Mg掺杂GaN纳米线的结构及其特性

利用类似Delta掺杂技术在硅衬底上沉积Mg:Ga2O3薄膜, 然后在850 ℃下对薄膜进行氨化, 反应后制备出大量Mg掺杂GaN纳米线. 采用扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱和高分辨透射电子显微镜(HRTEM)对样品进行分析.结果表明, Mg掺杂GaN纳米线具有六方纤锌矿单晶结构, 纳米线的直径在30-50 nm范围内, 长度为几十微米.     

利用Pd催化合成单晶GaN纳米线的光学特性(英文)

基于金属元素钯具有的催化特性,采用射频磁控溅射方法,在Si(111)衬底上沉积Pd:Ga2O3薄膜,然后在950℃下对薄膜进行氨化,制备出大量GaN纳米线.采用扫描电子显微镜(SEM)、X射线衍射(XRD)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)等技术手段对样品的结构、形貌和成分进行分析.结果表明,制备的样品为具有六方纤锌矿结构的单晶GaN纳米线,直径在20-60nm范围内,长度为几十微米,表面光滑无杂质,结晶质量较高.用光致发光光谱对样品的发光特性进行测试,分别在361.1、388.6和426.3nm处出现三个发光峰,且与GaN体材料相比近带边紫外发光峰发生了较弱的蓝移.对GaN纳米线的生长机制也进行了简单的讨论.     

GaN纳米棒的催化合成及其发光特性

使用稀土元素Tb作催化剂, 通过氨化溅射在Si(111)衬底上的Ga2O3/Tb薄膜, 成功制备出GaN纳米棒. X射线衍射测试显示, GaN纳米棒具有六方结构. 利用扫描电子显微镜和高分辨透射电子显微镜观察分析得出, 纳米棒为单晶GaN, 纳米棒的直径为50-150 nm, 长度约10 μm. 光致发光谱在368.6 nm处有一强的紫外发光峰, 说明纳米棒具有良好的发光特性. 讨论了GaN纳米棒的生长机制.     

Ag作催化剂制备的GaN的形貌及其性能

用化学气相沉积法(CVD)在Si(100)衬底上以Ag纳米颗粒为催化剂制备了微纳米结构的GaN,原料是熔融态的金属Ga和气态的NH3。采用X射线衍射仪(XRD)、透射电镜(TEM)、X-ray能谱仪(EDS)、场发射扫描电子显微镜(SEM)、光致发光能谱(PL)和霍尔效应测试对样品进行了结构、成分、形貌和发光、电学性能分析。结果表明:生成的自组装GaN为六方纤锌矿的类似小梯子的微纳米单晶结构,且在不同的温度下,GaN的发光性能和电学性能也有所不同,相对于强的紫外发光峰,其它杂质发光峰很微弱,且均呈p型导电。对本实验所得到的GaN微纳米结构的可能形成机理进行了探讨。     

Synthesis and synchrotron light-induced luminescence of ZnO nanostructures: nanowires, nanoneedles, nanoflowers, and tubular whiskers

ZnO nanostructures, including single-crystal nanowires, nanoneedles, nanoflowers, and tubular whiskers, have been fabricated at a modestly low temperature of 550 degrees C via the oxidation of metallic Zn powder without a metal catalyst. Specific ZnO nanostructures can be obtained at a specific temperature zone in the furnace depending on the temperature and the pressure of oxygen. Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) studies show that ZnO nanostructures thus prepared are single crystals with a wurtzite structure. X-ray excited optical luminescence (XEOL) from the ZnO nanostructures show noticeable morphology-dependent luminescence. Specifically, ZnO nanowires of around 15 nm in diameter emit the strongest green light. The morphology of these nanostructures, their XEOL, and the implication of the results will be discussed.     

海藻酸锌纤维热降解法制备氧化锌纳米结构

采用天然高分子海藻酸钠为原料, 以氯化锌水溶液为凝固浴, 通过湿法纺丝技术成功制备了海藻酸锌(Alg-Zn)纤维.通过在空气中不同温度下对所得海藻酸锌纤维进行热处理, 得到了多种ZnO纳米结构. 利用热失重分析(TG)、X射线衍射(XRD)、电子能量损失谱(EELS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)等手段对产物的组成、形貌和微观结构进行了详细表征. 结果表明, 焙烧温度和时间对所得ZnO纳米结构的尺寸和形貌具有重要影响; 800 ℃下热处理24 h以上可以得到直径约为120 nm的ZnO纳米棒. 通过仔细考察不同热处理时间得到的ZnO纳米结构, 提出了在焙烧条件下ZnO纳米棒的生长机理.     

Effect of titania structure on the properties of its supported copper oxide catalysts

A facile and rapid microwave irradiation method was explored for the synthesis of bismuth phosphate (BiPO(4)) nanostructures with various morphologies and phases in different solvents. The BiPO(4) products were characterized by powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS). The effect of the solvents on the formation of the BiPO(4) nanostructures was discussed on the basis of experimental results. The different BiPO(4) nanostructures exhibited different optical properties, BET surface areas and photocatalytic activities on the degradation of methyl orange (MO) under UV and visible light irradiation. The experimental results suggested that the photocatalytic activity was closely relative with the crystalline phase and band gap of BiPO(4). Hexagonal BiPO(4) nanoparticles with narrow band gap showed the highest photocatalytic performance.     

Single‐Crystalline ZnO Nanowire Bundles: Synthesis,Mechanism and Their Application in Dielectric Composites

Single‐crystalline ZnO nanowire bundles have been synthesized in large‐scale by an improved microemulsion method in the presence of excessive hydrate hydrazine and dodecyl benzene sulfonic acid sodium salt (DBS) in xylene. The product is characterized using X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high‐resolution transmission electron microscopy (HRTEM). The result shows that the bundle is composed by many oriented single‐crystalline ZnO nanowires with a length of about 1 μm and a diameter of about 20–30 nm. The influence of DBS, hydrazine and the reaction time on the morphology of final product and the formation mechanism of such nanostructures were discussed; the application in the dielectric composites is also studied.     

N2流量对GaN的形貌及光学和电学性能的影响

采用化学气相沉积法(CVD)在Si(100)衬底上以Ni为催化剂, 金属Ga和NH₃为原料合成了GaN微纳米结构, 并研究了N₂流量对产物GaN的形貌及光学和电学性能的影响。利用场发射扫描电子显微镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、X-ray能谱仪(EDS)、光致发光谱(PL)和霍尔效应测试仪(HMS-3000)等测试手段对样品的形貌、结构、成分、光学和电学性能进行了分析。结果表明, 随着N₂流量的增加, 产物GaN的形貌发生了由微米棒到蠕虫状线再到光滑纳米线的转变;生成的GaN均为六方纤锌矿结构;样品均表现出383 nm的近带边紫外发射峰和470 nm左右的蓝光发射峰;所有样品均为n型;并对产物GaN的形貌转变机理进行了分析。     

Shape-controlled solvothermal synthesis of bismuth subcarbonate nanomaterials

Much effort has been devoted to the synthesis of novel nanostructured materials because of their unique properties and potential applications. Bismuth subcarbonate ((BiO)₂CO₃) is one of commonly used antibacterial agents against Helicobacter pylori (H. pylori). Different (BiO)₂CO₃ nanostructures such as cube-like nanoparticles, nanobars and nanoplates, were fabricated from bismuth nitrate via a simple solvothermal method. The nanostructures were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It was found that the solvents and precursors have an influence on the morphologies of (BiO)₂CO₃ nanostructures. The possible formation mechanism of different (BiO)₂CO₃ nanostructures fabricated under different conditions was also discussed.     

不同形貌ZnO纳米结构的电子显微分析

控制实验合成条件,利用溶胶-凝胶法和化学溶液生长法制备出不同形貌的ZnO纳米结构。采用X射线衍射仪(XRD)、扫描电子显微镜( SEM) 以及透射电子显微镜(TEM)等多种测试手段对ZnO纳米结构的微观形态及晶相进行了分析。结果表明:3种ZnO纳米结构形貌虽不同,但均具有Z nO六方纤锌矿晶相结构。ZnO纳米棒和花状ZnO纳米结构为单晶,生长方向均沿(0001)方向。ZnO纳米球则为多晶。     

聚合物控制CuO纳米盘的液相生长

表面活性剂聚丙烯酰胺（PAM）的控制下,在温和的低温水溶液中,高产率的CuO纳米盘被合成。粉未衍射（XRD）,扫描电镜（SEM）,高分辨透射电子显微（HRTEM）对产物的形貌结构进行表征。研究了不同反应条件如温度、PAM浓度等对产物形貌与尺寸的影响。结果表明,CuO纳米盘为单晶结构,沿着（002）和（110）面生长。PAM对纳米盘的形成起到关键作用。典型的聚合物-晶体作用生长机理用来解释CuO纳米盘的形成。聚合物诱引晶体生长与调控纳米晶自组装将提供了一条有效的路径来合成具有复杂形貌与特殊结构的无机和无机-有机杂化材料。     

GaN and GaxIn1−xN Nanoparticles with Tunable Indium Content: Synthesis and Characterization

Semiconducting GaN and Ga_xIn_1?xN nanoparticles (4–10 nm in diameter, depending on the metal ratio) with tunable indium content are prepared through a chemical synthesis (the urea‐glass route). The bandgap of the ternary system depends on its composition, and therefore, the color of the final material can be turned from bright yellow (the color of pure GaN) to blue (the color of pure InN). Transmission electron microscopy (TEM and HRTEM) and scanning electron microscopy (SEM) images confirm the nanoparticle character and homogeneity of the as‐prepared samples. X‐ray diffraction (XRD), electron diffraction (EDX), elemental mapping, and UV/Vis, IR, and Raman spectroscopy investigations are used to confirm the incorporation of indium into the crystal structure of GaN. These nanoparticles, possessing adjusted optical properties, are expected to have potential applications in the fabrication of novel optoelectronic devices.     

钨酸锌纳米结构的水热合成及其光催化性能研究

使用柠檬酸钠辅助的水热法合成了具有不同形貌的ZnWO4(如片状、花状)纳米颗粒,并采用X-射线粉末衍射(XRD)、场发射扫描电子显微镜(FESEM)、高分辨透射电子显微镜(HRTEM)等方法对样品的结构和组成进行表征。研究了溶剂组分和溶液pH值对产物形貌的影响。通过对反应产物形貌随时间变化的观察,提出了片状和花状ZnWO4纳米颗粒可能的生长机理。以罗丹明B(RhB)为催化降解对象,对样品在水溶液中的光催化性质进行了研究。结果表明,ZnWO4纳米颗粒的比表面积和孔径尺寸等结构特性对其光催化活性具有明显影响。     

pH sensitive swelling and releasing behavior of nano-gels based on polyaspartamide graft copolymers

Dendritic and porous Ag-Pd alloy nanostructures were successfully fabricated on the surface of silicon substrate using the co-reduction method and galvanic replacement reaction, respectively. The molar compositions of Ag and Pd in the alloy could be modulated by controlling the molar ratios of metal precursors and reaction time. The Ag-Pd alloy nanostructures were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD). The morphology and phase of Au-Pd alloy nanostructures were discussed as a function of molar ratios of metal precursors and reaction time. In addition, the morphology and composition-dependent surface-enhanced Raman scattering (SERS) of the as-synthesized Ag-Pd alloy nanostructures were investigated. The SERS enhancement factor was estimated and SERS mapping was performed to prove the homogeneity of these substrates. The results indicate that as-synthesized dendritic and porous Ag-Pd alloy nanostructures are good candidates for SERS spectroscopy.     

一种在固体基底上制备高度取向氧化锌纳米棒的新方法

采用廉价、低温的方法，在修饰过ZnO纳米粒子膜的ITO基底上成功制备出具有 高长径比、高度取向的ZnO纳米棒阵列，用扫描电子显微镜(SEM)，X射线衍射(XRD) ，高分辨透射电子显微镜(HRTEM)以及拉曼光谱对制备出的ZnO纳米棒的结构和形貌 进行了表征，测试结果表明，ZnO纳米棒是单晶，属于六方晶系，与基底直，上仍 沿(001)晶面择优生长的特征，并且ZnO纳米棒基本上无氧空位的存在，统计结果显 示，水热反应2h后90%以上的ZnO纳米棒直径为120～190nm，长度为4μm     

气-固相还原硫酸盐制备系列硫化物纳米晶

<正>过渡金属硫化物纳米晶因其特异的结构具有量子尺寸效应、小尺寸效应、表面效应等效应,显示出不同于体相材料的光电磁性质,因而成为近年来纳米科学研究的热点[1-3]。几十年来,硫化亚铁(FeS)     

WO3/TiO2 复合纤维的制备及储能光催化性能

以钛酸正丁酯为前驱体, 采用静电纺丝技术制得了纯锐钛矿TiO2纤维, 并以其为基质, 通过水热法制备了具有异质结构的WO3/TiO2复合纤维. 利用X射线衍射仪(XRD)、 扫描电子显微镜(SEM)、 能量色散光谱仪(EDS)、 透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)等对样品的结构和形貌进行了表征. 以罗丹明B的脱色降解为模型反应, 考察了样品的光催化性能和储能光催化性能. 结果表明, 花状WO3微球包裹在TiO2纤维上, 得到了具有异质结构的WO3/TiO2复合纤维光催化剂. WO3与TiO2复合有利于光生载流子的输运和分离, 增强了体系的量子效率, 提高了光催化活性. WO3/TiO2 复合纤维经光照处理后, 在黑暗条件下显示出储能光催化特性.     

Self-catalyst growth of single-crystalline CaB6 nanostructures

Large-scale calcium hexaboride (CaB₆) nanostructures have been successfully fabricated with self-catalyst method using calcium (Ca) powders and boron trichloride (BCl₃) gas mixed with hydrogen and argon. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected-area electron diffraction (SAED) were used to characterize the compositions, morphologies, and structures of the samples. Our results show that the nanowires are highly single crystals elongated preferentially in the [1 1 0] direction. The growth mechanism based on the self-catalyst process is simply discussed.     

Synthesis and characterization of indium-doped ZnO nanowires with periodical single-twin structures

In-doped ZnO (IZO) nanowires have been synthesized by a thermal evaporation method. The morphology and microstructure of the IZO nanowires have been extensively investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The products in general contain several kinds of nanowires. In this work, a remarkable type of IZO zigzag nanowire with a periodical twinning structure has been investigated by transmission electron microscopy (TEM). HRTEM observation reveals that this type of IZO nanowire has an uncommonly observed zinc blend crystal structure. These nanowires, with a diameter about 100 nm, grow along the [111] direction with a well-defined twinning relationship and a well-coherent lattice across the boundary. In addition, an IZO nanodendrite structure was also observed in our work. A growth model based on the vapor-liquid-solid mechanism is proposed for interpreting the growth of zigzag nanowires in our work. Due to the heavy doping of In, the emission peak in photoluminescence spectra has red-shifted as well as broadened seriously.