scholarly journals Formation of Au/Pd Alloy Nanoparticles on TMV

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Jung-Sun Lim ◽  
Seung-Min Kim ◽  
Sang-Yup Lee ◽  
Eric A. Stach ◽  
James N. Culver ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Genetically Engineered ◽  
Solid Solution Alloy ◽  
Alloy Formation ◽  
Alloy Nanoparticles ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Pd Alloy ◽  
Electron Energy Loss

A gold-palladium (AuPd) solid solution alloy was successfully deposited on the genetically engineered tobacco mosaic virus (TMV1Cys) by the biosorption of Au(III) and Pd(II) precursors and the reduction of the Au(III) and Pd(II) to their respective metals or metal alloy. The resulting morphologies of alloy nanoparticles deposited on the TMV1Cys were observed with transmission electron microscopy (TEM), and the AuPd alloy formation was supported with surface plasmon resonance (SPR) and selected area electron diffraction (SAED). In addition, selected alloy nanoparticles on the TMV1Cys were analyzed further with electron energy loss spectroscopy (EELS) to confirm the presence of gold and palladium. Our result implies that biotemplated metal mineralization is a potentially useful methodology to prepare alloy nanoparticles.

Orientation relationship and interfacial structure between Nbsolid solution precipitates and α-Nb5Si3 intermetallics

2009 ◽  
Vol 24 (1) ◽  
pp. 192-197 ◽  
Author(s):  
G.M. Cheng ◽  
Y.X. Tian ◽  
L.L. He
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Transmission Electron Microscopy ◽  
Stress Concentration ◽  
High Resolution ◽  
Orientation Relationship ◽  
Interfacial Structure ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
High Resolution Tem

The orientation relationship (OR) and the interfacial structure between Nb solid solution (Nbss) precipitates and α-Nb5Si3 intermetallics have been investigated by transmission electron microscopy (TEM). The OR between Nbss and α-Nb5Si3 was determined by selected-area electron diffraction analyses as (222)Nb//(002)α and . High-resolution TEM images of the Nbss/α-Nb5Si3 interface were presented. Steps existed at the interface that acted as centers of stress concentration and released the distortion of lattices to decrease the interfacial energy. In addition, the interfacial models were proposed based on the observed OR to describe the atomic matching of the interface. The distribution of alloying elements at the Nbss/α-Nb5Si3 interface has also been investigated, and Hf was enriched at the interface to strengthen the grain boundary.

Increased Ordering in the Amorphous SiOx due to Hyperthermal Atomic Oxygen.

2004 ◽  
Vol 851 ◽  
Author(s):  
Maja Kisa ◽  
William G. Stratton ◽  
Timothy K. Minton ◽  
Klaus van Benthem ◽  
Steve J. Pennycook ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Diffraction Pattern ◽  
Molecular Oxygen ◽  
Atomic Oxygen ◽  
Structural Characteristics ◽  
Silica Layer ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Electron Energy Loss

ABSTRACTWe had studied the effects of hyperthermal (5.1eV) atomic oxygen (AO) on the structural characteristics of the silica layer and Si/SiOx interface formed by the oxidation of Si-single crystal by a variety of microcharacterization techniques. A laser detonation source was used to produce atomic oxygen with 5.1eV kinetic energy. High Resolution Transmission Electron Microscopy (HRTEM) and Selected Area Electron Diffraction (SAED) demonstrated that the silica layer formed on Si(100) by atomic oxygen is thicker, more homogeneous, and less amorphous, compared to the oxide layer created by molecular oxygen (MO). High spatial resolution Electron Energy Loss Spectroscopy (EELS) study confirmed that the Si/SiOx interface created by atomic oxygen is abrupt containing no suboxides as opposed to the broad interface with transitional states formed by molecular oxygen. SAED technique was used to observe sharper diffraction rings present in the diffraction pattern of Si(100) oxidized by reactive atomic oxygen as opposed to the diffused haloes present in the diffraction pattern of Si(100) oxidized by molecular oxygen. Radial Distribution Function (RDF) analyses were performed on the SAED patterns of Si(100) oxidized in atomic and molecular oxygen, indicating that a more ordered oxide is formed by atomic oxygen. Initial Fluctuation Electron Microscopy (FEM) results confirmed an increased medium range ordering in SiOx formed by atomic oxygen when compared to the non-regular arrangement present in the amorphous oxide formed by the oxidation of Si(100) in molecular oxygen.

A Transmission Electron Microscopy Study of Fe-Co Alloy Nanoparticles in Silica Aerogel Matrix Using HREM, EDX, and EELS

2009 ◽  
Vol 15 (2) ◽  
pp. 114-124 ◽  
Author(s):  
Andrea Falqui ◽  
Anna Corrias ◽  
Mhairi Gass ◽  
Gavin Mountjoy
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Alloy Nanoparticles ◽  
Transmission Electron ◽  
Electron Energy Loss ◽  
Microscopy Images

AbstractMagnetic nanocomposite materials consisting of 5.5 wt% Fe-Co alloy nanoparticles in a silica aerogel matrix, with compositions FexCo1−x of x = 0.50 and 0.67, have been synthesized by the sol-gel method. The high-resolution transmission electron microscopy images show nanoparticles consisting of single crystal grains of body-centered cubic Fe-Co alloy, with typical crystal grain diameters of approximately 4 and 7 nm for Fe0.5Co0.5 and Fe0.67Co0.33 samples, respectively. The energy dispersive X-ray (EDX) spectra summed over areas of the samples gave compositions FexCo1−x with x = 0.48 ± 0.06 and 0.68 ± 0.05. The EDX spectra obtained with the 1.5 nm probe positioned at the centers of ∼20 nanoparticles gave slightly lower concentrations of Fe, with means of ⟨x⟩ = 0.43 ± 0.01 and ⟨x⟩ = 0.64 ± 0.02, respectively. The Fe0.5Co0.5 sample was studied using electron energy loss spectroscopy (EELS), and EELS spectra summed over whole nanoparticles gave x = 0.47 ± 0.06. The EELS spectra from analysis profiles of nanoparticles show a distribution of Fe and Co that is homogeneous, i.e., x = 0.5, within a precision of at best ±0.05 in x and ±0.4 nm in position. The present microscopy results have not shown the presence of a thin layer of iron oxide, but this might be at the limit of detectability of the methods.

Deposition And Characterization Of Silicon And Carbon Nitride

1995 ◽  
Vol 410 ◽  
Author(s):  
A. F. Myers ◽  
D. A. Tucker ◽  
S. P. Bozeman ◽  
S. M. Camphausen ◽  
M. J. Powers ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
Carbon Nitride ◽  
Nitrogen Plasma ◽  
Inductively Coupled ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Electron Energy Loss

ABSTRACTWe attempted to deposit carbon nitride films on flat Si (111) substrates and on sharp <111>-oriented silicon needles in a radio frequency (rf) inductively coupled plasma system utilizing a graphite source and a nitrogen plasma. The resultant polycrystalline films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Auger electron spectroscopy (AES), and electron energy loss spectroscopy (EELS). Both selected area electron diffraction (SAED) and lattice imaging were used to identify and characterize the particles, which grew as faceted crystals up to 1 Rm in size. From SAED, high resolution TEM, and EELS, it was found that the particles on the Si needles were α-Si3N4 and that those on the Si wafer were mostly β-Si3N4 and β-C3N4, with some β-C3N4 possible. Auger quantitative analysis suggests that β-C3N4 could be stabilized by the presence of silicon, resulting in a material with compositions CxSiyNz.

High-resolution EM study of submicrometer-grained Al-Mg solid solution alloys

1995 ◽  
Vol 53 ◽  
pp. 524-525
Author(s):  
Z. Horita ◽  
D. J. Smith ◽  
M. Furukawa ◽  
M. Nemoto ◽  
R. Z. Valiev ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
High Resolution ◽  
Grain Boundaries ◽  
Energy State ◽  
High Energy ◽  
Grain Structure ◽  
Boundary Structure ◽  
Solid Solution Alloy ◽  
Average Grain Size

It is possible to produce metallic materials with submicrometer-grained (SMG) structures by imposing an intense plastic strain under quasi-hydrostatic pressure. Studies using conventional transmission electron microscopy (CTEM) showed that many grain boundaries in the SMG structures appeared diffuse in nature with poorly defined transition zones between individual grains. The implication of the CTEM observations is that the grain boundaries of the SMG structures are in a high energy state, having non-equilibrium character. It is anticipated that high-resolution electron microscopy (HREM) will serve to reveal a precise nature of the grain boundary structure in SMG materials. A recent study on nanocrystalline Ni and Ni3Al showed lattice distortion and dilatations in the vicinity of the grain boundaries. In this study, HREM observations are undertaken to examine the atomic structure of grain boundaries in an SMG Al-based Al-Mg alloy.An Al-3%Mg solid solution alloy was subjected to torsion straining to produce an equiaxed grain structure with an average grain size of ~0.09 μm.

Investigation of Switching Mechanism in HfO2-Based Oxide Resistive Memories by In-Situ Transmission Electron Microscopy and Electron Energy Loss Spectroscopy

2017 ◽  
Author(s):  
T. Dewolf ◽  
D. Cooper ◽  
N. Bernier ◽  
V. Delaye ◽  
A. Grenier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Hafnium Dioxide ◽  
Switching Mechanism ◽  
Transmission Electron ◽  
Electron Energy Loss

Abstract Forming and breaking a nanometer-sized conductive area are commonly accepted as the physical phenomenon involved in the switching mechanism of oxide resistive random access memories (OxRRAM). This study investigates a state-of-the-art OxRRAM device by in-situ transmission electron microscopy (TEM). Combining high spatial resolution obtained with a very small probe scanned over the area of interest of the sample and chemical analyses with electron energy loss spectroscopy, the local chemical state of the device can be compared before and after applying an electrical bias. This in-situ approach allows simultaneous TEM observation and memory cell operation. After the in-situ forming, a filamentary migration of titanium within the dielectric hafnium dioxide layer has been evidenced. This migration may be at the origin of the conductive path responsible for the low and high resistive states of the memory.

scholarly journals Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

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