Ab initio calculation of band structure, x‐ray emission, quantum yield, and electron‐energy‐loss spectra of hexagonal boron nitride

1993 ◽  
Vol 73 (11) ◽  
pp. 7422-7426 ◽  
Author(s):  
H. Ma ◽  
S. H. Lin ◽  
R. W. Carpenter ◽  
P. Rice ◽  
O. F. Sankey
Keyword(s):  
Quantum Yield ◽  
Boron Nitride ◽  
Band Structure ◽  
Energy Loss ◽  
Ab Initio Calculation ◽  
Hexagonal Boron Nitride ◽  
X Ray ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra ◽  
Emission Quantum Yield

The Combined Effect of Channelling and Blocking in Electron Energy Loss Spectroscopy

1981 ◽  
Vol 39 ◽  
pp. 190-191
Author(s):  
J. Taftø ◽  
O. L. Krivanek
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Bragg Reflection ◽  
Incident Beam ◽  
Orientation Dependence ◽  
Planar Case ◽  
X Ray ◽  
Crystal Unit Cell ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra

Bragg reflection of electrons gives rise to a modulation of the wavefield over the crystal unit cell. Depending on the incident beam direction the electrons may be concentrated at one or another type of atoms or between them. Localized ionization processes will therefore show an orientation dependence, and this will affect the X-ray emission intensities as well as electron energy loss spectra. The energy loss case gives more possibilities for experimental arrangements than the X-ray emission case, in that the direction of not only the incident electron beam, but also that of the exit beam to be analyzed may be selected.Natural MgAl2O4 spinel was studied. The crystals were ground in a mortar and thin areas were analyzed with a Gatan 607 spectrometer attached to a Philips 400T electron microscope operating at lOOkV. The experiments were done for the (400)-planar case where the main atomic planes contain Al2O4. The Mg-atoms are midway between the A12O4 and may be considered as interstitials in this planar case.

Element analysis with the imaging electron energy loss spectrometer of the zeiss EM 902

1986 ◽  
Vol 44 ◽  
pp. 600-601
Author(s):  
J. Bihr ◽  
A. Rilk ◽  
W.I. Miller
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Spectroscopic Imaging ◽  
Element Analysis ◽  
X Ray ◽  
Electron Energy Loss Spectrometer ◽  
Elemental Maps ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra ◽  
Loss Range

An imaging electron energy loss spectrometer can be used to produce elemental maps with highest spatial resolution by Electron Spectroscopic Imaging (ESI). Simultaneously, electron energy loss spectra (EELS) can also be recorded. It is therefore simple to combine morphological examinations with the analytical method of electron energy loss spetroscopy (Figs. 2, 3)The electron energy loss spectrometer of the EM 902, used in combination with a suitable electron detector (Fig. 1), provides the possibility of recording electron energy loss spectra over an energy loss range from 0 to 2000 eV. In this way, all elements of the periodic system can be detected via their K, L, M, N or O absorption edges (Fig. 5). Unlike X-ray microanalysis, this technique is especially suitable for detecting light and medium-heavy elements which are of special significance in biological and medical research.

Electron energy loss spectra and X-ray photoelectron spectra of Ca2V2O7

1983 ◽  
Vol 28 (2) ◽  
pp. 123-133 ◽  
Author(s):  
I.M. Curelaru ◽  
E. Suonien ◽  
E. Minni ◽  
K.-G. Strid ◽  
T. Rönnhult
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra

Optical Gap Measurements on Individual Boron Nitride Nanotubes by Electron Energy Loss Spectroscopy

2008 ◽  
Vol 14 (3) ◽  
pp. 274-282 ◽  
Author(s):  
Raul Arenal ◽  
Odile Stéphan ◽  
Mathieu Kociak ◽  
Dario Taverna ◽  
Annick Loiseau ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Hexagonal Boron Nitride ◽  
Boron Nitride Nanotubes ◽  
Electromagnetic Response ◽  
Optical Gap ◽  
Spatially Resolved ◽  
Electron Energy Loss

AbstractElectromagnetic response of individual boron nitride nanotubes (BNNTs) has been studied by spatially resolved electron energy loss spectroscopy (EELS). We demonstrate how dedicated EELS methods using subnanometer electron probes permit the analysis of local dielectric properties of a material on a nanometer scale. The continuum dielectric model has been used to analyze the low-loss EEL spectra recorded from these tubes. Using this model, we demonstrate the weak influence of the out-of-plane contribution to the dielectric response of BNNTs. The optical gap, which can be deduced from the measurements, is found to be equal to 5.8 ± 0.2 eV, which is close to that of the hexagonal boron nitride. This value is found to be independent of the nanotubes configuration (diameter, helicity, number of walls, and interaction between the different walls).

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