Selective growth and characterization of nanostructures with transmission electron microscopes

2005 ◽  
Vol 241 (1-2) ◽  
pp. 56-60 ◽  
Author(s):  
M. Shimojo ◽  
S. Bysakh ◽  
K. Mitsuishi ◽  
M. Tanaka ◽  
M. Song ◽  
...  
Keyword(s):  
Selective Growth ◽  
Transmission Electron ◽  
Electron Microscopes

An Environmental Transmission Electron Microscope for in situ Synthesis and Characterization of Nanomaterials

2005 ◽  
Vol 20 (7) ◽  
pp. 1695-1707 ◽  
Author(s):  
Renu Sharma
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Elevated Temperatures ◽  
Dark Field ◽  
In Situ Synthesis ◽  
Synthesis And Characterization ◽  
Transmission Electron ◽  
Electron Microscopes

The world of nanomaterials has become the real world for most applications in the area of nanotechnology. As postsynthesis handling of materials at the nanoscale level is impractical, nanomaterials must be synthesized directly as part of a device or circuit. The demands of nanotechnology have led to modifications in the design of transmission electron microscopes (TEMs) that enable in situ synthesis and characterization simultaneously. The environmental TEM (ETEM) is one such modified instrument that has often been used to follow gas–solid and/or liquid–solid interactions at elevated temperatures. Although the history and development of the ETEM, also called the controlled atmosphere or environmental cell TEM, is as old as transmission electron microscopy itself, developments in the design of medium-voltage TEMs have succeeded in bringing resolutions down to the subnanometer level. A modern ETEM equipped with a field-emission gun, energy filter or electron energy-loss spectrometer, scanning transmission electron microscopy coils, and bright-field and dark-field detectors can be a versatile tool for understanding chemical processes at the nanometer level. This article reviews the design and operations of a dedicated ETEM. Its applications range from the in situ characterization of reaction steps, such as oxidation-reduction and hydroxylation, to the in situ synthesis of nanomaterials, such as quantum dots and carbon nanotubes. Some examples of the current and the future applications for the synthesis and characterization of nanomaterials are also discussed.

scholarly journals Characterization of Heterogeneous Catalysts in Different Environmental Transmission Electron Microscopes at 80kV to 1MV Accelerating Voltage

2011 ◽  
Vol 17 (S2) ◽  
pp. 1706-1707
Author(s):  
K Yoshida ◽  
A Carlsson ◽  
J Jinschek ◽  
D Stokes ◽  
P Gai ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Environmental Transmission ◽  
Transmission Electron ◽  
Electron Microscopes

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

High-Resolution TEM and the Application of Direct and Indirect Aberration Correction

2008 ◽  
Vol 14 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Crispin J.D. Hetherington ◽  
Lan-Yun Shery Chang ◽  
Sarah Haigh ◽  
Peter D. Nellist ◽  
Lionel Cervera Gontard ◽  
...  
Keyword(s):  
Substantial Improvement ◽  
Confocal Imaging ◽  
Aberration Correction ◽  
Indirect Methods ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Imaging Mode ◽  
Electron Microscopes ◽  
Direct And Indirect Methods

Aberration correction leads to a substantial improvement in the directly interpretable resolution of transmission electron microscopes. Correction of the aberrations has been achieved electron-optically through a hexapole-based corrector and also indirectly by computational analysis of a focal or tilt series of images. These direct and indirect methods are complementary, and a combination of the two offers further advantages. Materials characterization has benefitted from the reduced delocalization and higher resolution in the corrected images. It is now possible, for example, to locate atomic columns at surfaces to higher accuracy and reliability. This article describes the JEM-2200FS in Oxford, which is equipped with correctors for both the image-forming and probe-forming lenses. Examples of the use of this instrument in the characterization of nanocrystalline catalysts are given together with initial results combining direct and indirect methods. The double corrector configuration enables direct imaging of the corrected probe, and a potential confocal imaging mode is described. Finally, modifications to a second generation instrument are outlined.

Structural Characterization of InAlAs/InGaAs Layers Grown on InP Patterned Substrates

1994 ◽  
Vol 340 ◽  
Author(s):  
F. Peiro ◽  
A. Cornet ◽  
J.R. Morante ◽  
K. Zekentes ◽  
A. Georgakilas
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Characterization ◽  
Growth Habit ◽  
Selective Growth ◽  
Patterned Substrates ◽  
Polycrystalline Layer ◽  
Transmission Electron ◽  
Inp Substrates

ABSTRACTIn this work we present structural characterization by both Scanning and Transmission Electron Microscopy of InAlAs/InGaAs heterostructures grown on InP substrates. Our attention is devoted to study the two main problems limiting the application of these structures as devices: the presence of defects on the epilayer and the growth habit at theedges of the well. Our results show that a different faceting between the two <110> orthogonal directions develops during the growth and that a high density of defects is observed just at the intersection between the layers grown inside the windows and on the walls. Moreover, the presence of a polycrystalline layer developing over the mask indicates that a selective growth occurs.

Atomic Scale Characterization Of Interfaces And Defects In Non-Stoichiometricmulticomponent Oxides

1999 ◽  
Vol 5 (S2) ◽  
pp. 106-107
Author(s):  
S. Stemmer ◽  
S. K. Streiffer ◽  
A. Sane ◽  
T. J. Mazanec ◽  
N. D. Browning
Keyword(s):  
Dark Field ◽  
Atomic Scale ◽  
Chemical Information ◽  
Structure Property ◽  
Contrast Imaging ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Scale Characterization ◽  
Electron Microscopes

The ability to obtain chemical information with (near) atomic resolution has recently become possible by a combined approach of Z-contrast imaging with electron energy-loss spectroscopy (EELS) in scanning transmission electron microscopes. This method is particularly interesting for the characterization of structure-property relationships in novel multicomponent oxides, which possess added functionality due to their high nonstoichiometry.In this paper we demonstrate the capabilities of this method in analyzing the microstructural mechanisms of accommodation of non-stoichiometry, using two example systems: (Ba,Sr)TiO3thin films for DRAM applications, grown by MOCVD with different amounts of excess titanium, and an oxygen-deficient perovskite ceramic, SrCoOx. The experiments were performed in a JEOL JEM 201 OF field emission transmission electron microscope, operating at 200 kV, equipped with an annular dark-field detector, scanning unit and a post-column imaging filter (Gatan GIF 200). This microscope has been demonstrated to achieve probe sizes of under 1.5 Å .

scholarly journals Characterization of Sulfur and Nanostructured Sulfur Battery Cathodes in Electron Microscopy Without Sublimation Artifacts

2017 ◽  
Vol 23 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Barnaby D.A. Levin ◽  
Michael J. Zachman ◽  
Jörg G. Werner ◽  
Ritu Sahore ◽  
Kayla X. Nguyen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Vacuum ◽  
Lithium Ion ◽  
Multiple Length Scales ◽  
Transmission Electron ◽  
Nanoscale Characterization ◽  
Infusion Method ◽  
Electron Microscopes ◽  
Sulfur Battery

AbstractLithium sulfur (Li–S) batteries have the potential to provide higher energy storage density at lower cost than conventional lithium ion batteries. A key challenge for Li–S batteries is the loss of sulfur to the electrolyte during cycling. This loss can be mitigated by sequestering the sulfur in nanostructured carbon–sulfur composites. The nanoscale characterization of the sulfur distribution within these complex nanostructured electrodes is normally performed by electron microscopy, but sulfur sublimates and redistributes in the high-vacuum conditions of conventional electron microscopes. The resulting sublimation artifacts render characterization of sulfur in conventional electron microscopes problematic and unreliable. Here, we demonstrate two techniques, cryogenic transmission electron microscopy (cryo-TEM) and scanning electron microscopy in air (airSEM), that enable the reliable characterization of sulfur across multiple length scales by suppressing sulfur sublimation. We use cryo-TEM and airSEM to examine carbon–sulfur composites synthesized for use as Li–S battery cathodes, noting several cases where the commonly employed sulfur melt infusion method is highly inefficient at infiltrating sulfur into porous carbon hosts.

Parallel EELS as a complementary tool in an Analytical TEM study of metal alloys

1991 ◽  
Vol 49 ◽  
pp. 612-613
Author(s):  
R.E. Guerra ◽  
E.G. Rightor
Keyword(s):  
Polished Surface ◽  
Ion Milling ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Thin Foils ◽  
Transmission Electron ◽  
Common Ion ◽  
Electron Microscopes ◽  
Electron Energy Loss

The advent of efficient parallel-detection electron energy loss spectrometers (EELS) in analytical transmission electron microscopes (ATEM) promotes rapid elemental characterization of various materials containing light, as well as heavy, elements at high spatial resolution. In the current study, the microstructures of Udimet 520 and HK-25 were investigated to integrate advances in parallel EELS methods with other ATEM techniques.Thin foils of Udimet 520, a nickel based heat-resistant superalloy, were obtained using common ion milling techniques. Precipitates of the HK-25, a heat resistant steel alloy, were obtained by etching (with Marble's reagent) a polished surface, extracting with a replicating Parlodian film, dissolving the film with amyl acetate and dispersing the resulting particles on holey carbon grids. A JEOL 2000FX ATEM fitted with a Gatan Model 666 EELS system was operated at 200 kV for studies of these alloys.

Characterization of small inclusions: SEM vs TEM, or is it even worth considering Sem?

1996 ◽  
Vol 54 ◽  
pp. 498-499
Author(s):  
Carl Blais ◽  
Gilles L’Espérance ◽  
Éric Baril ◽  
Clément Forget
Keyword(s):  
Chemical Composition ◽  
X Rays ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Diffraction Patterns ◽  
Micro Alloyed Steel ◽  
Steel Welds ◽  
Scanning Electron Microscopes

Inclusions of technological importance are often in the size range from 0.1 to 1 μm, These inclusions are generally too thick for EEL-spectrometry and require the use of EDS to characterize their chemical composition. Recent Monte Carlo simulations indicated that scanning electron microscopes (SEM’s) equiped with a field emission gun (FEG) might challenge transmission electron microscopes (TEM’s) for the charaterization of small inclusions, In the light of these results, we investigated the possibility of using a FEGSEM to characterize inclusions found in micro-alloyed steel welds used for arctic applications. The main setbacks of using EDS for such a task are due to the presence of small phases of unknown thicknesses, non-homogeneity of the X-ray generation volumes, variation in absorption along the path length of the X-rays, etc., Even though these problems are encoutered in both the SEM and the TEM, the relative ease of imaging the very small inclusions in TEM confers a definite advantage to this technique. Furthermore, TEM allows to obtain convergent-bearn electron diffraction patterns (CBED) which complement the chemical composition characterization, thereby allowing the unambiguous identification of the phases present (chemistry and crystal structure).

scholarly journals Analysis of airborne metal containing particles with EDX/EDS detectors in electron microscopes

2011 ◽  
Vol 9 (2) ◽  
pp. 308-313 ◽  
Author(s):  
Przemysław Sielicki ◽  
Helena Janik ◽  
Agnieszka Guzman ◽  
Alan Reynolds ◽  
Jacek Namieśnik
Keyword(s):  
Particulate Matter ◽  
Electron Microscope ◽  
Major Element ◽  
X Ray ◽  
Minor Elements ◽  
Particle Population ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Scanning Electron

AbstractIn years 2006–2010 particulate matter analysis was undertaken for dust samples collected from Gdansk and London area in order to compare their morphology and composition. Part of those studies was devoted to analysis of particulate matter (PM) bearing metals. Characterization of the morphology and size of the particles collected onto the filters was performed using a scanning electron microscope (SEM) and transmission electron microscope (TEM). Both electron microscopes were equipped with energy dispersive X-ray spectrometers to identify the elemental composition of the particles. On analysis of the X-ray spectra acquired by both TEM and SEM, the particles were divided into 10 groups as follows: Al-rich, Ba-rich, C-rich, Ca-rich, Cl-rich, Fe-rich, Mg-rich, Na-rich, S-rich, Si-rich. Speciation of the particles based on the major element and accompanying minor elements yielded 34 particle types. However, some pairs of elements repeat, for instance: Na-Cl and Cl-Na, Al-S and S-Al, Si-Al and Al-Si, S-Ca and Ca-S. These are undoubtedly the same types of particles; variation in peak heights of the major and minor elements is normal in a mixed particle population.

Characterization of Interfaces in SiC Particulate-Reinforced Al Alloys by AEM

1989 ◽  
Vol 170 ◽  
Author(s):  
Brian W. Robertson ◽  
Chandra Holm ◽  
Yang-Pi Lin ◽  
Stephen F. J. Corbin ◽  
David S. Wilkinson
Keyword(s):  
Sample Preparation ◽  
Silicon Content ◽  
Al Alloys ◽  
Preliminary Step ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Particulate Reinforced

AbstractAs a preliminary step to detailed study of the interfaces in SiC particulatereinforced Al alloys, a number of methods of sample preparation have been explored; the resultant artefacts on the thinned foils observed in transmission electron microscopes are discussed and improvements to the preparation procedures are suggested. Initial observations of the microstructure of two alloys differing significantly in their matrix silicon content are presented.

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