Theory of the near K-edge structure in electron energy loss spectroscopy

2005 ◽  
Vol 143 (2-3) ◽  
pp. 51-64 ◽  
Author(s):  
A.T. Paxton
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Edge Structure ◽  
Electron Energy Loss

scholarly journals Vibrational signature of the graphene nanoribbon edge structure from high-resolution electron energy-loss spectroscopy

Nanoscale ◽  
2020 ◽  
Vol 12 (38) ◽  
pp. 19681-19688
Author(s):  
Nicola Cavani ◽  
Marzio De Corato ◽  
Alice Ruini ◽  
Deborah Prezzi ◽  
Elisa Molinari ◽  
...  
Keyword(s):  
High Resolution ◽  
Energy Loss ◽  
Electron Energy ◽  
Theoretical Investigation ◽  
Electron Energy Loss Spectroscopy ◽  
Graphene Nanoribbons ◽  
Graphene Nanoribbon ◽  
Edge Structure ◽  
Resolution Electron ◽  
Electron Energy Loss

A combined experimental and theoretical investigation of the vibrational signatures of on-surface synthesized graphene nanoribbons demonstrates the potentiality of HREELS in disclosing the details of their edge structure.

Evidence from EELS of Oxygen in the Nucleation Layer of a MBE grown III-N HEMT

1999 ◽  
Vol 595 ◽  
Author(s):  
Tyler J. Eustis ◽  
John Silcox ◽  
Michael J. Murphy ◽  
William J. Schaff
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Dark Field ◽  
Nitrogen Plasma ◽  
Diffuse Interface ◽  
Nucleation Layer ◽  
Edge Structure ◽  
Cornell University ◽  
Electron Energy Loss

AbstractThe presence of oxygen throughout the nominally AlN nucleation layer of a RF assisted MBE grown III-N HEMT was revealed upon examination by Electron Energy Loss Spectroscopy (EELS) in a Scanning Transmission Electron Microscope (STEM). The nucleation layer generates the correct polarity (gallium face) required for producing a piezoelectric induced high mobility two dimensional electron gas at the AlGaN/GaN heterojunction. Only AlN or AlGaN nucleation layers have provided gallium face polarity in RF assisted MBE grown III-N's on sapphire. The sample was grown at Cornell University in a Varian GenII MBE using an EPI Uni-Bulb nitrogen plasma source. The nucleation layer was examined in the Cornell University STEM using Annular Dark Field (ADF) imaging and Parallel Electron Energy Loss Spectroscopy (PEELS). Bright Field TEM reveals a relatively crystallographically sharp interface, while the PEELS reveal a chemically diffuse interface. PEELS of the nitrogen and oxygen K-edges at approximately 5-Angstrom steps across the GaN/AlN/sapphire interfaces reveals the presence of oxygen in the AlN nucleation layer. The gradient suggests that the oxygen has diffused into the nucleation region from the sapphire substrate forming this oxygen containing AlN layer. Based on energy loss near edge structure (ELNES), oxygen is in octahedral interstitial sites in the AlN and Al is both tetrahedrally and octahedrally coordinated in the oxygen rich region of the AlN.

Electron Energy Loss Spectroscopy Characterisation of the Sp2 Bonding Fraction Within Carbon Thin Films.

1999 ◽  
Vol 5 (S2) ◽  
pp. 632-633
Author(s):  
A.J. Papworth ◽  
C.J. Kiely ◽  
S.R.P. Silva ◽  
G.A.J. Amaratunga
Keyword(s):  
Thin Films ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Carbon Film ◽  
Edge Structure ◽  
Direct Technique ◽  
Peak Areas ◽  
Carbon Thin Films ◽  
Electron Energy Loss

Electron energy loss spectroscopy is the only direct technique that can semi-quantitatively determine the nature of the bonding in carbon thin films. To quantify the sp2/sp3 bonding fraction, the spectrum taken from the film must be compared to that of a suitable known standard. The bonding fraction can be analysed by studying the K ionisation edge in the electron energy loss spectrum. A method for quantifying the sp2 bonding fraction in an amorphous carbon film has been described by Berger et al (1988), where the area of peak of the film is compared with that of graphite. The principle of quantifying the edge structure is to obtain a ratio of the two peak areas using the following formula, (1), where fπis the ratio between the two π* peaks, Iπ. is the integral of the transition, and ΔE is the integrated counts for the normalising energy window. The superscripts s and u denote the standard and unknown spectra respectively.

Understanding Li-K edge structure and interband transitions in LixCoO2by electron energy-loss spectroscopy

2014 ◽  
Vol 104 (11) ◽  
pp. 114105 ◽  
Author(s):  
Jun Kikkawa ◽  
Shohei Terada ◽  
Akira Gunji ◽  
Mitsutaka Haruta ◽  
Takuro Nagai ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Interband Transitions ◽  
Edge Structure ◽  
Electron Energy Loss

Calculation of Electron Energy Loss Near Edge Structure by the Layered Kkr Method

1997 ◽  
Vol 3 (S2) ◽  
pp. 959-960
Author(s):  
P. Rez ◽  
J.M. Maclaren
Keyword(s):  
Theoretical Model ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Excited Atom ◽  
Atomic Scale ◽  
Spectral Features ◽  
Edge Structure ◽  
Electron Energy Loss ◽  
Selection Of

The analysis of near edge structure on inner shell ionisation edges in electron energy loss spectroscopy (EELS) can lead to new insights on the nature of bonding on an atomic scale. To fully understand the origins of spectral features it is necessary to calculate the near edge structure from a suitable theoretical model . Many of the previously published theories are based on multiple scattering of the ejected electron in a cluster of atoms surrounding the site of the excitation. The techniques used for the selection of scattering paths account for most of the differences between the various theories. In the XANES method the atoms in the vicinity of the excited atom are assigned to coordination shells and a separation is made between scattering within a given shell (intrashell) and scattering between shells (intershell). The FEFF method selects paths up to a given maximum length according to the number of scatterings and estimated amplitude.

Energy loss near‐edge structure for materials containing light elements by reflection electron energy loss spectroscopy

1995 ◽  
Vol 66 (1) ◽  
pp. 25-27 ◽  
Author(s):  
Toshinori Hayashi ◽  
Kiyoaki Araki ◽  
Shuji Takatoh ◽  
Toru Enokijima ◽  
Tetsurou Yikegaki ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Light Elements ◽  
Edge Structure ◽  
Electron Energy Loss

Imaging, Core-Loss, and Low-Loss Electron-Energy-Loss Spectroscopy Mapping in Aberration-Corrected STEM

2010 ◽  
Vol 16 (4) ◽  
pp. 416-424 ◽  
Author(s):  
Sorin Lazar ◽  
Yang Shao ◽  
Lina Gunawan ◽  
Riad Nechache ◽  
Alain Pignolet ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Core Loss ◽  
Unit Cell ◽  
Low Loss ◽  
Bright Field ◽  
Edge Structure ◽  
Electron Energy Loss ◽  
Aberration Corrected

AbstractHigh-angle annular dark-field and annular bright-field imaging experiments were carried out on an aberration-corrected transmission electron microscope. These techniques have been demonstrated on thin films of complex oxides Ba3.25La0.75Ti3O12 and on LaB6. The results show good agreement between theory and experiments, and for the case of LaB6 they demonstrate the detection of contrast from the B atoms in the annular bright-field images. Elemental mapping with electron-energy-loss spectroscopy has been used to deduce the distribution of Cr and Fe in a thin film of the complex oxide Bi2(Fe1/2Cr3/2)O6 at the unit cell level and the changes in the near-edge structure within the inequivalent regions in the crystalline unit cell. Energy-filtered images in the low-loss region of the energy-loss spectrum show contrast and resolution consistent with the modulation of the signals from elastic scattering. High-resolution contrast, mediated by phonon scattering, is observed for interband transitions. The limitations in terms of detection and signal are discussed.

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