Synthesis and Optical Properties of Hollow Spheres Self-Assembled by ZnO Nanocrystals

2011 ◽  
Vol 236-238 ◽  
pp. 2019-2023
Author(s):  
Xiao Min Meng ◽  
Ai Min He
Keyword(s):  
Electron Microscopy ◽  
Hollow Spheres ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Benzene Sulfonic Acid ◽  
Zno Nanocrystals ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Dodecyl Benzene Sulfonic Acid ◽  
Self Assembled

Nano-sized hollow spheres self-assembled by ZnO nanocrystals have been prepared by microemulsion method with dodecyl benzene sulfonic acid sodium salt (DBS) as the modifying and protecting agent. The product was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high High-resolution electron microscopy (HRTEM) energy dispersive spectroscopy (EDS) and photoluminescence (PL) spectra. The results showed that the hollow sphere was composed of ZnO nanocrystals. And the PL spectrum showed a different emission at 438 nm. After heated the product, PL emission peak changed. A possible formation mechanism was also proposed.

Transmission electron microscopy observation in a liquid-phase-sintered SiC with oxynitride glass

2001 ◽  
Vol 16 (8) ◽  
pp. 2189-2191 ◽  
Author(s):  
Guo-Dong Zhan ◽  
Mamoru Mitomo ◽  
Young-Wook Kim ◽  
Rong-Jun Xie ◽  
Amiya K Mukherjee
Keyword(s):  
Electron Microscopy ◽  
Liquid Phase ◽  
High Resolution Electron Microscopy ◽  
Nitrogen Atmosphere ◽  
X Ray Diffraction ◽  
Sintering Additive ◽  
Transmission Electron ◽  
High Annealing ◽  
Resolution Electron ◽  
Oxynitride Glass

Using a pure α–SiC starting powder and an oxynitride glass composition from the Y–Mg–Si–Al–O–N system as a sintering additive, a powder mixture was hot-pressed at 1850 °C for 1 h under a pressure of 20 MPa and further annealed at 2000 °C for 4 h in a nitrogen atmosphere of 0.1 MPa. High-resolution electron microscopy and x-ray diffraction studies confirmed that a small amount of β–SiC was observed in the liquid-phase-sintered α–SiC with this oxynitride glass, indicating stability of β–SiC even at high annealing temperature, due to the nitrogen-containing liquid phase.

Epitaxial Growth and Structure of Cubic and Pseudocubic Perovskite Films on Perovskite Substrates

1995 ◽  
Vol 401 ◽  
Author(s):  
P. A. Langjahr ◽  
T. Wagner ◽  
M. RÜhle ◽  
F. F. Lange
Keyword(s):  
Electron Microscopy ◽  
Epitaxial Growth ◽  
Lattice Mismatch ◽  
High Resolution Electron Microscopy ◽  
Lattice Parameter ◽  
Ternary Oxide ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Resolution Electron

AbstractCubic and pseudocubic perovskite films on perovskite substrates are used to study the influence of the lattice mismatch on the epitaxial growth of thin films on substrates of the same structure. For the growth of the films, a metalorganic decomposition route (MOD) using 2-ethylhexanoates and neodecanoates as precursors, was developed. The decomposition of the precursors was investigated with thermogravimetric analysis (TGA) and x-ray diffraction (XRD). The films were spin-coated on (001)-oriented SrTiO3- and LaAlO3-substrates, pyrolyzed and afterwards annealed between 600°C and 1200°C. XRD-nvestigations and conventional transmission electron microscopy (CTEM) show, that epitaxial films with the orientation relationship [100](001) film ║ [100](001) substrate can be grown. With XRD, it could be shown, that not only ternary oxide films (SrZrO3, BaZrO3 and BaCeO3), but also perovskite solid solution films (SrTi0.5Zr0.5O3and BaCe0.5Zr0.5O3) can be prepared. Strong interdiffusion, detected by a shift of the film lattice parameter towards the substrate lattice parameter was found in SrZrO3- and BaZrO3-films on SrTiO3, annealed at temperatures above 1050°C. High resolution electron microscopy (HREM) studies of SrZrO3 on SrTiO3 show that a crystalline semicoherent interface with a periodical array of misfit dislocations is present.

High-Resolution Electron Microscopy of C60 Clusters

1991 ◽  
Vol 49 ◽  
pp. 1024-1025
Author(s):  
M. M. Disko ◽  
S. K. Behal ◽  
R. D. Sherwood ◽  
F. Cosandey ◽  
P. Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Crystallization Rate ◽  
High Resolution Electron Microscopy ◽  
Single Type ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
New Information ◽  
Resolution Electron ◽  
Solvent Type ◽  
Carbon Molecules

Methods for the preparation of significant quantities of C60 clusters separated from carbon soot were recently reported by Krätschmer and co-workers. Evidence that these clusters have the “Buckminsterfullerene” structure with five-fold and six-fold carbon rings on the surface of a sphere (soccer-ball structure) has been provided by several techniques. NMR shows a single type of carbon bonding, and IR peaks consistent with modes characteristic of this system have been identified. Since C60 can be isolated and has stable “graphitic” bonding, it represents a unique opportunity to observe individual stable carbon molecules with transmission electron microscopy in order to test the morphology deduced from other techniques. Also, the study of packing sequences and defect structures in C60 crystals found by x-ray diffraction to have an FCC lattice constant of 1.41 nm provides important new information on variations of crystallization with conditions such as solvent type and crystallization rate.

Ultra Long SiCN Nanowires and SiCN/SiO2 Nanocables: Synthesis, Characterization, and Electrical Property

2008 ◽  
Vol 8 (12) ◽  
pp. 6338-6343
Author(s):  
K. F. Cai ◽  
L. Y. Huang ◽  
A. X. Zhang ◽  
J. L. Yin ◽  
H. Liu
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Argon Atmosphere ◽  
Quartz Tube ◽  
Catalyst Precursor ◽  
X Ray Diffraction ◽  
Polycrystalline Alumina ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Electron

SiCN nanowires are synthesized by pyrolysis of hexamethyldisilazane (HMDSN) using ferrocene as a catalyst precursor at 1200 °C in a flowing argon atmosphere on the surface of mullite substrate, polycrystalline alumina wafer and quartz tube. In oxygen-contained argon atmosphere, SiCN/SiO2 nanocables are synthesized. The as-synthesized products are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and high-resolution electron microscopy equipped with energy dispersive X-ray spectroscopy. The lengths of the nanowires and nanocables are in the millimeter range. The diameter of the SiCN nanowires grown on mullite substrate and alumina wafer ranges from about 10–70 nm, while that of the nanowires grown on quartz tube surface is in the range of around 7–10 nm. The diameters of the SiCN/SiO2 nanocables are relatively large. A vapor-liquid-solid growth mechanism of the nanostructures is proposed. The electrical resistivity of a single SiCN/SiO2 nanocable is reported for the first time.

New Insights on the Morphology of Nanocomposite Prepared by In Situ Emulsion Polymerization

2015 ◽  
Vol 775 ◽  
pp. 170-175
Author(s):  
José Costa de Macêdo Neto ◽  
João Evangelista Neto ◽  
Nayra Reis do Nascimento ◽  
Sheila Contant ◽  
Liliane Maria Ferrareso Lona
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Nanocomposite Powder ◽  
Thin Sections ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Level Of Details ◽  
High Level

In order to better understand the morphology and properties of polymer nanocomposites it is necessary to conduct their characterization by Transmission Electron Microscopy (TEM). This work shows a technique through which the nanocomposite powder is mixed with a resin, and after cured, thin sections can be obtained by ultramicrotomy. Another technique presented in this work deals with the observation of clay powder in solution. In this work High Resolution Electron Microscopy (HRTEM) was used to obtain images of the nanocomposites and clay. Images with a high level of details were showed. Through the use of such techniques, it was possible to observe two types of clay morphology in polymer matrix and its distribution. The dimensions and hexagonal layers of the natural clay used as nanofiller for the nanocomposite were also observed. The X-ray Diffraction (XRD) was used to investigate the kaolinite and nanocomposite.

scholarly journals Monoclinic superstructure in orthorhombic Ce10W22O81from transmission electron microscopy

2014 ◽  
Vol 70 (2) ◽  
pp. 268-274 ◽  
Author(s):  
Loïc Patout ◽  
Damien Jacob ◽  
Madjid Arab ◽  
Carlson Pereira de Souza ◽  
Christine Leroux
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Interstitial Oxygen ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Oxygen Ions ◽  
Transmission Electron ◽  
Resolution Electron

A complex rare-earth tungstate structure, present in a two-phased powder, was solved by electron diffraction, precession and high-resolution electron microscopy. The orthorhombic space groupPbnmand the atomic positions deduced from X-ray diffraction experiments were confirmed for Ce10W22O81. AC2/cmonoclinic superstructure, with cell parametersa= 7.8,b= 36.1,c= 22.2 Å and β = 100.2°, was shown and attributed to a partial oxidation of Ce3+leading to interstitial oxygen ions.

Highly Ordered and Well-oriented Single-crystal CdTe Nanowire Arrays by Direct-current Electrodeposition

2002 ◽  
Vol 17 (7) ◽  
pp. 1711-1714 ◽  
Author(s):  
Dongsheng Xu ◽  
Yuguo Guo ◽  
Dapeng Yu ◽  
Guolin Guo ◽  
Youqi Tang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
High Resolution Electron Microscopy ◽  
Growth Direction ◽  
Nanowire Arrays ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Anodic Aluminum Oxide Templates ◽  
Oriented Single Crystal

Highly ordered CdTe nanowire arrays were prepared by electrochemical deposition into the pores of anodic aluminum oxide templates from an ethylene glycol bath containing CdCl2, TeCl4, and KI. Electron microscopy results showed that the length, diameter, and direction of growth of the nanowires were quite uniform. X-ray diffraction, transmission electron microscopy, and high-resolution electron microscopy investigations showed that these nanowires had a crystalline structure of hexagonal CdTe single crystal with a uniform [001] growth direction.

Interface structures in polycrystalline ceramic materials

1986 ◽  
Vol 44 ◽  
pp. 468-471
Author(s):  
K. J. Morrissey
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Physical And Mechanical Properties ◽  
High Resolution Electron Microscopy ◽  
Ceramic Materials ◽  
Polycrystalline Materials ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Interface Structures

Grain boundaries and interfaces play an important role in determining both physical and mechanical properties of polycrystalline materials. To understand how the structure of interfaces can be controlled to optimize properties, it is necessary to understand and be able to predict their crystal chemistry. Transmission electron microscopy (TEM), analytical electron microscopy (AEM,), and high resolution electron microscopy (HREM) are essential tools for the characterization of the different types of interfaces which exist in ceramic systems. The purpose of this paper is to illustrate some specific areas in which understanding interface structure is important. Interfaces in sintered bodies, materials produced through phase transformation and electronic packaging are discussed.

High Resolution Transmission Electron Microscopy of an automobile catalytic converter

1990 ◽  
Vol 48 (4) ◽  
pp. 242-243
Author(s):  
Jan-Olle Malm ◽  
Jan-Olov Bovin
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Catalytic Converter ◽  
Active Material ◽  
Image Intensifier ◽  
High Resolution Electron Microscopy ◽  
Detailed Knowledge ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Atomic Surface

Understanding of catalytic processes requires detailed knowledge of the catalyst. As heterogeneous catalysis is a surface phenomena the understanding of the atomic surface structure of both the active material and the support material is of utmost importance. This work is a high resolution electron microscopy (HREM) study of different phases found in a used automobile catalytic converter.The high resolution micrographs were obtained with a JEM-4000EX working with a structural resolution better than 0.17 nm and equipped with a Gatan 622 TV-camera with an image intensifier. Some work (e.g. EDS-analysis and diffraction) was done with a JEM-2000FX equipped with a Link AN10000 EDX spectrometer. The catalytic converter in this study has been used under normal driving conditions for several years and has also been poisoned by using leaded fuel. To prepare the sample, parts of the monolith were crushed, dispersed in methanol and a drop of the dispersion was placed on the holey carbon grid.

Structure of InAs Quantum Dots in Si Matrix Investigated by High Resolution Electron Microscopy

1999 ◽  
Vol 571 ◽  
Author(s):  
N. D. Zakharov ◽  
P. Werner ◽  
V. M. Ustinov ◽  
A.R. Kovsh ◽  
G. E. Cirlin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Critical Thickness ◽  
High Resolution Electron Microscopy ◽  
Geometrical Parameters ◽  
Inas Quantum Dots ◽  
Temperature Growth ◽  
Transmission Electron ◽  
Resolution Electron

ABSTRACTQuantum dot structures containing 2 and 7 layers of small coherent InAs clusters embedded into a Si single crystal matrix were grown by MBE. The structure of these clusters was investigated by high resolution transmission electron microscopy. The crystallographic quality of the structure severely depends on the substrate temperature, growth sequence, and the geometrical parameters of the sample. The investigation demonstrates that Si can incorporate a limited volume of InAs in a form of small coherent clusters about 3 nm in diameter. If the deposited InAs layer exceeds a critical thickness, large dislocated InAs precipitates are formed during Si overgrowth accumulating the excess of InAs.

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