化学镀制备镍纳米线/管阵列铂钯催化剂载体

以阳极氧化铝作为模板,用化学镀的方法制备了可以用作铂钯复合催化剂载体的镍纳米线和纳米管阵列,利用置换反应将铂钯复合催化剂沉积在镍纳米阵列材料上．SEM图片表明镍纳米线的平均直径 为100 nm,镍纳米管的平均内径为20 nm． EDS扫描的结果表明铂钯元素均匀地分布在阵列材料上．循环伏安研究发现载有铂钯催化剂的镍纳米管阵列对乙醇氧化的电催化活性明显高于载有铂钯催化剂的镍纳米线阵列．     

强辐射源用铜纳米线阵列靶的结构与性能

 采用多孔阳极氧化铝（AAO）模板脉冲电沉积法制备了强辐射源用铜纳米线阵列靶,并用扫描电子显微镜（SEM）、能谱（EDS）和X射线衍射（XRD）对其进行了结构表征。结果表明：去除AAO模板后铜纳米线平均直径比去除AAO模板前的平均孔径大32%,长度缩短5%。对电沉积2 000 s的样品进行铜纳米线长度分布表征,结果显示:距离模板圆心越远,铜纳米线越长。与超短脉冲激光相互作用实验结果表明:纳米线平均长度在18~50 μm范围内,铜Kα光子产额先随纳米线长度增加而增加,当长度大于33 μm时,铜Kα光子产额开始下降。     

AuPd纳米粒子作为催化剂制备硼纳米线及其场发射性质

利用化学气相沉积法,采用不同组分的金属合金纳米粒子AuPd作为催化剂,在Si(111)基底上成功制备大面积、高密度的硼纳米线薄膜.纳米线的平均长度约为10μm,直径在50—130 nm之间.结构分析表明,纳米线为单晶结构,硼纳米线的直径随着元素Pd在合金催化剂中比例的增加而减少.场发射特性测试结果表明,通过调整催化剂组分可以实现对硼纳米线的尺寸和密度的调控.     

铜钴合金纳米有序阵列的光学特性

用电化学法制备了高度有序的多孔阳极氧化铝模板, 选用CoSO4和CuSO4的混合溶液为电解液,用交流电化学沉积法在多孔阳极氧化铝的柱形微孔内制备铜钴合金纳米线有序阵列.分别用扫描电镜(SEM),X 射线衍射仪(XRD)对多孔氧化铝模板和纳米线阵列的微观形貌和结构进行分析.结果显示,制备的合金纳米线表面光滑、均匀,纳米线中的晶粒在长过程中有(111) 晶面的择优取向.用UV3101分光光度计测试了铜钴合金多孔铝复合结构的透射光谱及偏振光谱表明,合金纳米复合结构在可见及近红外波段具有良好的透射比和消光比;铜钴合金纳米复合结构的确能够改善单一金属的特性,比如在近红外光区,其消光比(30 dB)优于铜纳米复合结构(17 dB).     

掺AlZnO纳米线阵列的光致发光特性研究

采用化学气相沉积方法，以金做催化剂，在Si (100)衬底上制备了掺AlZnO纳米线阵列.扫描电子显微镜(SEM)表征发现ZnO纳米线的直径在30nm左右.X射线衍射(XRD)图谱上只存在ZnO的(002)衍射峰，说明ZnO纳米线沿c轴择优取向.掺AlZnO纳米线阵列的室温光致发光(PL)谱中出现了3个带边激子发射峰：373nm，375nm，389nm.运用激子理论推算出掺AlZnO纳米线的禁带宽度为3.343eV ，束缚激子结合能为0.156eV；纯ZnO纳米线阵列PL谱中3个带边激子发射 关键词： 光致发光 化学气相沉积(CVD) 激子 ZnO纳米线阵列     

高取向As掺杂ZnO纳米线阵列的制备与表征

在不采用任何金属催化剂的条件下,运用化学气相沉积法,在Si(100)衬底上制备出高取向的As掺杂ZnO纳米线阵列.样品的X射线衍射(XRD)谱显示获得了单一取向的衍射峰,表明样品具有较好的结晶质量.场发射扫描电镜(FE-SEM)观察表明,As掺杂ZnO纳米线阵列具有均一的直径和长度,其顶部和根部直径分别为70 nm和1...     

化学气相沉积法制备Zn2GeO4纳米线及其发光性质的研究

利用化学气相沉积法（CVD）,气-液-固（VLS）生长法则在表面溅有金属Au催化剂层的1 cm×1 cm的Si片上制备三元Zn₂GeO₄纳米线。X射线衍射仪（XRD）测试结果表明,锌源与锗源质量比为8：1时可成功制备出Zn₂GeO₄纳米结构;扫描电子显微镜（SEM）测试结果表明,Zn₂GeO₄纳米线直径为100 nm,长度为10~11 μm;光致发光（PL）测试结果表明,Zn₂GeO₄纳米线在432和480 nm处具有两个发光峰,最后对其生长机理进行了分析。     

金刚石锥阵列的无掩膜刻蚀制备及其形貌演变机制

为获得具有优良场发射性能的金刚石锥阵列,利用偏压热灯丝化学气相沉积系统分别在高质量大颗粒金刚石厚膜与纳米金刚石薄膜上进行了无掩膜刻蚀研究,系统比较了高质量大颗粒金刚石厚膜与纳米金刚石薄膜的刻蚀特性,制备了大面积均匀金刚石锥阵列和高长径比(20∶1)金刚石纳米线阵列,探讨了金刚石锥的刻蚀形成机理。     

电化学在ICF靶制备中的新应用

报道了近年来在电解加工技术制备理论密度金属薄膜和电沉积技术制备金属纳米丝阵列材料等领域取得的进展。采用硫酸+甲醇电解液体系获得了表面粗糙度小于30nm的钛膜。采用阳极氧化铝模板电沉积技术制备出长度约10μm、直径约300nm的金纳米丝阵列。主要讨论了电解液配方及电解加工参数的选择,金属纳米丝直径与长度的控制等问题。     

模板法交流沉积金纳米线的影响因素

使用交流电沉积在多孔氧化铝模板中制备金纳米线,对交流电沉积时阻挡层厚度、交流电压、交流频率等因素进行了系统的研究和探讨。使用交流电沉积制备出了直径30 nm、长度2.1 m的形貌完好、长度均一的金纳米阵列。结果表明模板的阻挡层厚度能够显著影响金属的沉积电位,是保证沉积顺利进行的重要因素。通过记录、分析不同条件下交流沉积过程中时间-电流曲线来对交流沉积过程进行深入研究并提出相应机理。发现同频率下平台电流值不变,纳米线的长度与交流电压大小成正比,而同电压下沉积的平台电流与交流电频率成正比,这些都与阻挡层的半导体特性有关。     

Electrostatic assembly of CTAB-capped silver nanoparticles along predefined λ-DNA template

Cetyltrimethylammonium bromide (CTAB)-capped positively-charged silver nanoparticles synthesized in water-ethanol system was electrostatic assembled on predefined aligned λ-DNA template. Silver nanowire can be obtained by changing the reaction time and the particles concentration. In our work, the length of the silver nanowire obtained is about 10 μm, and the dimension of the wires is about 20 nm. AFM data reveal that the assembly of CTAB-capped silver nanoparticles on DNA is ordered, but there is space between two particles absorbed on the DNA template. X-ray photoelectron spectroscopy (XPS) was applied to characterize the linear silver clusters, which provides an additional proof that the silver particles were assembled onto DNA template with fine order.     

Anisotropic optical response of GaN and AlN nanowires

We present a theoretical study of the electronic structure and optical properties of free-standing GaN and AlN nanowires. We have implemented the empirical tight-binding method, with an orbital basis sp(3), that includes the spin-orbit interaction. The passivation of the dangling bonds at the free surfaces is also studied, together with the effects on the electronic structure of the nanowire. For both GaN and AlN nanowires, we have found a remarkable anisotropy of the optical absorption when the light-polarization changes, showing in the case of GaN a dependence on the nanowire size.     

Introducing voids around the interlayer of AlN by high temperature annealing

Introducing voids into AlN layer at a certain height using a simple method is meaningful but challenging. In this work, the AlN/sapphire template with AlN interlayer structure was designed and grown by metal-organic chemical vapor deposition. Then, the AlN template was annealed at 1700 ℃ for an hour to introduce the voids. It was found that voids were formed in the AlN layer after high-temperature annealing and they were mainly distributed around the AlN interlayer. Meanwhile, the dislocation density of the AlN template decreased from 5.26×10⁹ cm^-2 to 5.10×10⁸ cm^-2. This work provides a possible method to introduce voids into AlN layer at a designated height, which will benefit the design of AlN-based devices.     

Formation and growth mechanism of ripple-like AlN nanowires

Single-crystal ripple-like AlN nanowire with tuned diameter was fabricated through direct reaction aluminum with nitrogen by arc discharge method. The nanowires grow along the [0001] direction and have a radial expansion along the [10[`1]0][10\bar{1}0] direction. The periodic variation of the radial expansion toward [10[`1]0][10\bar{1}0] direction produces the ripple-like AlN nanowires. The growth mechanism of the AlN nanowires is discussed by considering the Al adlayer diffusion on the polar (0001) surface.     

Magnetic coupling properties of Mn-doped AlN nanowires: First-principles calculations

Based on first-principles within the framework of the density functional theory, we have studied the magnetic coupling properties of Mn-doped AlN nanowires. By analyzing the results of different Mn-doped AlN nanowires, we found that for the passivated nanowire, ferromagnetic state is more stable, while for the unpassivated nanowire, the favorable state transits into anti-ferromagnetic state, which can be well explained by the band coupling model. The results indicate that the degree of surface passivation of dangling bonds is an important factor in the magnetic properties of doped nanowires.     

Analysis of the local atomic structure of aluminum nitride nanoparticles

The structure of synthesized AlN nanoparticles was studied based on the theoretical analysis of X-ray absorption spectra near the K-absorption edge of aluminum. The method of full multiple scattering and finite difference method were used for theoretical calculations. The set of phases being present in nanoparticles and concentrations of different phases are determined. It turned out that besides cubic and hexagonal AlN phases the pure Al metal phase is present in synthesized objects.     

低温CVD法在玻璃衬底上制备ZnO纳米线阵列

采用化学气相沉积(CVD)法在镀Cr(20nm)的玻璃衬底上,低温制备了ZnO纳米线阵列。利用扫描电子显微镜(SEM)和X射线衍射(XRD)对样品的表面形貌和微结构进行了分析表征。结果表明:源分解温度1350℃,衬底温度450～500℃,氩气流量为35sccm时,ZnO纳米线在玻璃衬底上呈现有序生长;XRD谱图中只观测到ZnO(002)衍射峰。表明制备的纳米线阵列具有高度c轴择优取向生长特性和较高的结晶质量。     

Domain wall pinning controlled by the magnetic field of four nanoparticles in a ferromagnetic nanowire

This paper presents the results of theoretical and experimental investigations of the domain wall pinning in a planar ferromagnetic system consisting of a nanowire and four rectangular uniformly magnetized nanoparticles located at an angle to the nanowire axis. Based on the calculations of the interaction energy of the domain wall with stray fields of nanoparticles and the micromagnetic simulation, it has been demonstrated that, in this system, there are different variants of the domain wall pinning, which are determined by the relative orientation of the magnetic moments of nanoparticles and the magnetization of the nanowire. The possibility of the creation of magnetic logic cells based on the structures under consideration has been discussed.     

AlN在AlN/VN纳米多层膜中的相转变及其对薄膜力学性能的影响

采用反应磁控溅射制备了AlN/VN纳米多层膜.研究了多层膜调制周期对AlN生长结构的影响以 及纳米多层膜的力学性能.结果表明：小周期多层膜中的AlN以亚稳的立方相(c-AlN)存在并 与VN形成共格外延生长的超晶格.薄膜产生硬度和弹性模量升高的超硬效应.大调制周期下， AlN从立方结构转变为稳定的六方相（h-AlN），并使多层膜形成纳米晶的“砖墙”型结构. 讨论认为VN的模板作用有利于c-AlN的生长，但不能显著提高其临界厚度. 关键词： 薄膜的力学性能 外延生长 亚稳相     

Domain wall pinning in a ferromagnetic nanowire by stray fields of nanoparticles

Domain wall pinning in a planar ferromagnetic system consisting of a nanowire and two uniformly magnetized nanoparticles parallel to it is investigated. Micromagnetic simulations and calculations of the energy of interaction between domain wall and stray fields of nanoparticles show that four variants of domain wall pining are observed in such a system and are determined by the relative orientation of magnetic moments of nanoparticles and the magnetization of the nanowire.