EFTEM

Energy-filtered transmission electron microscopy (EFTEM) is a family of imaging techniques to enhance, map and quantify elements and chemicals in an image.

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Overview: 

Energy-filtered transmission electron microscopy (EFTEM) is a family of imaging techniques that utilize properties of the energy loss spectrum to increase contrast, remove the effects of chromatic aberration and create unique contrast effects in the image. Key applications include:

  • Contrast enhancement – Improves contrast in images and diffraction patterns when it removes inelastically scattered electrons that produce background fog
    • Including zero-loss filtering, most probable loss imaging, contrast tuning, and pre-carbon imaging
  • Mapping – Creates elemental/chemical maps at nanometer resolution by forming images with inelastically scattered electrons
    • Including 2- and 3-window elemental mapping/jump-ratio imaging and chemical mapping – provides fine structure imaging
  • Analytical – Records and quantifies electron energy loss spectra (and maps) to provide chemical analysis of TEM samples

The principle behind EFTEM is based on the illumination of a very thin specimen with a beam of high energy electrons. When the majority electrons pass unhindered through the specimen, some will interact with the specimen and result in elastic or inelastic scattering. Inelastic scattering results in both a loss of energy and a change in momentum, which in the case of inner shell ionization is characteristic of the element in the sample.

For more information on the EELS family of techniques, please visit EELS.info, an educational site.

Resources:

 

Applications

EELS.info

Atomic level EELS mapping using high energy edges in DualEELS™ mode
High-speed EELS composition analysis, in DualEELS mode, of metal alloy ohmic contacts for the fabrication of III-V MOSFET devices
EELS: A tool for investigating biological materials
Fast simultaneous acquisition of low- and core-loss regions in the EELS spectrum from catalyst particles containing the heavy metals Au and Pd using the GIF Quantum® system
Fast STEM spectrum imaging using simultaneous EELS and EDS in Gatan Microscopy Suite® software
Review of recent advances in spectrum imaging and its extension to reciprocal space
The use of MLLS fitting approach to resolve overlapping edges in the EELS spectrum at the atomic level

Posters

Fast STEM EELS spectrum imaging analysis of Pd-Au based catalysts
The high efficiency of the latest generation EELS spectrometers allow highly detailed EELS spectra from heavy elements to be acquired in a matter of milliseconds resulting in composition maps with outstanding information content.

A quantitative investigation of biological materials using EELS
EELS has proved to be a valuable tool to obtain compositional information from biological samples. In addition to the composition, EELS also gives insight into the chemistry unveiling the nature of the chemical bonds and different oxidation states.

High-speed composition analysis of high-z metal alloys in DualEELS mode
Demonstrating that high-speed atomic EELS composition maps with high contrast and high signal-to-noise ratio can be acquired routinely from high-energy edges.

Fast atomic level EELS mapping analysis using high-energy edges in DualEELS mode
Demonstrating that atomic EELS mapping using high-energy edges is very effective. The high signal-to-background ratio of high-energy edges leads to simplified data extraction.

Atomic resolved EELS analysis across interfaces in III-V MOSFET high-k dielectric gate stacks
Demonstrating that EELS SI can reveal the elemental distribution at the gate of high-k MOSFET devices at atomic column level.

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