membranes we obtained have hexagonally close-packed nanochannels. The gold nanowire array is very orderly arranged after partially dissolving the aluminum oxide membrane. Gold nanowires were also characterized by transmission electron microscopy and the phase structure of the Au/AAO composite was proved by X-ray diffraction. Received: 19 April 2001 / Accepted: 28 April 2001 / Published online: 27 June 2001     

Controllable fabrication of highly ordered thin AAO template on Si substrate for electrodeposition of nanostructures

In this work, simple fabrication of hexagonally highly ordered porous anodic aluminum oxide (AAO) of Al thin film (1 μm) on Si substrate is described using two-step anodization method for electrochemical synthesis of nanostructures. In this method, the templates were prepared under the controllable conditions of the parameters, which give rise to the possibility of highly ordered nanopore arrays with a well aspect ratio. Pore widening was then fulfilled in 5 wt% phosphoric acid solution at 25 °C. The pore diameter and spacing are proportional to the applied voltage, which is due to the mechanical stress associated with the volume expansion of the aluminum during the anodization according to the mechanical stress model. Pore-widening solution adjusted the pore diameter and thinned the AAO barrier layer at room temperature under the control of etching time. As an application, Cu nanorods arrays embedded in anodic alumina (AAO) template were fabricated by dc electrodeposition. The characterization of the AAO templates and the Cu nanorods produced was made by X-ray diffraction, field emission scanning microscope, energy dispersive X-ray spectroscopy and atomic force microscope (AFM). The images of AFM show that porous AAO template under constant voltage is 40 V which presents the optimum ordering.     

Template synthesis of well-aligned titanium dioxide nanotubes

TiO₂ nanotubes of the anatase form have been synthesized by sol-gel chemical method using anodic aluminum oxide (AAO) as a template. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction were used to investigate the structure and morphology of the TiO₂ nanotubes. The results showed that TiO₂ nanotubes obtained are highly ordered and uniform. The diameter and length of the obtained nanotubes were determined by the pore size and the thickness of AAO template. It was found that through control of immersion time of AAO membrane in sol, both tubules and fibrils can be prepared. PACS 61.46.+w     

Cu/AAO纳米有序阵列复合结构的光学特性研究

用电化学方法制备了Cu/AAO纳米有序阵列复合结构,实验研究了该结构的光吸收与光致发光特性。结果表明,植入阳极氧化铝模板中Cu纳米粒子对结构的光吸收和光致发光影响非常敏感。即随着Cu沉积量的增加,致使该复合结构的吸收边大幅度红移,从近紫外至近红外其最大频移量可超过500 nm;同时还伴随使阳极氧化铝模板的光致发光峰位稍有蓝移、强度逐渐削弱直至猝灭的过程。分析了Cu纳米粒子使Cu/AAO复合结构出现上述现象的原因。     

Synthesis of ordered ZnO nanowire arrays from aqueous solution using AAO template

In this paper we report a simple method that enables the easy fabrication of ordered ZnO nanowire arrays using Anodic Aluminium Oxide (AAO) template. We have used a vacuum injection technique to fill solution into the pores of an AAO template. The AAO template has been fabricated by a two-step anodization process using 0.3 M oxalic acid (H₂C₂O₄) solution under a constant voltage of 40 V. The AAO template formed through this process has been detached from Al substrate via an anodic voltage pulse using perchloric acid (HClO₄) solution (70%). The nanowires of ZnO have been synthesized by injecting the saturated Zn(NO₃)₂ solution into the pores of the detached AAO template using a vacuum pump. The ZnO nanowires synthesized by this technique have been found dense & continuous with uniform diameter throughout the length of the wire. The structural characteristics of AAO template and ZnO nanowires have been studied by Field Emission Scanning Electron Microscope (FESEM), Atomic force microscope (AFM) and Transmission Electron Microscope (TEM).     

The fabrication of Ag nanoflake arrays via self-assembly on the surface of an anodic aluminum oxide template

Vertical-aligned Ag nanoflake arrays are fabricated on the surface of an anodic aluminum oxide (AAO) template under a hydrothermal condition for the first time. The porous surface of AAO templates and the precursor solution may play key roles in the process of fabricating Ag nanoflakes. The rim of pores can provide many active sites for nucleation and growth, and then nanoflake arrays gradually form through self-assembly of Ag on the surface of AAO membranes. The product is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and a growth mechanism of nanoflake is deduced. This work demonstrates that it is possible to make ordered nanoarrays without dissolving templates using the hydrothermal method, and this interesting Ag nanoflake arrays may provide a wider range of nanoscale applications.     

Temperature dependence of a nanoporous Pd film hydrogen sensor based on an AAO template on Si

In this study, hydrogen sensing properties of nanoporous Pd films based on Anodic Aluminium Oxide (AAO) templates grown on a silicon substrate have been investigated at various temperatures (25–100°C) and hydrogen concentrations (100–1000 ppm) to determine the temperature-sensitivity relationship. For this purpose, a hexagonally shaped AAO template of approximately 50 nm in diameter and 700 nm in length with 80 nm interpore distances was fabricated using two-step anodization of an Al film deposited on an n-type (100) oriented oxidized Si substrate. Then, the nanoporous surface of the AAO template was used as a substrate for supporting a nanoporous Pd film of an approximately thickness of 60 nm. The morphologies of the AAO template and Pd film coated on the AAO template were studied mainly by Scanning Electron Microscopy (SEM). Hydrogen sensing properties of the nanoporous Pd film were measured using a resistance transient method. It was found that the sensor response of the nanoporous Pd films on the AAO template was better than the traditional Pd thin film sensors, the sensitivity of the sensor was approximately 1.8% for 1000 ppm H₂, and the detection limit was lower than 100 ppm at room temperature. The highest sensitivity was measured at room temperature.     

Sol–gel template synthesis and characterization of LaCoO3 nanowires

Densely packed LaCoO₃ nanowires of the rare-earth perovskite-type composite oxide were synthesized within a porous anodic aluminum oxide (AAO) template by means of the sol–gel method using nitrate as raw the material and citric acid as the chelating agent. The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the LaCoO₃ nanowires possessed a uniform length and diameter, which were controlled by the thickness and the pore diameter of the applied AAO template, respectively. The results of X-ray diffraction (XRD) and the selected area electron diffraction (SAED) indicated that the LaCoO₃ nanowires had a rhombohedral perovskite-type crystal structure. Furthermore, X-ray photoelectron spectroscopy (XPS) demonstrated that LaCoO₃ nanowires were formed. Finally, the formation mechanism of nanowires was also discussed. PACS 61.66.Fn; 61.46.-W; 81.20.Fw     

金属铜纳米孔洞阵列膜制备方法研究

以多孔阳极氧化铝膜(anodic aluminum oxide，AAO)为模板，用真空蒸镀法复制了金属铜的纳米孔洞阵列膜，SEM结果表明，制备得到的金属铜纳米孔洞阵列膜形貌与AAO膜一致.此方法简单易行，能大规模生产，为纳米膜的工业化复制提供了一种新的工艺，为纳米线、纳米管等纳米阵列材料的合成与组装提供了有利的条件. 关键词： AAO模板 真空蒸镀 金属铜纳米孔洞阵列膜 纳米复制