The Formation Mechanism of Carrot Defects in SiC Epifilms

2006 ◽  
Vol 911 ◽  
Author(s):  
Hui Chen ◽  
Guan Wang ◽  
Yi Chen ◽  
Xiaoting Jia ◽  
Jie Bai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Mechanism Of Formation ◽  
Cross Sectional ◽  
Screw Dislocations ◽  
X Ray ◽  
Transmission Electron ◽  
Sic Wafer ◽  
Scanning Electron

AbstractCarrot-like defects in a 7&#61616; off-cut (from [0001] toward <1-210> direction) 4H-SiC wafer with a 36μm thick 4H-SiC epilayer have been investigated using Nomarski optical microscopy, synchrotron white beam x-ray topography (SWBXT), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray topographs confirm that threading screw dislocations are often associated with the carrots. Cross-sectional TEM observation confirms that a prismatic stacking fault exists below the carrot. This fault was found to show contrast in all observed diffraction geometries except for g=0004. A model for the mechanism of formation of this type of defect during epitaxial growth is proposed.

Hydrothermal Synthesis and Characterization of BiFeO3 Polyhedral Crystallites

2012 ◽  
Vol 174-177 ◽  
pp. 508-511
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.

Influence of Salt Aid on Combustion Synthesis of Nanocrystalline CeO2 Powders

2011 ◽  
Vol 412 ◽  
pp. 5-8 ◽  
Author(s):  
Ying Zhang ◽  
Ai Chen ◽  
Hai Rong Wang ◽  
Ze Song Li ◽  
Ying Ping Shen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Combustion Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Particle Characteristics ◽  
Transmission Electron ◽  
Nanocrystalline Ceria ◽  
Scanning Electron

The present article reports the results of studies related to the synthesis of nanocrystalline ceria powder by combustion process using salt combustion aid. Cerium nitrate as oxidant and urea as fuel were used as reagents, Sodium Chloride was compared as combustion aid. The phase analysis and particle size were compared. The product was characterized by X-ray diffraction, Scanning electron microscopy and Transmission electron microscopy. The results showed that employment of starting fuel with combustion aid resulted in synthesizing nanocrystalline ceria powder with fine agglomerates. By using combustion aid, the energetics of the combustion reaction and particle characteristics have been changed.

Analyse des Stuckgipses der Abtei Villers / Analysis of Stucco from the Abbey of Villers

1997 ◽  
Vol 3 (4) ◽  
pp. 381-396
Author(s):  
S. Chandra ◽  
D. Van Gemert
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Analysis ◽  
Electron Spectroscopy ◽  
Natural Polymer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Abstract Interior plaster from the Abbot's Palace of the Abbey of Villers-la-Ville, Brabant Wallon province, Belgium has been investigated. It is done by using chemical analysis, x-ray diffraction analysis, scanning electron microscopy, energy dispersive electron spectroscopy, and transmission electron microscopy. It is found that the rendering was made with lime rich mortar and animal hairs. The sand used was very fine and the hairs were very short. The solid constituents and the hairs were uniformly dispersed, which could have been obtained by the addition of some other natural polymer, containing protein.

Controlled Synthesize of BaTiO3 Nanoparticles and BaCO3 Nanowires through the Reverse Micelle System

2009 ◽  
Vol 66 ◽  
pp. 171-174
Author(s):  
Zhao Deng ◽  
Ying Dai ◽  
Wen Chen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Composition ◽  
Reverse Micelle ◽  
X Ray ◽  
Transmission Electron ◽  
Batio3 Nanoparticles ◽  
Scanning Electron ◽  
Micelle System

Single-crystalline BaTiO3 nanoparticles and BaCO3 nanowires were synthesized respectively through the use of a reverse micelle as a medium in the same Oleic acid/n-octane/H2O system, by changing the H2O2 dosage. Both the phase composition and the morphology can be controled. The samples derived were characterized with X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The formation mechanism has been fully discussed.

Study of Hydrothermal Synthesis of Ce0.67Zr0.33O2 Nanorods and Catalytic Property to CO

2011 ◽  
Vol 347-353 ◽  
pp. 615-620
Author(s):  
Ying Jia ◽  
Tian Tian Liu ◽  
Cheng Luo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Catalytic Oxidation ◽  
Zirconium Oxychloride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Three Way Catalyst ◽  
Scanning Electron

Ce0.67Zr0.33O2 (CZ) nanorods are successfully synthesized by glycol-assisted hydrothermal method using zirconium oxychloride, cerium nitrate and urea, with the presence of sodium hypochlorite. The products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectra. The catalytic oxidation characters about Pd/CZ three-way catalyst (TWC) prepared with different loads of Pd are also investigated. The results show that the as-prepared Pd/CZ has excellent catalytic oxidation character to CO.

Synthesis of ZnO with Different Morphology and its Photocatalytic Property

2011 ◽  
Vol 110-116 ◽  
pp. 547-552 ◽  
Author(s):  
Yu Xin Wang ◽  
Jing Xu ◽  
Xing Guo Cheng ◽  
Hong Fang Xu ◽  
Li Jun Liu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photocatalytic Property ◽  
Zno Nanostructures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Zno Nanomaterials ◽  
Scanning Electron

ZnO nanostructures with different morphology have been successfully fabricated by a simple relative low temperature approach at 90 °C for 5 h without surfactant assistance. These structures can be easily tailed using varied concentrations of sodium hydroxide (NaOH) and different amounts of the hydrazine hydrate (N2H4·H2O). X-ray diffraction (XRD) result proves the formation of ZnO with wurtzite structure. Microstructure as revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicates that the rod-like and chrysanthemum-like ZnO nanostructures contain many radial nanorods, which grow along the [0001] direction. Furthermore, the as-prepared ZnO nanomaterials exhibit high activity on the photo-catalytic degradation of typical persistent organic pollutants (POPs), indicating that they are promising as semiconductor photo-catalysts.

Synthesis of Iron Oxide Nanowires by Heating Iron Foils

2007 ◽  
Vol 342-343 ◽  
pp. 597-600
Author(s):  
Hyoun Woo Kim ◽  
S.H. Shim ◽  
B.H. O ◽  
S.G. Lee ◽  
S.G. Park ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Iron Oxide ◽  
Diffraction Pattern ◽  
Growth Mechanisms ◽  
Oxide Nanowires ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

We have fabricated the iron oxide nanowires directly from iron foils through the simple heating in N2 ambient. We have characterized the samples by means of scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray (EDX) spectroscopy, and selected area diffraction pattern. The EDX spectrum revealed that the nanowires contained elements of Fe and O. The iron oxide nanowires were crystalline with diameters in the range of 30-200 nm. We have discussed the possible growth mechanisms.

Localization of Silver in the Spleen of Argyric Rats by Energy Dispersive X-Ray Analysis Coupled with Scanning and Transmission Electron Microscopy

1977 ◽  
Vol 35 ◽  
pp. 504-506
Author(s):  
G. Pereira
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Computer Assisted ◽  
White Pulp ◽  
Reticular Cell ◽  
X Ray ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Previous electron microscopic observations of the spleen have revealed the white pulp to be completely separated from the extravasated blood in the surrounding marginal zone by a strategically-located, double layer of reticular cells ensheathing a coarse reticular fiber. Similarly, a single reticular cell layer has been observed to form a continuous investment for all white pulp capillaries. To test the significance of this apparent isolation of the splenic white pulp from the blood, the distribution and composition of silver deposits in the spleen of argyric rats were determined by transmission and scanning electron microscopy coupled with computer-assisted x-ray analysis.Young male albino rats were made argyric by supplying them for many months with drinking water to which 1.5gm per liter of silver nitrate had been added. Specimens from the spleens of control and argyric animals were prepared for conventional transmission electron microscopy by glutaraldehyde-osmium fixation. For scanning electron microscopy, other specimens were fixed in buffered glutaraldehyde, freeze-dried in vacuo, coated with a thin film of gold- palladium and examined in a Cambridge Stereoscan Mark II.

Nanostructured CaWO4, CaWO4:Eu3+ and CaWO4:Tb3+ Particles: Sonochemical Synthesis and Luminescent Properties

2008 ◽  
Vol 8 (3) ◽  
pp. 1183-1190 ◽  
Author(s):  
Chunxia Li ◽  
Cuikun Lin ◽  
Xiaoming Liu ◽  
Jun Lin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Field Emission ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Nanostructured CaWO4, CaWO4:Eu3+, and CaWO4:Tb3+ phosphor particles were synthesized via a facile sonochemical route. X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence, low voltage cathodoluminescence spectra, and photoluminescence lifetimes were used to characterize the as-obtained samples. The X-ray diffraction results indicate that the samples are well crystallized with the scheelite structure of CaWO4. The transmission electron microscopy and field emission scanning electron microscopy images illustrate that the powders consist of spherical particles with sizes from 120 to 160 nm, which are the aggregates of even smaller nanoparticles ranging from 10 to 20 nm. Under UV light or electron beam excitation, the CaWO4 powder exhibited a blue emission band with a maximum at 430 nm originating from the WO2−4 groups, while the CaWO4:Eu3+ powder showed red emission dominated by 613 nm ascribed to the 5D0 → 7F2 of Eu3+, and the CaWO4:Tb3+ powders showed emission at 544 nm, ascribed to the 5D4 → 7F5 transition of Tb3+. The PL excitation and emission spectra suggest that the energy is transferred from WO2−4 to Eu3+CaWO4:Eu3+ and to Tb3+ in CaWO4:Tb3+. Moreover, the energy transfer from WO2−4 to Tb3+ in CaWO4:Tb3+ is more efficient than that from WO2−4 to Eu3+ in CaWO4:Eu3+. This novel and efficient pathway could open new opportunities for further investigating the novel properties of tungstate materials.

INFLUENCE OF AMMONIATING TIME ON Nb-CATALYZED GaN NANOSTRUCTURED MATERIALS

2011 ◽  
Vol 10 (06) ◽  
pp. 1209-1214 ◽  
Author(s):  
HUIZHAO ZHUANG ◽  
JIE WANG ◽  
XIAOKAI ZHANG ◽  
JUNLIN LI
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nanostructured Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Turn On ◽  
Transmission Electron ◽  
Morphology And Structure ◽  
Scanning Electron

Gallium nitride ( GaN ): nanostructured materials are synthesized by ammoniating Ga2O3/Nb films which are deposited in turn on Si(111) substrates at 900°C. The morphology and structure of the nanostructured materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Optical property of GaN nanostructured materials are analyzed by photoluminescence (PL). The results demonstrated that as-synthesized nanostructured materials are hexagonal wurtzite-structured. Ammoniating time of the samples has an evident influence on the morphology of GaN nanostructured materials synthesized by this method. The PL spectra indicate good emission property for the nanostructured materials. Finally, the growth mechanism is also briefly discussed.

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