Analytical Electron Microscopy of Precipitates in Ion-Implanted Mgal2O4 Spinel

1994 ◽  
Vol 373 ◽  
Author(s):  
N. D. Evans ◽  
S. J. Zinkle ◽  
J. Bentley
Keyword(s):  
Electron Microscopy ◽  
Energy Loss ◽  
Volume Fraction ◽  
Analytical Electron Microscopy ◽  
Metallic Aluminum ◽  
X Ray ◽  
Electron Energy Loss Spectrometry ◽  
Analytical Electron ◽  
Electron Energy Loss ◽  
Ion Implanted

AbstractAnalytical electron microscopy (AEM) has been used to investigate precipitates in MgAl2O4 spinel implantated with Al+, Mg+, or Fe2+ ions. Experiments combining diffraction, energy dispersive X-ray spectrometry (EDS), electron energy-loss spectrometry (EELS), and energy-filtered imaging were employed to identify and characterize precipitates observed in the implanted ion region. Diffraction studies suggested these are metallic aluminum colloids, although EELS and energy-filtered images revealed this to be so only for the Al+ and Mg+ implantations, but not for Fe2+ ion implantations. Multiple-least-squares (MLS) fitting of EELS plasmon spectra was employed to quantify the volume fraction of metallic aluminum in the implanted ion region. Energy-filtered plasmon images of the implanted ion region clearly show the colloid distribution in the Al+ and Mg+ implanted spinel. Energy-filtered images from the Fe2+ ion implanted spinel indicate that the features visible in diffraction contrast cannot be associated with either metallic aluminum or iron-rich precipitates.

Detection limits for Analytical Electron Microscopy with Electron Energy Loss Spectrometry and energy-dispersive x-ray spectrometry

1993 ◽  
Vol 51 ◽  
pp. 594-595
Author(s):  
Dale E. Newbury ◽  
Richard D. Leapman
Keyword(s):  
Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Cross Section ◽  
Analytical Electron Microscopy ◽  
Energy Dispersive ◽  
X Ray ◽  
Electron Energy Loss Spectrometry ◽  
Analytical Electron ◽  
Electron Energy Loss

The measurement of trace level constituents, arbitrarily defined for this study as concentration levels below 1 atom percent, has always been considered problematic for analytical electron microscopy (AEM) with energy dispersive x-ray spectrometry (EDS) and electron energy loss spectrometry (EELS). In a landmark study of various microanalysis techniques, Wittry evaluated the influence of various instrumental factors (source brightness, detection efficiency, accumulation time) and physical factors (cross section, peak-to-background) upon detection limits. Although the ionization cross section, fluorescence yield, and collection efficiency favor EELS over EDS, the peak-to-background ratio of EELS spectra is much lower than that of EDS spectra, leading Wittry to suggest that the limit of detection should be 0.1 percent for EDS and 1 percent for EELS for practical measurement conditions. Recent developments in parallel detection EELS (PEELS) indicate that a re-evaluation of the situation for trace constituent determination is needed for those elements characterized by "white line" resonance structures at the ionization edge.

The Use of ELNES for Microanalysis

1999 ◽  
Vol 5 (S2) ◽  
pp. 664-665
Author(s):  
A.J. Craven ◽  
M. MacKenzie
Keyword(s):  
Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Analytical Electron Microscopy ◽  
Local Environment ◽  
Edge Structure ◽  
Similar Shape ◽  
Analytical Electron ◽  
Electron Energy Loss ◽  
Combining Information

The performance of many materials systems depends on our ability to control the distribution of atoms on a nanometre or sub-nanometre scale within those systems. This is as true for steels as it is for semiconductors. A key requirement for improving their performance is the ability to determine the distribution of the elements resulting from processing the material under a given set of conditions. Analytical electron microscopy (AEM) provides a range of powerful techniques with which to investigate this distribution. By combining information from different techniques, many of the ambiguities of interpretation of the data from an individual technique can be eliminated. The electron energy loss near edge structure (ELNES) present on an ionisation edge in the electron energy loss spectrum reflects the local structural and chemical environments in which the particular atomic species occurs. Thus it is a useful contribution to the information available. Since a similar local environment frequently results in a similar shape, ELNES is useful as a “fingerprint”.

NiO Test Specimens for Analytical Electron Microscopy: Round-Robin Results

1995 ◽  
Vol 1 (4) ◽  
pp. 143-149 ◽  
Author(s):  
J.C. Bennett ◽  
R.F. Egerton
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Test Specimen ◽  
Analytical Electron Microscopy ◽  
X Rays ◽  
Elemental Ratios ◽  
X Ray ◽  
Analytical Electron ◽  
Electron Energy Loss ◽  
Nio Films

Improvements in instrumentation for energy-dispersive X-ray microanalysis (EDX) and electron energy-loss spectroscopy (EELS) have underlined the need for suitable standards for measuring performance. We report the results from several laboratories that were supplied with a test specimen consisting of a thin film of nickel oxide supported on a molybdenum grid. The Ni-Kα/Mo-Kα count ratio was used as an indication of number of stray electrons and/or X-rays in the TEM column; the Ni-Kα peak/background ratio provided a measure of the total background in the EDX spectrum, including bremsstrahlung contributions and the effect of detector electronics. By providing values typical of current instrumentation, the results illustrate how the test specimen can be used to evaluate TEM/EDX systems prior to purchase, during installation, and (periodically) during operation. The NiO films were also used to test EELS acquisition and quantification procedures: measured Ni/O elemental ratios were all within 10% of stoichiometry.

scholarly journals Analytical electron microscopy at the atomic level with parallel electron energy loss spectroscopy

1990 ◽  
Vol 1 (5-6) ◽  
pp. 443-454 ◽  
Author(s):  
Danièle Bouchet ◽  
Christian Colliex ◽  
Parmjit Flora ◽  
Ondrej Krivanek ◽  
Claudie Mory ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Analytical Electron Microscopy ◽  
Atomic Level ◽  
Analytical Electron ◽  
Electron Energy Loss

Magnetic spectrometers with corrected second-order aberrations

1978 ◽  
Vol 36 (1) ◽  
pp. 46-47
Author(s):  
N.W. Parker ◽  
M. Utlaut ◽  
M. Isaacson
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Energy Loss ◽  
Focal Plane ◽  
Energy Analysis ◽  
Analytical Electron Microscopy ◽  
Second Order ◽  
Uniform Field ◽  
Analytical Electron ◽  
Electron Energy Loss

Recent years have seen tremendous advances in analytical electron microscopy and increased interest in electron energy loss spectroscopy has been especially prominent. Due to these developments there have been many discussions in the literature of the use of magnetic spectrometers in energy analysis. The aberrations of magnetic prisms have also received numerous treatments [1-4] although not specifically emphasizing energy analysis in the electron microscope. The importance of the objective and post-specimen lenses on the effective spectrometer resolution, however, has been discussed in recent papers by Crewe [5,6]. To our knowledge, the correction of those aberrations of importance in an electron microscope spectrometer have not been adequately delineated. Recent work of H. Shuman, et al. [7] has demonstrated whole sets of uniform field magnetic prisms with curved pole faces which simultaneously eliminate the main second-order aberrations affecting the energy resolution in addition to making the focal plane perpendicular to the central ray (useful for parallel recording of spectra).

Analytical Electron Microscopy of a Polymer Blend

1985 ◽  
Vol 43 ◽  
pp. 80-81
Author(s):  
T. Haddock ◽  
S.J. Krause ◽  
S. Kumar ◽  
W.W. Adams
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Polymer Blend ◽  
Analytical Electron Microscopy ◽  
High Strength ◽  
X Ray ◽  
Analytical Electron ◽  
Flexible Coil ◽  
Electron Energy Loss ◽  
Beam Damage

A polymer blend which is composed of poly-p-phenylene benzobisthiazole (PBT) and poly-2,5(6)benzimidazole (ABPBI) has been processed into both a phase-separated material and a “molecular composite”. In the molecular composite, the PBT and ABPBI components are dispersed at a scale finer than 3 nm. This results in high mechanical properties as the rod-like, high strength PBT reinforces the flexible-coil ABPBI matrix. In the phase- separated blend, micron-sized aggregates form within a more ductile matrix. This study qualitatively examines the structure and composition of the phase- separated 20% PBT / 80% ABPBI blend using the analytical electron microscopy (AEM) techniques of energy dispersive x-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS), and microdiffraction. Beam damage of the components is also considered.

Structural and Chemical Microanalysis of Oxygen-Bearing Precipitates in Silicon

1982 ◽  
Vol 14 ◽  
Author(s):  
R.W. Carpenter ◽  
I. Chan ◽  
H.L. Tsai ◽  
C. Varker ◽  
L.J. Demer
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Low Density ◽  
X Ray ◽  
Analytical Electron ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra ◽  
Metallic Impurities ◽  
Stage Heat Treatment ◽  
Plate Type

ABSTRACTPrecipitation in CZ-silicon during post-growth two-stage heat treatment has been examined using the methods of high resolution analytical electron microscopy. Electron transparent specimens prepared from these specimens, exhibited a low density of plate type precipitates on {100} planes. Microdiffraction experiments showed the precipitates to be consistently non-crystalline. Electron energy loss spectra showed that the precipitates contained oxygen, but carbon was not detected. It was found that carbon artifact absorption edges could be induced in spectra by specimen contamination in the microscope. The use of a low temperature stage eliminated this problem. Complementary characteristic x-ray microanalysis showed that metallic impurities had not segregated to these precipitates in this particular case, although this has been observed elsewhere.

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