CuO纳米线的制备及电子发射性能的研究

采用热氧化法成功制备大小均匀的CuO纳米线,采用扫描电子显微镜(SEM)和X射线衍射(XRD)分别表征其形貌和晶体结构,研究了温度对其形貌和结构的影响,并针对其生长机理进行探讨。场致电子发射测试表明,CuO纳米线具有较好的电子发射特性:其开启电场强度为3.75V/μm,电流密度可达0.33mA/cm~2。CuO纳米线有望作为冷阴极材料在场致发射器件上得到应用。     

CuO/ZnO复合纳米树阵列的制备及光学特性

通过热氧化法在铜基板上制备CuO纳米线,采用凝胶法制备ZnO/CuO复合纳米树阵列。通过扫描电镜(SEM)、X射线衍射(XRD)、光致发射光谱对样品结构、形貌、光学特性进行表征。结果表明,CuO/ZnO纳米树形貌规整完美,在CuO纳米线上二次生长的ZnO纳米棒具有各向晶体生长性质,CuO/ZnO复合纳米树在可见光区域出现了优越的发光性能;以甲基橙为模拟污染物,通过光催化测试表明,CuO/ZnO复合纳米树还具有卓越的光催化性能。     

水热法在碳纤维表面生长ZnO纳米线及性能研究

采用水热法在碳纤维表面生长ZnO纳米线,通过扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和SmileView软件对ZnO纳米线进行分析。XPS结果确认碳纤维表面纳米线为ZnO纳米线,SEM图片说明T700碳纤维表面ZnO纳米线取向度高于T300碳纤维表面ZnO纳米线,关于生长时间的分析表明最优值为4h。此外,通过附着生长在碳纤维表面制备了改性的ZnO纳米线,XPS测试结果表明ZnO纳米线表面涂层为CoO。     

SOI基上制备CuO纳米线

在SOI基上制备光电纳米器件具有良好的光电集成应用前景,通过铜膜生长法在SOI基上制备了形貌为类针状的Cu(OH)2前驱体纳米线,并采用热处理法600℃条件下成功制备了CuO纳米线。通过扫描电镜(SEM)、透射电镜(TEM)、X射线衍射测试(XRD)对样品结构、形貌进行了表征。SEM、TEM测试结果表明,Cu(OH)2前驱体纳米线结构一致,尺寸均匀,表面光滑。在Cu(OH)2前驱体纳米线上二次生长的CuO纳米线具有类蒲草状细长光滑的结构,CuO纳米线直径约为80~100nm,长度约为10μm,CuO纳米线结晶性良好。     

不同温度和时间对SMAT黄铜基底生长ZnO纳米结构与形貌的影响

利用热氧化法,在不同氧化温度、保温时间条件下,在经过SMAT处理的Cu-Zn合金基底上生长出ZnO纳米线。采用X射线衍射、扫描电子显微镜、高分辨透射电子显微镜对样品结构、形貌进行了分析表征。结果表明:表面生长的纳米线为六方结构ZnO;氧化温度、保温时间对ZnO纳米线形貌有较大影响。总结了纳米线的生长机理。     

不同温度和时间对SMAT黄铜基底生长ZnO纳米结构与形貌的影响

利用热氧化法，在不同氧化温度、保温时间条件下，在经过SMAT处理的Cu—Zn合金基底上生长出ZnO纳米线。采用X射线衍射、扫描电子显微镜、高分辨透射电子显微镜对样品结构、形貌进行了分析表征。结果表明：表面生长的纳米线为六方结构ZnO；氧化温度、保温时间对ZnO纳米线形貌有较大影响。总结了纳米线的生长机理。     

三维网络结构氧化铜纳米线锂离子电池负极材料的制备和性能研究

通过阳极氧化法和后退火处理在铜箔上合成了三维网络结构氧化铜纳米线,将其作为负极材料制备了无需添加粘结剂的锂离子电池。研究了恒压氧化时间对材料形貌和电化学性能的影响。在1C的倍率下,氧化1000 s制备的CuO纳米线表现出最高的1172 mAh/g首圈放电比容量和594 mAh/g的可逆比容量,500圈循环可逆比容量为607.6 mAh/g,可逆容量保留率为102.3%。交联的三维网络结构CuO纳米线相互支撑,提供稳定的结构,有效缓解了CuO纳米线作为锂离子电池负极材料中的体积膨胀问题,表现出了优异的倍率性能和循环寿命。     

针尖状SiC纳米线的合成与机理分析

采用热蒸发硅的方法,于1650℃反应不同的时间,在聚丙烯腈(PAN)碳纤维上原位生长碳化硅纳米线。通过X射线衍射,场发射扫描电镜及透射电子显微镜分析和观察,发现制得的产物为β-SiC单晶纳米线,具有明显的针尖状头部,且呈放射状生长在碳纤维上,形成试管刷状阵列。基于在反应不同阶段所得到产物的不同形貌,结合对制备条件和制备原料的分析,提出不同于传统VLS机理的VL’S机理。     

退火温度对电沉积FeNi纳米线阵列结构及磁性能的关联性研究

采用E-T和脉冲电化学沉积法,利用氧化铝（AAO）模板制备出直径200 nm,长度约为13.1μm的非晶态FeNi纳米线阵列。FeNi纳米线阵列的形貌、成分、微观结构以及磁学性能分别通过场发射扫描电子显微镜（SEM）、场发射透射电子显微镜（TEM）、X射线衍射仪（XRD）以及振动样品磁强计（VSM）进行表征。研究结果表明,FeNi纳米线排列致密,外壁平整光滑,粗细均匀,元素分布均匀。制备的纳米线表现出纯非晶结构,退火后从非晶基体中析出γ（Fe, Ni）相,且晶粒的生长具有明显的（111）择优取向。VSM结果表明在非晶纳米线中具有较强的磁各向异性,其易磁化轴为平行于长轴方向。随着退火温度的升高,矫顽力H_c和剩磁比B_r/B_s整体呈下降趋势,主要归因于纳米线内应力的释放及纳米晶间的磁交换耦合作用。     

交流电沉积制备SnO2纳米线及其电沉积条件研究

采用阳极氧化的方法制备了孔径为30～50nm多孔阳极氧化铝(AAO)模板,用交流(AC)电沉积法在氧化铝模板孔洞内沉积金属锡,然后在空气中750℃加热含锡的模板10h,热氧化制备了直径在30～50nm SnO2纳米线．用扫描电子显微镜,透射电子显微镜,X射线衍射仪对所制备的SnO2纳米线进行了表征,表明所制备的纳米线为多晶结构．并通过改变交流电沉积过程中的电压,频率和热氧化时间来考察不同沉积条件对沉积结果的影响,发现采用交流沉积制备金属纳米线的过程中,频率和电压是影响沉积结果的关键因素．     

Controlled growth of CuO nanowires on woven carbon fibers and effects on the mechanical properties of woven carbon fiber/polyester composites

The effect of CuO nanowires on the improvement of the mechanical properties of woven carbon fiber (WCF)-based polyester resin composite was studied. The composite was manufactured by the vacuum-assisted resin transfer molding (VARTM) process. CuO nanowires were grown on woven carbon fiber sheets in subsequent steps of seeding followed by growth. Scanning electron microscopy (SEM) showed the growth of CuO nanowires on the surface of the carbon fibers; this growth increased with the number of seeding cycles and the length of the growth time. The concentration of the growth solution did not have a significant effect. The maximum amount of growth occurred for 8 seeding cycles with a 60 mM growth solution and a growth time of 8 h. An analysis of the percent weight change, along with X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, supported the above findings. The crystalline peak height of the CuO nanowires increased with the nanowire growth. The new absorption peaks arising in the FTIR spectra also indicated growth of CuO nanowires on the WCF. The mechanical properties in terms of tensile strength, modulus, and impact resistance improved significantly after the growth of nanowires on the carbon fibers: the modulus and strength improved by up to 33.1% and 42.8%, while the impact energy absorption increased by 136.8% relative to bare WCF.     

Transition metal oxide nanowires synthesized by heating metal substrates

Here we reported a simple method to synthesize transition metal oxide nanowires. Copper oxide (CuO), zinc oxide (ZnO), and cobalt oxide (Co₃O₄) nanowires were synthesized by heating the copper, zinc, and cobalt substrates under atmosphere condition. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the morphology and microstructure of the nanowires. According to our experimental results, self-catalysis growth mechanism was proposed to explain the growth of the nanowires. The temperature window for the growth of nanowires was estimated by taking into account the Gibbs free energy of reaction. The synthesis approach observed in our experiment could be applied to synthesize other one-dimensional structures, such as FeSe and Bi₂Te₃ nanowires.     

Ferromagnetic behavior of copper oxide-nanowire-covered carbon fibre synthesized by thermal oxidation

Copper oxide nanowires were synthesized on carbon fibre surfaces by annealing of copper thin films at 400 °C for 4 h in air. The nanowires were characterized with field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The magnetic properties of CuO nanowires were measured with a vibrating sample magnetometer (VSM). Its diameters range covered 40–100 nm and lengths range covered 1–3 μm. It is interesting that the CuO nanowires on the carbon fibres showed ferromagnetism at room temperature.     

Synthesis and characterization of Y-shaped carbon fibers by chemical vapor deposition

In this work, Y-shaped carbon fibers with high purity were successfully synthesized by CVD using copper tartrate as a catalyst precursor at low reaction temperature, 279 °C. A model has been proposed for interpreting the mechanism of the Y-shaped carbon fibers growth. It is suggested that the introduction of hydrogen is the key factor to the formation of three carbon fibers growth faces on every the agglomeration of copper monocrystalline catalyst particles and lead to the formation of Y-shaped carbon fibers subsequently. The Y-shaped carbon fibers were characterized by field emission scanning electron microscopy, transmission electron microscopy and X-ray diffraction.     

Synthesis of SiC nanowires with in-situ deposition of carbon coating

SiC nanowires are effective reinforcement materials in ceramic matrix composites. A compliant coating such as carbon on nanowires is necessary in order to moderate the nanowire/matrix interfacial bounding for taking the most advantages of SiC nanowires. SiC nanowires with an in-situ deposition of carbon shell coating were fabricated by a novel chemical vapor growth process. Highresolution transmission electron microscopy examinations showed that the nanowires consisted of a single crystal beta-SiC core with an amorphous carbon shell 2-5 nm in thickness. The nanowires were straight with a length generally over 10 microm and a diameter 15-150 nm. The growth direction of the core SiC nanowires is (111). A simple three-step growth model for SiC nanowires was proposed based on a vapor-solid growth mechanism. Because the carbon-coated nanowires were grown directly on continuous Tyranno-SA SiC fibers, in-situ application of the present technique on the fabrication of SiC nanowire-reinforced SiC/SiC composites is expected.     

Synthesis of the tube-brush-shaped SiC nanowire array on carbon fiber and its photoluminescence properties

Tube-brush-shaped nanostructure of SiC nanowires was synthesized on polyacrylonitrile-based carbon fibers. The morphology and microstructure of the nanowires were characterized by X-ray powder diffraction, field emission scanning electron microscopy and high-resolution transmission electron microscopy. A quasi-periodically twin structure with (111) plane as the boundary along the SiC nanowires was observed. The vapor-solid growth mechanism of the SiC nanowire brush is also discussed. Moreover, some separated blue-shifted photoluminescence peaks around 469 nm were measured. The separated blue-shifted emission peaks are attributed to the quantum confinement of nanoscaled twin segments along each nanowire rather than the apparent diameters of the nanowires. The SiC nanowire brushes hopefully can find potential applications in nanotechnology.     

Low temperature synthesis of seed mediated CuO bundle of nanowires,their structural characterisation and cholesterol detection

In this study, we have successfully synthesised CuO bundle of nanowires using simple, cheap and low temperature hydrothermal growth method. The growth parameters such as precursor concentration and time for duration of growth were optimised. The field emission scanning electron microscopy (FESEM) has demonstrated that the CuO bundles of nanowires are highly dense, uniform and perpendicularly oriented to the substrate. The high resolution transmission electron microscopy (HRTEM) has demonstrated that the CuO nanostructures consist of bundle of nanowires and their growth pattern is along the [010] direction. The X-ray diffraction (XRD) technique described that CuO bundle of nanowires possess the monoclinic crystal phase. The surface and chemical composition analyses were carried out with X-ray photoelectron spectroscopy (XPS) technique and the obtained results suggested the pure crystal state of CuO nanostructures. In addition, the CuO nanowires were used for the cholesterol sensing application by immobilising the cholesterol oxidase through electrostatic attraction. The infrared reflection absorption spectroscopy study has also revealed that CuO nanostructures are consisting of only CuO bonding and has also shown the possible interaction of cholesterol oxidase with the sharp edge surface of CuO bundle of nanowires. The proposed cholesterol sensor has demonstrated the wide range of detection of cholesterol with good sensitivity of 33.88 ± 0.96 mV/decade. Moreover, the CuO bundle of nanowires based sensor electrode has revealed good repeatability, reproducibility, stability, selectivity and a fast response time of less than 10 s. The cholesterol sensor based on the immobilised cholesterol oxidase has good potential applicability for the determination of cholesterol from the human serum and other biological samples.     

Direct growth of oxide nanowires on CuOx thin film

Oxide nanowires were directly grown on a CuO(x) thin film deposited by plasma-enhanced atomic layer deposition without additional metal catalysts. Oxide nanowires would exhibit metal-catalyst-free growth on the CuO(x) thin film with oxide materials diffused on the top. Through a focused ion beam and transmission electron microscopy, we could verify that SnO(2) and ZnO nanowires were grown as single-crystalline structures just above the CuO(x) thin film. Bottom-gate structural SnO(2) and ZnO nanowire transistors exhibited mobilities of 135.2 and 237.6 cm(2) V(-1) s(-1), respectively. We anticipate that a variety of large-area and high-density oxide nanowires can be grown at low cost by using the CuO(x) thin film.     

Controlled synthesis of CuO nanostructures on Cu foil, rod and grid

CuO nanowires are synthesized by heating Cu foil, rod and grid in ambient without employing a catalyst or gas flow at temperatures ranging from 400 to 800 °C for a duration of 1-12 h. Scanning electron microscopy (SEM) investigation reveals the formation of nanowires. The structure, morphology and phase of the as-synthesized nanowires are analyzed by various techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). It is found that these nanowires are composed of CuO phase and the underlying film is of Cu₂O. A systematic study is carried out to find the possibilities for the transformation of one phase to another completely. A possible growth mechanism for the nanowires is also discussed.     

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.