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1.
Yin S Chen Y Su Y Jia C Zhou Q Li S Xin M Kong W Zhang X Lü Y 《Journal of nanoscience and nanotechnology》2008,8(2):993-996
Well-aligned ZnO nanorods and nanopins are synthesized on a silicon substrate using a one-step simple thermal evaporation of a mixture of zinc and zinc acetate powder under controlled conditions. A self-assembled ZnO buffer layer was first obtained on the Si substrate. The structure and morphology of the as-synthesized ZnO nanorod and nanopin arrays are characterized using X-ray diffraction, and scanning and transmission electron microscopies, energy-dispersive X-ray spectroscopy, and photoluminescence spectroscopy. The influence of the background atmosphere on the two ZnO nanostructures has been studied. Two different growth mechanisms are mentioned to interpret the formation of ZnO nanorod and nanopin arrays in our work. The room-temperature PL features the ZnO nanorods exhibit only sharp and strong ultraviolet (UV) emission emissions, which confirms the better crystalline and optical quality than the ZnO nanopins. 相似文献
2.
《Materials Letters》2007,61(4-5):1170-1173
Radial and quasi-aligned ZnO nanorod arrays were prepared on Si(111) substrates by a simple vapor phase method using Zn and zinc acetate dihydrate (ZA) as the source materials. X-ray diffraction, field emission scanning electron microscopy, Raman scattering and photoluminescence were used to characterize the structural and optical properties of the obtained nanostructures. The growth mechanisms of the two kinds of ZnO nanostructures were discussed based on the growth conditions. The different decomposing rate of the ZA plays an important role in the initial nucleation of ZnO nanorods. 相似文献
3.
Growth and comparison of different morphologic ZnO nanorod arrays by a simple aqueous solution route
A simple aqueous solution route has been successfully employed to prepare large-scale arrays of ZnO nanorods on the zinc foil without the assistance of any template, oxidant or coating of metal oxide layers. It is found that the growth of ZnO nanorod arrays with different densities, diameters and morphologies is dependent on the ammonia concentration and zinc precursor. The different morphologies of the ZnO nanostructures attained with or without adding Zn2+-contained salt in the alkaline solution are compared in the paper. The possible growth mechanism concerning the growth of the different ZnO nanocrystal morphologies is also discussed. 相似文献
4.
A controlled synthesis of flower-?and rod-like ZnO nanostructures in a hydrothermal phase has been realized in the absence of an additional template. The well-defined morphologies are obtained by simply tuning the ratio of sodium hydroxide to zinc acetate in a narrow range. The products are characterized by powder x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The growth mechanism is suggested to be that the supersaturation of the precursor Zn(OH)(4)(2-) results in various nucleation habits, which induce the ZnO nanostructures with different morphologies. 相似文献
5.
Li X Zhang F Ma C Deng Y Wang Z Elingarami S He N 《Journal of nanoscience and nanotechnology》2012,12(3):2028-2036
ZnO microstructures with various morphologies have been controllably synthesized by hydrothermal route using different precipitant and zinc source in liquid solution. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the ZnO2, Zn(OH)2 and ZnO structures to understand the role of precipitant and precursors in the growth of various morphologies. The nucleation and growth process can regulate by changing the precipitant. When H2O2 was used as precipitant, ZnO particles with a rather uniform particle size of -500 nm and a rather rough surface was obtained. While, ZnO synthesized in this polyvinyl pyrrolidone (PVP) solution has the same granular morphology with particle size of 300-1000 nm. In contrast, ZnO sunflower and polyhedron aggregates composed of several smaller polyhedron were formed, when ammonium hydroxide and NH4HCO3 was applied, respectively. Meanwhile, precursors play an important role in the determination of the morphology of ZnO. Sunflower and dumbbell like ZnO composed of nanosheets were obtained, when different centrifugal component of Zn(OH)2 suspension was applied as zinc source. In contrast, sunflower and dumbbell like ZnO composed of nanorods and ZnO rods were obtained, when different centrifugal components of ZnO2 suspension were used as zinc sources. The growth mechanism of ZnO nanostructures fabricated by the hydrothermal process using different zinc sources was tentatively investigated. 相似文献
6.
Zn/ZnO metal/semiconductor nanostructures were successfully synthesised by a facile zinc-rich chemistry liquid-phase approach with zinc microspheres as sacrificial templates at ambient temperature. A series of globular Zn/ZnO core/shell structures and hollow microsphere architectures self-assembled by Zn/ZnO nanorod heterojunction arrays were obtained by controlling the amount of zinc particles. The structure, morphology, composition and optical properties of the products have been characterised by X-ray diffraction, scanning electron microscopy, Raman spectroscopy and photoluminescent spectroscopy. A possible growth mechanism of the Zn/ZnO nanostructures has been proposed based on the structural analysis. The growth mechanism of Zn/ZnO hollow microspheres is ascribed to Kirkendall effect. A new strong blue emission at 440 nm and a green emission around 500 nm with an enhancement over one order of magnitude compared with the pure ZnO sample have been observed. These emission bands are attributed to two kinds of mechanisms that have been discussed in detail. 相似文献
7.
Umar A Kim SH Kim JH Park YK Hahn YB 《Journal of nanoscience and nanotechnology》2007,7(12):4421-4427
Flower-shaped ZnO nanostructures, containing the triangular-shaped petals (sharpened tips and wider bases) have been achieved by simple thermal evaporation of high purity metallic zinc powder in the presence of oxygen at 440 degrees C on steel alloy substrate without the use of metal catalyst or additives. Detailed structural studies confirm that the obtained flower-shaped nanostructures are single crystalline and possesses a wurtzite hexagonal structure, grown along the c-axis in the [0001] direction. Raman and room temperature photoluminescence analysis substantiate a wurtzite hexagonal phase with a good crystal quality and a strong UV emission at 378 nm, respectively, indicating few or no structural defects. Additionally, a detailed possible growth mechanism has also been discussed. 相似文献
8.
Xiaolan Chen Ya-Bo Zhu Zheng Xing Guoxia Tang Heliang Fan 《Journal of Materials Science: Materials in Electronics》2016,27(2):1151-1157
Four different mediums have been developed for the synthesis of PbSe nanostructures, with different size and morphology. The particles were obtained in solid state medium with size of only 60 nm on average which are much smaller than those gained in liquid and molten state mediums. The growth mechanisms of these PbSe nanostructures were discussed. Results show that the state of medium have a direct impact on the size of PbSe nanostructures and the alkalinity of environment plays a key part in the formation of PbSe nanocubes. On the other hand, the electrochemical property of two typical nanostructures was studied. In the CV curves, there are four reaction peaks corresponding to oxidation of the PbSe and Pb(OH)2, and the reduction of PbO2 and Pb(OH)2. Otherwise, nanorods with size of only 60 nm have greater structural stability than nanocubes. 相似文献
9.
Zinc oxide (ZnO) multipod nanoneedles over a large area have been synthesized on silicon substrate by thermally oxidizing zinc foil at 650 °C. These nanoneedles have sharp tails with diameter down to less than 100 nm, with length of 10 μm, growing from the surface of the silicon substrate and legs connected at a common base. X-ray diffraction (XRD) confirmed the sample as pure ZnO nanostructures with growth direction of [002]. The cathode luminescence behaviors at different regions of an individual nanoneedle of these multipod ZnO nanostructures were characterized. It is shown the whole nanostructures are luminescent, while the tips have relative higher visible emission than the bottom. The cathode luminescence mechanisms were also discussed. 相似文献
10.
11.
Jinxia Duan Qiu Xiong Hao Wang Jun Zhang Jinghua Hu 《Journal of Materials Science: Materials in Electronics》2017,28(1):60-66
Controlled ZnO nanostructures were synthesized via spin-coating and in situ thermal decomposition processing using ZnO paster with/without zinc acetate as precursor. The perovskite CH3NH3PbI3 solar cells (PSCs) based on these ZnO nanostructures were fabricated and their photovoltaic performances have also been investigated. Effects of zinc acetate concentration on morphologies of ZnO nanostructures and the photovoltaic properties of corresponding PSCs have been discussed. Interestingly, the morphologies of ZnO nanostructures were varied from separate nanoparticles to interconnect net-like nanostructures and the space of ZnO nanoparticles became large when the concentration of zinc acetate was increased from 0 to 0.13 M. The space and the connection degree of ZnO nanostructure obtained from 0.05 M zinc acetate are the best choice for perovskite infiltration and charge transport, which leads to corresponding cells have highest power conversion efficiencies (PCE) of 9.30 %. Post-treatment of ZnO nanostructures improved further Voc and FF, leading to PCE to 13.1 %. 相似文献
12.
Q.R. Hu 《Materials Letters》2010,64(16):1822-528
ZnO nanostructures were fabricated in the ethanol solution of different alkali by a surfactant-free solvothermal method. ZnO nanoparticles, nanowires and nanorods were obtained depending on the experimental conditions. The corresponding growth mechanism follows a typical self-assembly growth process. The effects of various alkalis on the structures and morphologies of ZnO nanostructures were investigated. Moreover, the photoluminescence (PL) properties of the ZnO nanostructures were studied and exhibited some new features. It is found that the surface defects should be responsible for the green emission observed in the as-prepared ZnO nanostructures. The higher the specific surface area of ZnO nanostructures, the stronger the green emission and the weaker the ultraviolet (UV) emission are. 相似文献
13.
One-dimensional (1D) zinc oxide (ZnO) nanostructures have been extensively and intensively studied for several decades not only for their extraordinary chemical and physical properties, but also for their current and future different electronic and optoelectronic device applications. This review provides a brief overview of the progress of different synthesis methods and applications of 1D-ZnO nanostructures. Morphology of ZnO nanostructures grown by various methods and progress in the optical properties are briefly described. Using low-temperature photoluminescence (LTPL) study, detailed informations about the defect states and impurity of such nanostructures are reported. Improvement of field emission properties by modifying the edge of 1D-ZnO nanostructures is briefly discussed. Applications such as different sensors, field effect transistor, light-emitting diodes (LEDs), and photodetector are briefly reviewed. ZnO has large exciton binding energy (60 meV) and wide band gap (3.37 eV), which could lead to lasing action based on exciton recombination. As semiconductor devices are being aggressively scaled down, ZnO 1D nanostructures based resistive switching (RS) memory (resistance random access memory) is very attractive for nonvolatile memory applications. Switching properties and mechanisms of Ga-doped and undoped ZnO nanorods/NWs are briefly discussed. The present paper reviews the recent activities of the growth and applications of various 1D-ZnO nanostructures for sensor, LED, photodetector, laser, and RS memory devices. 相似文献
14.
Two types of zinc oxide (ZnO)-tubular nanostructures have been fabricated by stepped gas-phase reaction of a mixture of Zn–ZnO powders. Tubular structures of Type I vaporized from the top of ZnO nanorods with several hundreds nanometer in diameter. Tubular structures of Type II-coalesced ZnO nanowires with 2–4 μm in diameter. The formation of these two types of ZnO-tubular nanostructures is governed by different reaction conditions such as temperature, atmosphere, pressure, etc., and their growth mechanisms are discussed in detail. 相似文献
15.
Sanjaya Brahma Kalya Jagannatha Rao Srinivasarao Shivashankar 《Bulletin of Materials Science》2010,33(2):89-95
Large quantities of single-crystalline ZnO nanorods and nanotubes have been prepared by the microwave irradiation of a metalorganic
complex of zinc, in the presence of a surfactant. The method is simple, fast, and inexpensive (as it uses a domestic microwave
oven), and yields pure nanostructures of the hexagonal würtzite phase of ZnO in min, and requires no conventional templating.
The ZnO nanotubes formed have a hollow core with inner diameter varying from 140–160 nm and a wall of thickness, 40–50 nm.
The length of nanorods and nanotubes varies in the narrow range of 500–600 nm. These nanostructures have been characterized
by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area
electron diffraction (SAED). The ZnO nanorods and nanotubes are found by SAED to be single-crystalline. The growth process
of ZnO nanorods and nanotubes has been investigated by varying the surfactant concentration and microwave irradiation time.
Based on the various results obtained, a tentative and plausible mechanism for the formation of ZnO nanostructures is proposed. 相似文献
16.
Complex and oriented ZnO nanostructures 总被引:7,自引:0,他引:7
Tian ZR Voigt JA Liu J McKenzie B McDermott MJ Rodriguez MA Konishi H Xu H 《Nature materials》2003,2(12):821-826
Extended and oriented nanostructures are desirable for many applications, but direct fabrication of complex nanostructures with controlled crystalline morphology, orientation and surface architectures remains a significant challenge. Here we report a low-temperature, environmentally benign, solution-based approach for the preparation of complex and oriented ZnO nanostructures, and the systematic modification of their crystal morphology. Using controlled seeded growth and citrate anions that selectively adsorb on ZnO basal planes as the structure-directing agent, we prepared large arrays of oriented ZnO nanorods with controlled aspect ratios, complex film morphologies made of oriented nanocolumns and nanoplates (remarkably similar to biomineral structures in red abalone shells) and complex bilayers showing in situ column-to-rod morphological transitions. The advantages of some of these ZnO structures for photocatalytic decompositions of volatile organic compounds were demonstrated. The novel ZnO nanostructures are expected to have great potential for sensing, catalysis, optical emission, piezoelectric transduction, and actuations. 相似文献
17.
《Materials Science & Technology》2013,29(10):1248-1252
AbstractIntriguing ZnO three-dimensional (3D) dendritic nanorods on silicon substrates have been successfully synthesised by thermal evaporation of pure zinc powder at a relative low temperature of 478°C without any metal catalyst. ZnO dendritic nanostructure exhibits unique shape and it is composed of stems and nanorod branches. It is found that the nanorods are single crystalline wurtzite structures, and each nanorod grows along the [0001] direction. At different growth temperatures, the shapes of ZnO nanostructures can be altered. System analysis reveals that the formation and morphology of ZnO dendritic nanostructures are sensitive to the growth temperature. Finally, room temperature photoluminescence spectrum is also investigated, revealing that the ZnO dendritic nanostructure could find application in UV optoelectronic devices; the nanostructure implies some potential applications for nanoscale functional devices. 相似文献
18.
ZnO纳米材料的p型掺杂研究进展 总被引:1,自引:0,他引:1
随着近年来各种形貌ZnO纳米材料的生长及ZnO纳米器件的研究,ZnO纳米材料的p型掺杂逐渐成为研究的重点之一.主要介绍了ZnO纳米材料的p型掺杂及其器件研究进展,简要讨论了当前掺杂研究的局限,展望了今后的发展方向. 相似文献
19.
Synthesis of various ZnO nanostructures for different zinc to ammonia concentration ratios by a single-step aqueous chemical method at relatively low temperature is reported here. These nanostructures show preferential growth along (002) direction as observed in XRD. Morphological characterization by SEM, TEM, HRTEM, and SAED patterns reveal the formation of nanostructures of different shape, size, aspect ratio, and the crystal lattice orientations, which are mainly influenced by zinc to ammonia concentration. These materials when used as photo anodes in dye sensitized solar cells, the sample with the mixture of pyramidal, short nanorods, and spherical nanoparticle exhibits maximum conversion efficiency of 0.123 % due to better dye loading and direct conduction pathway for electron transport. 相似文献
20.
Jingbiao Cui 《Journal of Materials Science: Materials in Electronics》2008,19(8-9):908-914
Zinc oxide nanostructures were synthesized in an aqueous solution of hexamine and zinc nitrate by an electrochemical process. The effects of growth conditions, including electrical potential, growth temperature and template size, on morphology and composition of the nanostructures were systematically investigated. A negative potential enhanced the growth of single crystalline ZnO nanowire arrays while a positive potential caused nano-disks of ZnO and ZnO2 composites to grow on the substrate. The applied negative potential also helped room temperature growth of ZnO nanowires with a reduced growth rate. Similar growth behavior was observed on a bare substrate and that with pre-defined polymer template. 相似文献