Removing Substrate Background in TEM Microanalysis

1974 ◽  
Vol 32 ◽  
pp. 568-569
Author(s):  
John C. Russ ◽  
Nicholas C. Barbi
Keyword(s):  
Electrical Conductivity ◽  
Rapid Growth ◽  
Organic Film ◽  
Absolute Concentration ◽  
Background Signal ◽  
X Ray ◽  
Elemental Concentrations ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
The Continuum

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.

Transmission electron microscope studies in special ceramics

1978 ◽  
Vol 36 (1) ◽  
pp. 268-269
Author(s):  
A. Zangvil ◽  
L.J. Gauckler ◽  
G. Schneider ◽  
M. Rühle
Keyword(s):  
Phase Diagrams ◽  
Crystal Structures ◽  
Thin Foil ◽  
Limited Extent ◽  
Complex Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Lattice Resolution

The use of high temperature special ceramics which are usually complex materials based on oxides, nitrides, carbides and borides of silicon and aluminum, is critically dependent on their thermomechanical and other physical properties. The investigations of the phase diagrams, crystal structures and microstructural features are essential for better understanding of the macro-properties. Phase diagrams and crystal structures have been studied mainly by X-ray diffraction (XRD). Transmission electron microscopy (TEM) has contributed to this field to a very limited extent; it has been used more extensively in the study of microstructure, phase transformations and lattice defects. Often only TEM can give solutions to numerous problems in the above fields, since the various phases exist in extremely fine grains and subgrain structures; single crystals of appreciable size are often not available. Examples with some of our experimental results from two multicomponent systems are presented here. The standard ion thinning technique was used for the preparation of thin foil samples, which were then investigated with JEOL 200A and Siemens ELMISKOP 102 (for the lattice resolution work) electron microscopes.

Current Status of Solid-State X-Ray Systems

1985 ◽  
Vol 43 ◽  
pp. 158-161
Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis
Keyword(s):  
Solid State ◽  
Electric Fields ◽  
Spectral Lines ◽  
Current Status ◽  
Mobile Charge ◽  
Electron Hole ◽  
X Ray ◽  
Sensing Systems ◽  
Transmission Electron ◽  
Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

scholarly journals Modern Microscopy on the Light Side: TEM in the Trenches

1993 ◽  
Vol 1 (4) ◽  
pp. 6-10
Author(s):  
Stephen E. Rice
Keyword(s):  
Science Fiction ◽  
Great Promise ◽  
Electron Holography ◽  
Imaging Device ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Light Side ◽  
Convergent Beam ◽  
Made In

Great strides have been made in the last decade in high resolution transmission electron microscopes (TEMs) which can also provide elemental information via energy dispersive X-ray analysis (EDX) or energy loss spectroscopy (EELS), and proponents of various TEM techniques make bold claims. Convergent beam elecjron diffraction and microdifff action shine as techniques for defect structure analysis and means for solving crystal structures. The spectroscopies can now be used to map chemical state information at a level which until recently might be encountered in science fiction. As a pure imaging device, electron holography holds great promise for providing Ehe ultimate (would you believe 0.1Å?) imaging resolution. Although conventional TEMs will never approach this, it appears that we are learning more and more about less and less, until we will soon know everything there is to know about nothing.

Aberration-corrected HRTEM of the Incommensurate Misfit Layer Compound (PbS)1.14NbS2

2007 ◽  
Vol 1026 ◽  
Author(s):  
Magnus Garbrecht ◽  
Erdmann Spiecker ◽  
Wolfgang Jäger ◽  
Karsten Tillmann
Keyword(s):  
Spherical Aberration ◽  
Atomic Scale ◽  
Transition Metal Dichalcogenide ◽  
Layer Compound ◽  
X Ray ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Interesting Class ◽  
Electron Microscopes ◽  
Set Up

AbstractThe development of tunable spherical aberration (Cs) imaging correctors for medium-voltage transmission electron microscopes (TEM) offers new opportunities for atomic-scale in-vestigations of materials. A very interesting class of microstructures regarding a variety of dif-ferent physical properties are the transition metal dichalcogenide misfit layer compounds exhibit-ing a high density of incommensurate interfaces due to their stacked nature. In the present study, the benefits coming along with the set-up of negative CS imaging (NCSI) conditions (in TEM) are demonstrated by means of different examples regarding local inhomogeneities in (PbS)1.14NbS2 crystals that can not be dissected in such detail by averaging x-ray techniques.

Sol–gel synthesis, structural and electrical properties of Li2CoSiO4 cathode material

2014 ◽  
Vol 07 (06) ◽  
pp. 1440001 ◽  
Author(s):  
Michał Świętosławski ◽  
Marcin Molenda ◽  
Piotr Natkański ◽  
Piotr Kuśtrowski ◽  
Roman Dziembaj ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Sol Gel ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Structural And Electrical Properties ◽  
Potential Alternative ◽  
Sol Gel Synthesis ◽  
First Time

Polyanionic cathode materials for lithium-ion batteries start to be considered as potential alternative for layered oxide materials. Among them, Li 2 CoSiO 4, characterized by outstanding capacity and working voltage, seems to be an interesting substitute for LiFePO 4 and related systems. In this work, structural and electrical investigations of Li 2 CoSiO 4 obtained by sol–gel synthesis were presented. Thermal decomposition of gel precursor was studied using EGA (FTIR)-TGA method. Chemical composition of the obtained material was confirmed using X-ray diffraction and energy-dispersive X-ray spectroscopy. The morphology of β- Li 2 CoSiO 4 was studied using transmission electron microscopy. High temperature electrical conductivity of Li 2 CoSiO 4 was measured for the first time. Activation energies of the electrical conductivity of two Li 2 CoSiO 4 polymorphs (β and γ) were determined. The room temperature electrical conductivity of those materials was estimated as well.

Quantification in Elemental DIstributions of Light Atoms by EEL Image Analysis in Biological Sections

1982 ◽  
Vol 40 ◽  
pp. 420-423
Author(s):  
F. P. Ottensmeyer
Keyword(s):  
Elemental Content ◽  
Single Element ◽  
X Ray ◽  
Transmission Electron ◽  
Spectral Evaluation ◽  
Scanning Transmission ◽  
Spectrum Characteristic ◽  
Electron Microscopes ◽  
Electron Energy Loss ◽  
Magnetic Electron

Microanalysis by electron energy loss spectroscopy has gained momentum in the last few years with the utilization of more and more magnetic electron spectrometers coupled to dedicated or hybrid scanning transmission electron microscopes. Two approaches to analysis are the spectral evaluation of a single spot and the mapping of a single element over the entire image. In the first method, as in x-ray microanalysis, a finely focused electron beam is placed on a small area of the specimen. The impinging electrons traversing this spot subsequently provide a spectrum characteristic of the elemental content of the area.

Energy-dispersive x-ray detectors for analytical electron microscopy

1991 ◽  
Vol 49 ◽  
pp. 986-987
Author(s):  
L. E. Thomas
Keyword(s):  
Collection Efficiency ◽  
Analytical Electron Microscopy ◽  
Energy Dispersive ◽  
Detector Performance ◽  
X Ray ◽  
Performance Improvements ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Scanning Transmission ◽  
Electron Microscopes

Continuing evolution of energy-dispersive x-ray spectrometer (EDS) systems has greatly advanced x-ray detector performance in analytical electron microscopes. The latest detectors offer improved energy resolution, count rate performance, geometrical collection efficiency, durability, and efficiency for light and heavy elements. Innovative detector designs for transmission and scanning transmission electron microscopes (TEM/STEMs) include such features as liquid-nitrogen-free operation, in situ de-icing of the detector crystal, user cleanable windows, demountable windows, ultrahigh vacuum compatibility (including adaptations to allow microscope bakeouts without removing the detector), beam damage protection, and microscope interfaces with optimized collection geometries. Divergent design philosophies have produced a variety of systems with specialized features, and users may face hard choices in selecting the best detector for the job. The aim of this paper is to review the current state of EDS detector development and the importance of the performance improvements to TEM/STEM users.

scholarly journals New capabilities for `colouring in' the chemistry of crystal defects atom-by-atom

2014 ◽  
Vol 70 (6) ◽  
pp. 521-523
Author(s):  
Sarah J. Haigh
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Crystal Defects ◽  
Energy Dispersive ◽  
Acta Cryst ◽  
X Ray ◽  
Elemental Imaging ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Microscopes

The latest generation of scanning transmission electron microscopes equipped with high-efficiency energy-dispersive X-ray detectors are breaking new ground with respect to high-resolution elemental imaging of materials. In this issue, Paulauskaset al.[Acta Cryst.(2014), A70, 524–531] demonstrate impressive results when applying this technique to improve understanding of CdTe dislocation structures.

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