Deconvolution of core loss electron energy loss spectra

1985 ◽

Vol 398 (1815) ◽

pp. 395-404 ◽

Cited By ~ 33

Keyword(s):

Fine Structure ◽

Energy Loss ◽

Electron Energy ◽

Core Loss ◽

Single Scattering ◽

Electron Interaction ◽

Edge Structure ◽

Fourier Deconvolution ◽

Electron Energy Loss ◽

Electron Energy Loss Spectra

Electron energy-loss spectroscopy (e. e. l. s.) performed with an electron microscope can be used to obtain plasmon spectra, near-edge fine structure and extended electron energy-loss fine structure (ex. e. l. f. s.), as well as to do chemical analysis on truly microscopic samples. However, the very strength of the electron–electron interaction gives rise to significant and sometimes predominant plural scattering effects. To obtain consistent and reliable estimates of the single scattering distributions these effects must be accounted for. In this paper, two Fourier-transform deconvolution methods of removing plural scattering from electron energy-loss spectra and their implementation on a microcomputer, are discussed. Their relative advantages and limitations are considered together with examples of artefacts that may arise in both plasmon and core-loss spectra. As a result of deconvolution the sensitivity and accuracy of core-elemental analysis is enhanced but, more importantly, it is possible to obtain reproducible near-edge structure and plasmon spectra from relatively thick samples that would otherwise not be suitable for investigation by means of e. e. l. s.

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Quantitative Electron Energy Loss Mapping

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118898 ◽

1985 ◽

Vol 43 ◽

pp. 404-405

Author(s):

R.D. Leapman ◽

C.R. Swyt

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Electron Energy Loss Spectroscopy ◽

Elemental Concentration ◽

Core Loss ◽

Elemental Distribution ◽

Electron Energy Loss

The intensity of a characteristic electron energy loss spectroscopy (EELS) image does not, in general, directly reflect the elemental concentration. In fact, the raw core loss image can give a misleading impression of the elemental distribution. This is because the measured core edge signal depends on the amount of plural scattering which can vary significantly from region to region in a sample. Here, we show how the method for quantifying spectra due to Egerton et al. can be extended to maps.

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Parallel Detection of Electron Energy Loss Spectra in Direct Mode

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134004 ◽

1990 ◽

Vol 48 (2) ◽

pp. 82-83

Author(s):

Eckhard Quandt ◽

Stephan laBarré ◽

Andreas Hartmann ◽

Heinz Niedrig

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Energy Resolution ◽

Large Angle ◽

Maximum Energy ◽

Semiconductor Detectors ◽

Parallel Detection ◽

Photodiode Arrays ◽

Electron Energy Loss ◽

Electron Energy Loss Spectra

Due to the development of semiconductor detectors with high spatial resolution -- e.g. charge coupled devices (CCDs) or photodiode arrays (PDAs) -- the parallel detection of electron energy loss spectra (EELS) has become an important alternative to serial registration. Using parallel detection for recording of energy spectroscopic large angle convergent beam patterns (LACBPs) special selected scattering vectors and small detection apertures lead to very low intensities. Therefore the very sensitive direct irradiation of a cooled linear PDA instead of the common combination of scintillator, fibre optic, and semiconductor has been investigated. In order to obtain a sufficient energy resolution the spectra are optionally magnified by a quadrupole-lens system.The detector used is a Hamamatsu S2304-512Q linear PDA with 512 diodes and removed quartz-glas window. The sensor size is 13 μm ∗ 2.5 mm with an element spacing of 25 μm. Along with the dispersion of 3.5 μm/eV at 40 keV the maximum energy resolution is limited to about 7 eV, so that a magnification system should be attached for experiments requiring a better resolution.

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In Situ Analysis of Surface Contaminant Desorption during Low-Temperature Silicon Substrate Cleaning using Reflection Electron Energy Loss Spectrometry

MRS Proceedings ◽

10.1557/proc-259-449 ◽

1992 ◽

Vol 259 ◽

Cited By ~ 1

Author(s):

Selmer S. Wong ◽

Shouleh Nikzad ◽

Channing C. Ahn ◽

Aimee L. Smith ◽

Harry A. Atwater

Keyword(s):

Low Temperature ◽

Energy Loss ◽

Electron Energy ◽

Core Loss ◽

Temperature Dependent ◽

Electron Energy Loss Spectrometry ◽

Analysis Technique ◽

Chemical Analysis Technique ◽

Electron Energy Loss

ABSTRACTWe have employed reflection electron energy loss spectrometry (REELS), a surface chemical analysis technique, in order to analyze contaminant coverages at the submonolayer level during low-temperature in situ cleaning of hydrogen-terminated Si(100). The chemical composition of the surface was analyzed by measurements of the C K, O K and Si L2,3 core loss intensities at various stages of the cleaning. These results were quantified using SiC(100) and SiO2 as reference standards for C and O coverage. Room temperature REELS core loss intensity analysis after sample insertion reveals carbon at fractional monolayer coverage. We have established the REELS detection limit for carbon coverage to be 5±2% of a monolayer. A study of temperature-dependent hydrocarbon desorption from hydrogen-terminated Si(100) reveals the absence of carbon on the surface at temperatures greater than 200°C. This indicates the feasibility of epitaxial growth following an in situ low-temperature cleaning and also indicates the power of REELS as an in situ technique for assessment of surface cleanliness.

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