Observation of interband transitions in polarized electron energy loss spectra of Gd(0001)

1985 ◽  
Vol 58 (4) ◽  
pp. 261-265 ◽  
Author(s):  
D. Weller ◽  
S. F. Alvarado
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Interband Transitions ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra

Observations of Direct Non-Vertical Interband Transitions in Al and Si by Electron Energy-Loss Spectroscopy.

1976 ◽  
Vol 34 ◽  
pp. 518-519
Author(s):  
C. H. Chen ◽  
J. Silcox
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Interband Transitions ◽  
Energy Bands ◽  
Linear Dispersion ◽  
Plasmon Peak ◽  
Bulk Plasmon ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra ◽  
Second Peak

Electron energy-loss spectra (at 75keV) of single crystal aluminum and silicon foils of [001] orientation were obtained by using an electron microscope (Hitachi HU-11A)-electron spectrometer (Wien filter) system. The operation of this apparatus has been described previously. In the present experiment, the microscope was operated in the selected-areadiffraction mode and the energy-loss spectra were recorded on photographic plates and subsequently obtained data by microdensitometry.Figure 1 shows the loss spectrum in aluminum with momentum transfer q in the <100> direction. In addition to the usual bulk plasmons at 15eV and surface plasmons at 6.7eV, two dispersive peaks below the bulk plasmon peak are also observed. The first peak which is relatively sharp starts linearly from 1.5eV at q∼0 and levels off around 9eV at the zone boundary (q = 1. 55 Å-1) . This peak is due to the excitation of direct non-vertical interband transitions along the X-W-X direction of energy bands in Al. The second peak, broad and diffuse with energy higher than the first one, has approximately linear dispersion which extends beyond 12eV and shows no sign of leveling off at large q.

Parallel Detection of Electron Energy Loss Spectra in Direct Mode

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.

Electron energy loss spectra of a Pd(110) clean surface

1986 ◽  
Vol 58 (1) ◽  
pp. 75-77 ◽  
Author(s):  
M. Nishijima ◽  
M. Jo ◽  
Y. Kuwahara ◽  
M. Onchi
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Clean Surface ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra
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