Journal articles: 'Low loss plasmon electron energy loss spectrum'

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Longo, Paolo, Ray D. Twesten, and Jaco Olivier. "Probing the Chemical Structure in Diamond-Based Materials Using Combined Low-Loss and Core-Loss Electron Energy-Loss spectroscopy." Microscopy and Microanalysis 20, no. 3 (March 25, 2014): 779–83. http://dx.doi.org/10.1017/s1431927614000579.

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AbstractWe report the analysis of the changes in local carbon structure and chemistry caused by the self-implantation of carbon into diamond via electron energy-loss spectroscopy (EELS) plasmon energy shifts and core-edge fine structure fingerprinting. These two very different EELS energy and intensity ranges of the spectrum can be acquired under identical experimental conditions and nearly simultaneously using specially designed deflectors and energy offset devices known as “DualEELS.” In this way, it is possible to take full advantage of the unique and complementary information that is present in the low- and core-loss regions of the EELS spectrum. We find that self-implanted carbon under the implantation conditions used for the material investigated in this paper creates an amorphous region with significant sp2 content that varies across the interface.

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Bellido, Edson P., David Rossouw, and Gianluigi A. Botton. "Toward 10 meV Electron Energy-Loss Spectroscopy Resolution for Plasmonics." Microscopy and Microanalysis 20, no. 3 (April 1, 2014): 767–78. http://dx.doi.org/10.1017/s1431927614000609.

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AbstractEnergy resolution is one of the most important parameters in electron energy-loss spectroscopy. This is especially true for measurement of surface plasmon resonances, where high-energy resolution is crucial for resolving individual resonance peaks, in particular close to the zero-loss peak. In this work, we improve the energy resolution of electron energy-loss spectra of surface plasmon resonances, acquired with a monochromated beam in a scanning transmission electron microscope, by the use of the Richardson–Lucy deconvolution algorithm. We test the performance of the algorithm in a simulated spectrum and then apply it to experimental energy-loss spectra of a lithographically patterned silver nanorod. By reduction of the point spread function of the spectrum, we are able to identify low-energy surface plasmon peaks in spectra, more localized features, and higher contrast in surface plasmon energy-filtered maps. Thanks to the combination of a monochromated beam and the Richardson–Lucy algorithm, we improve the effective resolution down to 30 meV, and evidence of success up to 10 meV resolution for losses below 1 eV. We also propose, implement, and test two methods to limit the number of iterations in the algorithm. The first method is based on noise measurement and analysis, while in the second we monitor the change of slope in the deconvolved spectrum.

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Bell, David C. "Electron Scattering In Diamond as a Function of Thickness." Microscopy and Microanalysis 4, S2 (July 1998): 338–39. http://dx.doi.org/10.1017/s1431927600021814.

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BackgroundThe electron energy-loss spectrum of a single crystal diamond wedge has been examined, with particular reference to the excitation of plasmon oscillations in the bulk of a diamond crystal. The electron energy-loss spectrum has been previously studied [1], and in particular the ‘low-lo ss’ region of the spectrum shows a number of important features, Fig. 1. The main feature in the energy-loss spectrum is a peak at ∼ 33 eV which corresponds to a plasma resonance of valence electrons. Diamond has 4 valence electrons which yields a value of Ep = 31.0 eV. The upward shift in the resonance energy to 33 eV is caused by single-electron excitation at lower energy-loss values. An important feature is the “bump” at about 23 eV, which has been shown to be an interband transition [2].

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Luo, Suichu, John R. Dunlap, and David C. Joy. "Modulation electron energy loss spectroscopy and its application of quantitative analysis." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 454–55. http://dx.doi.org/10.1017/s0424820100148101.

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Electron energy loss spectroscopy (EELS) gives an inportant insight into the variety of excitations a sample may undergo when irradiated by an electron beam. The focus of this work was to simulate electronic excitations within the energy range from a few to several hundred eV. Our recently developed modulation scheme, combines both convolution and deconvolution techniques, to provide quantitative information about elementary inelastic scattering processes without knowledge of sample parameters such as thickness or optical constants.In the low energy loss region of the spectrum the primary excitation mechanisms include interband transitions, and surface and bulk plasmons. In general these individual excitation events overlap in the spectrum. A FFT convolution procedure was developed where the basic inelastic processes may be represented by the dielectric theory . The dielectric function ε is used to describe both single excitations and collective excitations, where Here ωp2=4πNe2/m is the bulk plasmon frequency, N is number of free electrons per unit volume, e and m are the charge and mass of the electron respectively and ω0 is a constant which is finite for a bound state but zero for a free electron.

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Wang, Z. L. "Energy-filtered high-resolution Electron Microscopy of nanostructured materials." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 176–77. http://dx.doi.org/10.1017/s0424820100137252.

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The interaction between an incident electron and the atoms in condensed matter results in various inelastic scattering processes. Thermal diffuse scattering or phonon scattering is the result of atomic vibrations in crystals. This process does not introduce any significant energy-loss (< 0.1 eV) but produces large momentum transfer. Valence-loss (or plasmon for metals and semiconductors) excitation, which characterizes the transitions of electrons from the valence band to the conduction band, involves an energyloss in the range of 1 -50 e V. Atomic inner-shell ionization is excited by the energy transfer of the incident electron, resulting in an ejected electron from the deep-core states. Continuous energy-loss spectra can also be generated by an electron which penetrates into the specimen and undergoes collisions with the atoms in it, resulting in Bremsstrahlung and leading to emission of x-rays with continuous energy. The electron Compton scattering refers to the collision of the incident electron with an electron belonging to the specimen. In an electron energy-loss spectrum (EELS), the zero-loss peak is composed of elastically and thermal diffusely scattered electrons. The low-loss region is dominated by valence-excitations.

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Reimer, L. "Energy-filtering Transmission Electron Microscopy in materials and life science." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 936–37. http://dx.doi.org/10.1017/s0424820100172413.

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Energy-filtering transmission electron microscopy can be realized by an imaging filter lens in thecolumn of a TEM, a post-column electron energy-loss spectrometer or a dedicated STEM. This offers new possibilities in analytical electron microscopy by combining the operation modes of electron-spectroscopic imaging (ESI), electron-spectroscopic diffraction (ESD) and the record of an electron energy-loss spectrum (EELS).ESI can be used in the zero-loss mode to remove all inelastically scattered electrons. Thicker amorphous and crystalline specimens can be observed without chromatic aberration and with a transmissionof 10−3 up to 80(110) and 150(200) μg/cm2 at 80(120) keV, respectively. This results in a condiserable increase of scattering, phase and Bragg contrast, especially for low Z material because the ratio of inelastic-to-elastic cross section increases as 20/Z with decreasing atomic number. In future energy-filtered high-resolution crystal-lattice images will offer us a better comparison with dynamical simulations. Plasmon loss filtering can be applied for a better separation of phases (e.g. precipitates in a matrix), which differ in their plasmon loss by about 1 eV. Owing to intersections of the energy loss spectra, different parts of a specimen can change their contrast when tuning the selected energy window. Structures containing non carbon atoms will beconsiderably increased in a bright field like contrast relative to the carboneous matrix just below the carbon K edge (structure—sensitive imaging).

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Mondio, G., F. Neri, G. Curró, S. Patané, and G. Compagnini. "The dielectric constant of TCNQ single crystals as deduced by reflection electron energy loss spectroscopy." Journal of Materials Research 8, no. 10 (October 1993): 2627–33. http://dx.doi.org/10.1557/jmr.1993.2627.

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The dielectric constant of tetracyanoquinodimethane (TCNQ) single crystals has been obtained by reflection electron energy loss spectroscopy (REELS) over the 0–60 eV energy range, using primary electron energies ranging from 0.5 to 1.5 keV at an incidence angle of about 40°. A self-consistent method is discussed concerning the evaluation of the surface and bulk contributions to the loss spectra. As a result, for the first time, the Im(−1/∊) function and the dielectric constant of TCNQ have been deduced in such a wide energy range. According to the results obtained by other authors, the low-energy loss spectral profile is characterized by two main structures ascribed to the π → π∗ dipole-allowed transitions located at about 3.5 and 6.5 eV while, at higher energy loss, the π + σ plasmon, centered at about 21.5 eV, dominates the spectrum. The differences among the spectra taken at different primary energies are interpreted as due only to surface effects, more evident in the low-energy-loss spectral region. The results are in good agreement with those obtained by recent transmission-mode (TEELS) experiments.

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UGARTE, Daniel. "STEM Study of Surface Plasmon Excitation in Small Spherical Particles." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 42–43. http://dx.doi.org/10.1017/s0424820100133801.

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Small particles exhibit chemical and physical behaviors substantially different from bulk materials. This is due to the fact that boundary conditions can induce specific constraints on the observed properties. As an example, energy loss experiments carried out in an analytical electron microscope, constitute a powerful technique to investigate the excitation of collective surface modes (plasmons), which are modified in a limited size medium. In this work a STEM VG HB501 has been used to study the low energy loss spectrum (1-40 eV) of silicon spherical particles [1], and the spatial localization of the different modes has been analyzed through digitally acquired energy filtered images. This material and its oxides have been extensively studied and are very well characterized, because of their applications in microelectronics. These particles are thus ideal objects to test the validity of theories developed up to now.Typical EELS spectra in the low loss region are shown in fig. 2 and energy filtered images for the main spectral features in fig. 3.

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Keast, V. J. "Ab initio calculations of plasmons and interband transitions in the low-loss electron energy-loss spectrum." Journal of Electron Spectroscopy and Related Phenomena 143, no. 2-3 (May 2005): 97–104. http://dx.doi.org/10.1016/j.elspec.2004.04.005.

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Wang, Z. L., and P. Rez. "Inner-shell energy loss spectroscopy under reflection-microscopy condition." Proceedings, annual meeting, Electron Microscopy Society of America 45 (August 1987): 120–21. http://dx.doi.org/10.1017/s0424820100125531.

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Electron energy loss spectroscopy(EELS) of the inner shells of atoms is now a well established technique for determination of specimen composition, especially for the light elements. In recent years there has been a revival interest in reflection electron microscopy(REM) as a method for examining surface morphology. It would be useful if the techniques of bulk microanalysis could also be applied in reflection mode. The first electron microscope reflection energy loss measurement were due to Krivanek et al. They successfully showed the enhancement of the surface plasmon in silicon but the Si L edge at 100eV could only be seen as a change in spectrum shape. This is a characteristic of multiple scattering and it is hardly surprising that it should be more important in REM. Multiple scattering in TEM limits energy loss to relatively thin regions, but even under conditions in which multiple scattering has eliminated a low energy edge (such as Si L) the edge of a deep inner shell with binding energy greater than 1 kV can still be clearly seen, though sometimes distorted in shape.

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Yajid, M. A. Mat, and G. Möbus. "Reactive Multilayers Examined by HRTEM and Plasmon EELS Chemical Mapping." Microscopy and Microanalysis 15, no. 1 (January 15, 2009): 54–61. http://dx.doi.org/10.1017/s1431927609090035.

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AbstractWe examine chemical mapping of reaction phases in a Cu-Al multilayer system using low-loss electron energy loss spectroscopy spectrum imaging and image spectroscopy techniques. The sensitivity of the plasmon peak position and shape to various crystal structures and phases is exploited using postprocessing of spectra into second derivative plasmon maps and line scans. Analytical transmission electron microscopy is complemented by studies of the orientation relationship of the multilayer system using high-resolution electron microscopy of interfaces and selected area diffraction. The techniques have been applied to the Cu-Al multilayer sample and sharply bound epitaxial phases are found, before and after heat treatment.

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Probst, Wolfgang, Erhard Zellmann, and Richard Bauer. "Energy-Filtered Electron Microscopy (EFEM) of Frozen Hydrated Biological Specimens." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 274–75. http://dx.doi.org/10.1017/s0424820100180124.

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The preparation of hydrated biological specimens for the use in a TEM has made a great stride foreward due to the work of Dubochet et al. on vitrification and Muller et al. on high pressure freezing. Transfer units and cryo stages for the microscopes allow imaging of specimens in the 100K range. Due to simple physical reasons, however, contrast of such kinds of specimen is still a problemm in conventional transmission electron microscopes (CTEM). Solutions as they are provided by an EFEM will be shown and explained in the following.Ice is the main constituent of frozen hydrated specimens. The large ratio of inelastic-to-elastic total cross section of 4.0 in case of ice which is even more than that for carbon results in an unavoidable high amount of inelastically scattered electrons. Blurred images and lacking contrast are due to that fact. The EEL spectra from a frozen hydrated section of biological material before and after freeze drying in the microscope document this fact. (Figure 1). Increased scattering probability and thickness contribute to the inelastic loss. In Figure 2 the EEL spectrum from a thin pure ice layer without any support is compared to the spectrum from thin freeze dried cryo section on a thin support. In case of ice the maximum of the low loss range is clearly shifted towards zero loss, mainly due to oxygen low loss and plasmon and to hydrogen core loss. Thus for the images shown in the following Figures a narrow energy window of 10 eV is used really to cut off all the inelastically scattered electrons.

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Bourke, Jay, and Christopher Chantler. "DFT and Plasmon-Coupling Models for Optical and Electronic Scattering Properties." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C381. http://dx.doi.org/10.1107/s2053273314096181.

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We present calculations and applications of optical energy loss data for use in studies of inelastic electron scattering in condensed matter systems. A new model of plasmon coupling and excitation broadening is implemented along with high-precision density functional theory to evaluate fundamental material properties critical to many areas of spectroscopic analysis. Recent developments in x-ray and electron spectroscopies have demonstrated critical dependence on low-energy electron scattering and optical loss properties, and significant discrepancies between theoretical and experimental scattering values [1]. Resolution of these discrepancies is required to validate experimental studies of material structures, and is particularly relevant to the characterization of small molecules and organometallic systems for which electron scattering data is often sparse or highly uncertain [2]. We have devised a new theoretical approach linking the optical dielectric function and energy loss spectrum of a material with its electron scattering properties and characteristic plasmon excitations. For the first time we present a model inclusive of plasmon coupling, allowing us to move beyond the longstanding statistical approximation and explicitly demonstrate the effects of band structure on the detailed behavior of bulk electron excitations in a solid or small molecule. This is a novel generalization of the optical response of the material, which we obtain using density functional theory [3]. We find that our developments improve agreement with experimental electron scattering results in the low-energy region (<~100 eV) where plasmon excitations are dominant; a region that is particularly crucial for structural investigations using x-ray absorption fine structure and electron diffraction. This work is further relevant to several commissions of the IUCr including the commissions on XAFS, International Tables, and Electron Crystallography.

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Eljarrat, Alberto, Lluís López-Conesa, César Magén, Žarko Gačević, Sergio Fernández-Garrido, Enrique Calleja, Sónia Estradé, and Francesca Peiró. "Insight into the Compositional and Structural Nano Features of AlN/GaN DBRs by EELS-HAADF." Microscopy and Microanalysis 19, no. 3 (May 9, 2013): 698–705. http://dx.doi.org/10.1017/s1431927613000512.

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AbstractIII-V nitride (AlGa)N distributed Bragg reflector devices are characterized by combined high-angle annular dark-field (HAADF) and electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope. Besides the complete structural characterization of the AlN and GaN layers, the formation of AlGaN transient layers is revealed using Vegard law on profiles of the position of the bulk plasmon peak maximum. This result is confirmed by comparison of experimental and simulated HAADF intensities. In addition, we present an advantageous method for the characterization of nano-feature structures using low-loss EELS spectrum image (EEL-SI) analysis. Information from the materials in the sample is extracted from these EEL-SI at high spatial resolution.The log-ratio formula is used to calculate the relative thickness, related to the electron inelastic mean free path. Fitting of the bulk plasmon is performed using a damped plasmon model (DPM) equation. The maximum of this peak is related to the chemical composition variation using the previous Vegard law analysis. In addition, within the context of the DPM, information regarding the structural properties of the material can be obtained from the lifetime of the oscillation. Three anomalous segregation regions are characterized, revealing formation of metallic Al islands.

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Normand, L., A. Thorel, and Y. Montardi. "Fantome: A calculation of the dielectric function from the plasmon excitation." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 990–91. http://dx.doi.org/10.1017/s0424820100172681.

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Electron Energy Loss Spectroscopy is now a well known method for chemical analysis(light elements especially), qualitative analysis of trace elements, EXELFS, etc. The low energy part of the spectrum can also be used in order to perform thickness evaluation and dielectric function determination. When EELS coupled with Transmission Electron Microscope, it presents the great interest of performing all measurements with a spatial resolution of the magnitude of the beam size. In the case of the dielectric function, we can then avoid any average effects due to macroscopic measurements. We then have access to the role of defaults, chemical heterogeneities, grain boundaries, anisotropy which can introduce major modifications in the macroscopic properties. The dielectric measurements are based on Kramers-Kronig analysis of the plasmon excitation (1, 2) ; A program (“Fantome”) has been written to process the EELS spectra. Results have been obtained on barium titanate.

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Kundmann, Michael K., and Gronsky Ronald. "Plasmon lineshape analysis in EELS of semiconductors." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 500–501. http://dx.doi.org/10.1017/s042482010010456x.

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Many materials display plasmon peaks in their low-loss EELS spectra. The plasmon peak shape, energy, and linewidth are characteristic of each material and are sensitive to the outer-shell electron density and details of the electronic band and energy-level structures. As these properties are a function not only of the composition but also the structure and chemistry of a sample, plasmon spectroscopy can potentially become a materials characterization tool which goes beyond the elemental analyses provided by EDXS and ionization-edge EELS. However, analysis of plasmon spectra requires considerably more sophistication than either of the aforementioned techniques due to the possibility of overlapping spectrum features, the prevalence of plural scattering, and the difficulty in detecting and characterizing the often subtle differences between the plasmon spectra of similar materials. As yet, no systematic approach to plasmon analysis analogous to that available commercially for EDXS or EELS core-edge analysis has been developed. We present here an approach which, for the simple case of semiconductors, makes some progress in this direction.

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Wang, Y. Y., Z. Shao, R. Ho, A. V. Somlyo, and A. P. Somlyo. "Quantitative EELS mapping of biological thin sections." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1568–69. http://dx.doi.org/10.1017/s0424820100132479.

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X-ray microanalysis and electron energy loss spectroscopy are reliable methods for determining at high spatial resolution the local composition of biological materials. EELS imaging, although potentially more sensitive than X-ray analysis, is complicated by the large background of EELS spectra. The conventional power law fitting of the EELS background can only be used for analysis of high concentrations and/or very thin sections (t< 0.3 λ) and it is not reliable for mapping low elemental concentrations. For the detection of low elemental concentrations at high spatial resolution, the background subtraction of the EELS spectrum and correction of long term microscope drift are critical, and limit the use of conventional energy filtered transmission electron microscopy. Therefore, we used energy filtered STEM with multiple least squares fitting, including the plural plasmon contribution to the background, to obtain quantitative phosphorus (P) and calcium (Ca) concentration maps of cryosections.The failure of the power law is due to the plural scattering contributions to the Background.

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Su, Yi-Feng, Jin G. Park, Ana Koo, Sarah Trayner, Ayou Hao, Rebekah Downes, and Richard Liang. "Characterization at Atomic Resolution of Carbon Nanotube/Resin Interface in Nanocomposites by Mapping sp2-Bonding States Using Electron Energy-Loss Spectroscopy." Microscopy and Microanalysis 22, no. 3 (June 2016): 666–72. http://dx.doi.org/10.1017/s1431927616000805.

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AbstractFunctionalization is critical for improving mechanical properties of carbon nanotubes (CNTs)/polymer nanocomposites. A fundamental understanding of the role of the CNT/polymer interface and bonding structure is key to improving functionalization procedures for higher mechanical performance. In this study, we investigated the effects of chemical functionalization on the nanocomposite interface at atomic resolution to provide direct and quantifiable information of the interactions and interface formation between CNT surfaces and adjacent resin molecules. We observed and compared electronic structures and their changes at the interfaces of nonfunctionalized and functionalized CNT/polymer nanocomposite samples via scanning transmission electron microscopy and electron energy-loss spectroscopy (EELS) spectrum imaging techniques. The results show that the state of sp2 bonding and its distribution at the CNT/resin interface can be clearly visualized through EELS mapping. We found that the functionalized CNT/polymer samples exhibited a lower fraction of sp2 bonding and a lower π*/σ* ratio compared with the nonfunctionalized cases. A good correlation between near-edge fine structures and low-loss plasmon energies was observed.

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Dadsetani, M., and A. R. Omidi. "Linear and nonlinear optical response in 3-nitroaniline: A DFT study for comparison between molecular and bulk phases." Journal of Nonlinear Optical Physics & Materials 24, no. 04 (December 2015): 1550047. http://dx.doi.org/10.1142/s0218863515500472.

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We have studied the electronic structure and optical responses of both molecular and bulk phases of 3-nitroaniline (m-NA) using density functional theory (DFT). We have developed our calculations within the framework of band structure theory for both phases. The results of current simulation are also useful for comparison between solids and vapors. Findings show that the crystalline m-NA has an indirect bandgap which is smaller than its molecular counterpart. Due to the weak intermolecular interactions, the crystalline band structure shows very low dispersions and hence the crystalline spectra are very similar to those of molecules, especially at lower energies. This resemblance is extended to lower wavelengths in linear regime, but limited to higher wavelengths in nonlinear one. This study shows that the substituent groups play major roles in the band structure and charge transfer excitations. The optical spectra show higher intensity and more splitting, especially in nonlinear regime, when we go from molecular phase to bulk phase. Findings show that the electron energy loss structures in vapor phase are very close to [Formula: see text], hence energy loss spectroscopy is a direct way for measuring dielectric function of vapors. According to our results, the crystalline phase exhibits plasmon resonances at much higher energies compared to those of vapor phase. For example, the energy loss spectrum of m-NA molecule shows plasmon peak around 17[Formula: see text]eV which is about 10[Formula: see text]eV lower than the crystalline counterpart. The comparison between nonlinear spectra and the linear spectra (as functions of both [Formula: see text] and 2[Formula: see text]) reveals the significant resemblance between linear and nonlinear structures in both phases. This study shows that the molecular-based models for investigating optical properties of organic crystals are only suitable for low energy regions. Finally, our simulation reproduces the experimental results very well.

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Miyabe, Yumiko, Tomoko Yoshida, Shunsuke Muto, and Tetsu Kiyobayashi. "Hydrogen Quasi-Chemically Trapped between Defective Graphene Layers in Nanostructured Graphite." Materials Science Forum 561-565 (October 2007): 1585–88. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.1585.

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Direct evidences of hydrogen loosely trapped between graphene layers in nanostructured graphite prepared by mechanical milling in a hydrogen atmosphere are presented, based on a combinational study of FT-IR, electron diffraction (ED) and electron energy-loss spectroscopy (EELS). The FT-IR spectrum of nanostructured graphite exhibited a new broad absorption band at very low frequencies around 660 cm-1, which almost disappeared by annealing up to 800 K. ED and plasmon peaks in EELS detected the unusual shrinkage and subsequent expansion of the fragmented graphene interlayer distance by hydrogen incorporation and desorption with annealing, well correlated with the change in intensity of the 660 cm-1 IR band. All the present results support our previous studies [S. Muto et al., Jpn. J. Appl. Phys. 44, 2061 (2005); T. Kimura et al, J. Alloys and Compounds 413, 150 (2006).].

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Shulga, Yury M., Eugene N. Kabachkov, Vitaly I. Korepanov, Igor I. Khodos, Dmitry Y. Kovalev, Alexandr V. Melezhik, Aleksei G. Tkachev, and Gennady L. Gutsev. "The Concentration of C(sp3) Atoms and Properties of an Activated Carbon with over 3000 m2/g BET Surface Area." Nanomaterials 11, no. 5 (May 17, 2021): 1324. http://dx.doi.org/10.3390/nano11051324.

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The alkaline activation of a carbonized graphene oxide/dextrin mixture yielded a carbon-based nanoscale material (AC-TR) with a unique highly porous structure. The BET-estimated specific surface area of the material is 3167 m2/g, which is higher than the specific surface area of a graphene layer. The material has a density of 0.34 g/cm3 and electrical resistivity of 0.25 Ω·cm and its properties were studied using the elemental analysis, transmission electron microscopy (TEM), electron diffraction (ED), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray induced Auger electron spectroscopy (XAES), and electron energy loss spectroscopy (EELS) in the plasmon excitation range. From these data, we derive an integral understanding of the structure of this material. The concentration of sp3 carbon atoms was found to be relatively low with an absolute value that depends on the measurement method. It was shown that there is no graphite-like (002) peak in the electron and X-ray diffraction pattern. The characteristic size of a sp2-domain in the basal plane estimated from the Raman spectra was 7 nm. It was also found that plasmon peaks in the EELS spectrum of AC-TR are downshifted compared to those of graphite.

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Zhang, Deng, Song, and Zhang. "Broadband Near-Infrared Absorber Based on All Metallic Metasurface." Materials 12, no. 21 (October 30, 2019): 3568. http://dx.doi.org/10.3390/ma12213568.

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Perfect broadband absorbers have increasingly been considered as important components for controllable thermal emission, energy harvesting, modulators, etc. However, perfect absorbers which can operate over a wide optical regime is still a big challenge to achieve. Here, we propose and numerically investigate a perfect broadband near-infrared absorber based on periodic array of four isosceles trapezoid prism (FITP) unit cell made of titanium (Ti) over a continuous silver film. The structure operates with low quality (Q) factor of the localized surface plasmon resonance (LSPR) because of the intrinsic high loss, which is the foundation of the broadband absorption. The high absorption of metal nanostructures mainly comes from the power loss caused by the continuous electron transition excited by the incident light inside the metal, and the resistance loss depends on the enhanced localized electric field caused by the FITP structure. Under normal incidence, the simulated absorption is over 90% in the spectrum ranging from 895 nm to 2269 nm. The absorber is polarization-independent at normal incidence, and has more than 80% high absorption persisting up to the incident angle of ~45° at TM polarization.

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Kundmann, Michael K., Ondrej L. Krivanek, and J. M. Martin. "Minimum-dose electron energy-loss spectroscopy." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 634–35. http://dx.doi.org/10.1017/s0424820100105230.

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Parallel-detection electron energy-loss spectrometers have greatly reduced the irradiation doses needed to acquire electron energy-loss spectroscopy (EELS) data. This raises the possibility that changes in chemical bonding due to radiation damage, which usually precede changes in composition, may be studied by examining alterations in low-loss and core-edge fine structure with increasing dose.The quality of data attainable with low-doses in parallel-detection EELS is illustrated by Fig. 1, which shows the K-edge region for a thin amorphous carbon film. This spectrum was collected in 2sec with a 1pm-diameter probe at 100kV in (microscope) diffraction mode. A 20cm camera length ensured that virtually all scattered electrons passed through the 3mm entrance aperture of the spectrometer. Spectrum dispersion is 3eV/channel and the energy resolution is ∼1eV/channel as the π* peak is clearly resolved. The total incident current, as determined in image mode (no objective aperture) from the viewing-screen meter, was only 40pA. The total dose for this K-edge spectrum was consequently only 6.4e-/Å2.

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Scott, C. P., A. J. Craven, C. J. Gilmore, and A. W. Bowen. "Background Fitting in the Low-Loss Region of Electron Energy Loss Spectra." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 56–57. http://dx.doi.org/10.1017/s0424820100133874.

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The normal method of background subtraction in quantitative EELS analysis involves fitting an expression of the form I=AE-r to an energy window preceding the edge of interest; E is energy loss, A and r are fitting parameters. The calculated fit is then extrapolated under the edge, allowing the required signal to be extracted. In the case where the characteristic energy loss is small (E < 100eV), the background does not approximate to this simple form. One cause of this is multiple scattering. Even if the effects of multiple scattering are removed by deconvolution, it is not clear that the background from the recovered single scattering distribution follows this simple form, and, in any case, deconvolution can introduce artefacts.The above difficulties are particularly severe in the case of Al-Li alloys, where the Li K edge at ~52eV overlaps the Al L2,3 edge at ~72eV, and sharp plasmon peaks occur at intervals of ~15eV in the low loss region. An alternative background fitting technique, based on the work of Zanchi et al, has been tested on spectra taken from pure Al films, with a view to extending the analysis to Al-Li alloys.

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Lazar, Sorin, Yang Shao, Lina Gunawan, Riad Nechache, Alain Pignolet, and Gianluigi A. Botton. "Imaging, Core-Loss, and Low-Loss Electron-Energy-Loss Spectroscopy Mapping in Aberration-Corrected STEM." Microscopy and Microanalysis 16, no. 4 (July 2, 2010): 416–24. http://dx.doi.org/10.1017/s1431927610013504.

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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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Holtz, Megan E., Yingchao Yu, Jie Gao, Héctor D. Abruña, and David A. Muller. "In Situ Electron Energy-Loss Spectroscopy in Liquids." Microscopy and Microanalysis 19, no. 4 (May 31, 2013): 1027–35. http://dx.doi.org/10.1017/s1431927613001505.

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AbstractIn situ scanning transmission electron microscopy (STEM) through liquids is a promising approach for exploring biological and materials processes. However, options for in situ chemical identification are limited: X-ray analysis is precluded because the liquid cell holder shadows the detector and electron energy-loss spectroscopy (EELS) is degraded by multiple scattering events in thick layers. Here, we explore the limits of EELS in the study of chemical reactions in their native environments in real time and on the nanometer scale. The determination of the local electron density, optical gap, and thickness of the liquid layer by valence EELS is demonstrated. By comparing theoretical and experimental plasmon energies, we find that liquids appear to follow the free-electron model that has been previously established for solids. Signals at energies below the optical gap and plasmon energy of the liquid provide a high signal-to-background ratio regime as demonstrated for LiFePO4 in an aqueous solution. The potential for the use of valence EELS to understand in situ STEM reactions is demonstrated for beam-induced deposition of metallic copper: as copper clusters grow, EELS develops low-loss peaks corresponding to metallic copper. From these techniques, in situ imaging and valence EELS offer insights into the local electronic structure of nanoparticles and chemical reactions.

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Reimer, L., R. Rennekamp, and A. Bakenfelder. "Electron spectroscopic imaging of thick crystalline specimens." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 412–13. http://dx.doi.org/10.1017/s0424820100154032.

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Electron spectroscopic imaging (ESI) by an energy-filtering electron microscope (EFEM, Zeiss EM902) shows the following advantages when compared with the unfiltered bright-field mode:1.The zero-loss image does not contain the contribution of inelastically scattered electrons. Though plasmon scattering shows a conversation of Bragg contrast - edge and bent contours and lattice defect images -, the angular distribution of inelastically scattered electrons results in a broader spectrum of excitation errors and a blurring of Bragg contrast.2.The zero-loss image avoids the chromatic aberration of inelastically scattered electrons for medium specimen thicknesses and can be applied so long as the intensity of the zero-loss peak in the electron energy-loss spectrum (EELS) is high enough for an exposure in a reasonable time (<100 s).3.Thick specimens with negligible zero-loss intensity can be imaged with an energy window at the highest multiple plasmon loss of the Poisson distribution or at the most probable energy of a Landau distribution. The angular distribution of electrons with these energy losses is so broad that the Bragg contrast is blurred, and the contrast is only caused by anomalous absorption effects similar to multi-beam images in the STEM mode when using a large probe aperture.

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Rez, P., and N. K. Menon. "Inner Shell Edge Jump Ratios in Electron Energy Loss Spectrometry." Microscopy and Microanalysis 7, S2 (August 2001): 1170–71. http://dx.doi.org/10.1017/s1431927600031925.

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There has been considerable interest in recent years in simulating the complete electron energy loss (EELS) spectrum to help the analyst make suitable judgments on experimental parameters such as collection angles and acquisition times. The spectrum is characterised by edges that arise from the excitation of inner shell electrons to the first available empty state. The edge threshold is approximately given by the inner shell binding energy. Each edge sits on the background of the tails of all the edges from inner shell excitations of lower energy (see Figl). The background from plasmons decays very quickly with energy and even the broadest plasmon makes a negligible contribution to the intensity for losses above about 150eV. The visibility of an edge (and also the detectability of the corresponding element) can be related to the intensity of the edge compared to the background although it is more common to use the jump ratio, which is the ratio of the intensity in the region after the edge E+B to the intensity of the background in the edge region, B.

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Eljarrat, Alberto, Xavier Sastre, Francesca Peiró, and Sónia Estradé. "Density Functional Theory Modeling of Low-Loss Electron Energy-Loss Spectroscopy in Wurtzite III-Nitride Ternary Alloys." Microscopy and Microanalysis 22, no. 3 (February 12, 2016): 706–16. http://dx.doi.org/10.1017/s1431927616000106.

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AbstractIn the present work, the dielectric response of III-nitride semiconductors is studied using density functional theory (DFT) band structure calculations. The aim of this study is to improve our understanding of the features in the low-loss electron energy-loss spectra of ternary alloys, but the results are also relevant to optical and UV spectroscopy results. In addition, the dependence of the most remarkable features with composition is tested, i.e. applying Vegard’s law to band gap and plasmon energy. For this purpose, three wurtzite ternary alloys, from the combination of binaries AlN, GaN, and InN, were simulated through a wide compositional range (i.e., AlxGa1−xN, InxAl1−xN, and InxGa1−xN, with x=[0,1]). For this DFT calculations, the standard tools found in Wien2k software were used. In order to improve the band structure description of these semiconductor compounds, the modified Becke–Johnson exchange–correlation potential was also used. Results from these calculations are presented, including band structure, density of states, and complex dielectric function for the whole compositional range. Larger, closer to experimental values, band gap energies are predicted using the novel potential, when compared with standard generalized gradient approximation. Moreover, a detailed analysis of the collective excitation features in the dielectric response reveals their compositional dependence, which sometimes departs from a linear behavior (bowing). Finally, an advantageous method for measuring the plasmon energy dependence from these calculations is explained.

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Siangchaew, K., D. Arayasantiparb, and M. Libera. "Electron Energy-Loss Spectrum Profiling of Polymer-Polymer Interfaces." Microscopy and Microanalysis 3, S2 (August 1997): 951–52. http://dx.doi.org/10.1017/s1431927600011648.

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The spatially-resolved structure and composition of amorphous or semicrystalline polymer-polymer interfaces are poorly understood. The absence of atomic-level periodicity precludes many of the transmission electron-optical techniques that have been so fruitful in studying interfaces in polycrystalline inorganic materials. Similarly, there has been relatively little work done on spatially-resolved spectroscopic analysis of polymer-polymer interfaces to determine chemical widths, largely because of concerns over electron-beam damage. Digital microscope control and parallel spectral acquisition provide for low-dose exposure, quantification of dose, and efficient data collection which open new windows to study polymer interfaces.This research is studying various multiphase polymer systems by focused-probe spectroscopic analysis to identify appropriate spectral features, data acquisition protocols, and background-modeling/data-processing algorithms in order to establish chemical widths characteristic of specific polymer-polymer interfaces (1). This research uses a 200keV Philips CM20 FEG TEM/STEM with a Gatan 666 PEELS spectrometer and an Emispec digital data acquisition/control system.

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Hunt, E. M., Z. L. Wang, N. D. Evans, and J. M. Hampikian. "Imaging of Metallic Nano-Particles Using PlasmOn/Valence Energy Loss Electrons." Microscopy and Microanalysis 3, S2 (August 1997): 1001–2. http://dx.doi.org/10.1017/s1431927600011892.

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Although crystal lattices can be determined reasonably well using high-resolution electron microscopy, determination of local chemistry at high spatial-resolution remains a challenge. An energy-filtering system has made it possible to perform chemically sensitive imaging in a transmission electron microscope (TEM). This type of imaging usually relies on the signal of the inner shell ionization edge, the intensity of which is affected by the threshold energy-loss and the ionization cross-section of the edge. Therefore, the spatial resolution of a core loss image image is strongly affected by the signal-to-noise ratio. In this respect, lower loss electrons from the plasmon or valence region of the energy loss spectrum (10-100 eV) are favorable for chemically sensitive imaging due to the much higher signal intensity, provided any delocalization effects are small in comparison to the required spatial resolution. Compositionally sensitive imaging using the aluminum plasmon energy-loss electrons has been shown to produce ∼2nm resolution for an atomically sharp Al/Ti interface.

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Horio, Y., Y. Urakami, and Y. Hashimoto. "Inelastic Scattering Components in the Si(111)-(7×7) RHEED Pattern by the Energy Filtering Method." Surface Review and Letters 05, no. 03n04 (June 1998): 755–60. http://dx.doi.org/10.1142/s0218625x98001134.

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Energy loss spectra for several parts of the Si(111)-(7 × 7) RHEED pattern, the (0 0) specular spot, the (3/7 3/7) superspot in the zeroth Laue zone, the (0 1) fundamental spot in the first Laue zone, and the Kikuchi line and background have been measured by the recently developed retarding type energy filter in the condition of the [Formula: see text] azimuth with a 10 kV incident electron beam. It was found that there are some differences in their spectra. Energy loss spectra of the (0 0) and (3/7 3/7) spots show surface plasmon loss peaks of silicon dominantly, and the spectrum of the (0 1) spot shows the same but includes weak bulk plasmon peaks. The spectrum of the Kikuchi line mainly shows bulk plasmon peaks and that of the background has no distinct structure in the profile. Glancing angle dependences of their profiles were also measured and discussed. The experimental data show that there is a relation between the quasielastic component of the diffraction beam and the pass length of the electron beam in a vacuum region near the surface where the electron interacts with the surface plasmon. The quasielastic component of the diffraction beam decreases as the incident glancing angle and/or takeoff angle become grazing.

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Bose, S. M. "Low energy plasmon peaks in the electron energy loss spectra of single-wall carbon nanotubes." Physics Letters A 289, no. 4-5 (October 2001): 255–56. http://dx.doi.org/10.1016/s0375-9601(01)00585-0.

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Narayan, Raman D., J. K. Weiss, and Peter Rez. "Highly Automated Electron Energy-Loss Spectroscopy Elemental Quantification." Microscopy and Microanalysis 20, no. 3 (April 10, 2014): 798–806. http://dx.doi.org/10.1017/s1431927614000567.

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AbstractA model-based fitting algorithm for electron energy-loss spectroscopy spectra is introduced, along with an intuitive user-interface. As with Verbeeck & Van Aert, the measured spectrum, rather than the single scattering distribution, is fit over a wide range. An approximation is developed that allows for accurate modeling while maintaining linearity in the parameters that represent elemental composition. Also, a method is given for generating a model for the low-loss background that incorporates plural scattering. Operation of the user-interface is described to demonstrate the ease of use that allows even nonexpert users to quickly obtain elemental analysis results.

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Wang, Xiaoyi, Marie-Pierre Chauvat, Pierre Ruterana, and Thomas Walther. "Investigation of phase separation in InGaN alloys by plasmon loss spectroscopy in a TEM." MRS Advances 1, no. 40 (2016): 2749–56. http://dx.doi.org/10.1557/adv.2016.542.

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ABSTRACTPhase separation of InxGa1-xN alloys into Ga-rich and In-rich regions was observed by a number of research groups for samples grown with high indium content, x. Due to the radiation sensitivity of InGaN to beam damage by fast electrons, high-resolution imaging in transmission electron microscopy (TEM) or core-loss electron energy-loss spectroscopy (EELS) may lead to erroneous results. Low-loss EELS can yield spectra of the plasmon loss regions at much lower electron fluxes. Unfortunately, due to their delayed edge onset, the low energetic core losses of Ga and In partially overlap with the plasmon peaks, all of which shift with indium content.Here we demonstrate a method to quantify phase separation in InGaN thin films from the low-loss region in EELS by simultaneously fitting both plasmon and core losses over the energy range of 13-30eV. Phase separation is shown to lead to a broadening of the plasmon peak and the overlapping core losses, resulting in an unreliable determination of the indium concentration from analyzing the plasmon peak position alone if phase separation is present. For x=0.3 and x=0.59, the relative contributions of the binary compounds are negligibly small and indicate random alloys. For xnom.=0.62 we observed strong broadening, indicating phase separation.

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Cueva, Paul, Robert Hovden, Julia A. Mundy, Huolin L. Xin, and David A. Muller. "Data Processing for Atomic Resolution Electron Energy Loss Spectroscopy." Microscopy and Microanalysis 18, no. 4 (June 15, 2012): 667–75. http://dx.doi.org/10.1017/s1431927612000244.

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AbstractThe high beam current and subangstrom resolution of aberration-corrected scanning transmission electron microscopes has enabled electron energy loss spectroscopy (EELS) mapping with atomic resolution. These spectral maps are often dose limited and spatially oversampled, leading to low counts/channel and are thus highly sensitive to errors in background estimation. However, by taking advantage of redundancy in the dataset map, one can improve background estimation and increase chemical sensitivity. We consider two such approaches—linear combination of power laws and local background averaging—that reduce background error and improve signal extraction. Principal component analysis (PCA) can also be used to analyze spectrum images, but the poor peak-to-background ratio in EELS can lead to serious artifacts if raw EELS data are PCA filtered. We identify common artifacts and discuss alternative approaches. These algorithms are implemented within the Cornell Spectrum Imager, an open source software package for spectroscopic analysis.

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Schattschneider, P., and F. Hofer. "Angle-Resolved Energy-Loss Spectra of Gd2O3." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 20–21. http://dx.doi.org/10.1017/s0424820100133692.

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Energy loss spectra of heavy rare earths oxides show two well defined plasmon-like peaks below 40 eV and some intensity variation beyond. Since the high-energy maximum is at about twice the energy as the low-energy maximum, double scattering contributions may mask the former. This effect induces artifacts when one attempts to determine the dielectric function ε(ω) from Kramers-Kronig-analysis (KKA) of the loss spectrum. Knowledge of ε(ω) allows to heuristically assign interband transitions or plasma excitations to particular maxima. Measurements in diffraction mode allow detection of dispersive features in ε(ω,q).Polycrystalline Gd2O3-films of of 40 nm thickness were investigated at 120 kV in a Philips EM420, attached to which is a Gatan 607 Spectrometer. Spectra were taken in diffraction mode (image coupling) at 8 scattering angles with a q-resolution of ≈ 0.03 Å-1. Energy resolution was ≈ 2 eV. The spectra were combined to a q-dependent loss function, using aperture correction.

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Roth, Friedrich, Andreas König, Christian Kramberger, Thomas Pichler, Bernd Büchner, and Martin Knupfer. "Challenging the nature of low-energy plasmon excitations in CaC 6 using electron energy-loss spectroscopy." EPL (Europhysics Letters) 102, no. 1 (April 1, 2013): 17001. http://dx.doi.org/10.1209/0295-5075/102/17001.

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Cross, Nicholas, Lei Liu, Ali Mohsin, Gong Gu, and Gerd Duscher. "Peculiar Plasmon Peak Position in Electron Energy Loss Spectrum of Hexagonal Boron Nitride/Graphene Double Layer." Microscopy and Microanalysis 21, S3 (August 2015): 985–86. http://dx.doi.org/10.1017/s1431927615005723.

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40

Rocca, M., F. Biggio, and U. Valbusa. "Surface-plasmon spectrum of Ag(001) measured by high-resolution angle-resolved electron-energy-loss spectroscopy." Physical Review B 42, no. 5 (August 15, 1990): 2835–41. http://dx.doi.org/10.1103/physrevb.42.2835.

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41

Bell, David C. "Imaging of Elastic and Inelastic Electron Scattering in Diamond." Microscopy and Microanalysis 3, S2 (August 1997): 1003–4. http://dx.doi.org/10.1017/s1431927600011909.

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The physical properties of diamond are some of the most interesting of natural materials. Electron energy-loss spectroscopy studies of a single crystal diamond wedge allow some of the basic electron matter interactions to be studied. The electron energy-loss spectrum has been examined with particular reference to the plasmon excitations in the crystal. The mean-free path of the electrons through the diamond crystal and the nature of the observed features in the energy-loss spectrum have been examined.A single crystal of diamond was cut and polished to produce a diamond wedge with a 33° angle making it suitable for observation in a transmission electron microscope (Fig. 1). The determination of the geometrical parameters of the crystal wedge involved the analysis of pendellosung fringes (Fig. 2) and comparisons to bloch wave calculations. The gradient analysis plot shown in Fig. 3 allowed the wedge thickness to be determined at any distance from the edge.

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42

Liu, J., and J. M. Cowley. "Valence electron energy loss spectroscopy in reflection geometry." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 378–79. http://dx.doi.org/10.1017/s0424820100153865.

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The low energy loss region of a EELS spectrum carries information about the valence electron excitation processes (e.g., collective excitations for free electron like materials and interband transitions for insulators). The relative intensities and the positions of the interband transition energy loss peaks observed in EELS spectra are determined by the joint density of states (DOS) of the initial and final states of the excitation processes. Thus it is expected that EELS in reflection mode could yield information about the perturbation of the DOS of the conduction and valence bands of the bulk crystals caused by the termination of the three dimensional periodicity at the crystal surfaces. The experiments were performed in a Philipps 400T transmission electron microscope operated at 120 kV. The reflection EELS spectra were obtained by a Gatan 607 EELS spectrometer together with a Tracor data acquisition system and the resolution of the spectrometer was about 0.8 eV. All the reflection spectra are obtained from the specular reflection spots satisfying surface resonance conditions.

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Krivanek, Ondrej L. "Progress in parallel-detection electron energy loss spectroscopy." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 660–61. http://dx.doi.org/10.1017/s0424820100105369.

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Parallel-detection electron energy loss spectrometers improve the detection efficiency by several hundred times compared to the traditional serial-detection spectrometers, but they have their own set of difficulties, such as the limited dynamic range of solid state detectors, the possibility of stray reflections of the intense zero loss beam giving rise to spurious background, and channel-to-channel gain variation. Fortunately, none of these difficulties is turning out to be insoluble. Here we report on improvements of the Gatan 666 parallel detection electron spectrometer in the areas of increasing the dynamic range of the detector, and in eliminating stray reflections.The increase in the dynamic range of the detector was needed especially for low energy losses (high spectral intensities), which usually saturated the detector even at the minimum acquisition time of 12 msecs. Accordingly, we have developed an electron attenuator which uses a magnetic dipole to sweep the spectrum across the detector perpendicular to the dispersion direction (Fig. 1).

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Asayama, Kyoichiro, Naoto Hashikawa, Tadashi Yamaguchi, Shohei Terada, and Hirotaro Mori. "Polymorphs Discrimination of Nickel Silicides in Device Structure by Improved Analyses of Low Loss Electron Energy Loss Spectrum." Japanese Journal of Applied Physics 46, No. 22 (June 1, 2007): L528—L530. http://dx.doi.org/10.1143/jjap.46.l528.

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VASYLYEV, M. A., and V. A. TINKOV. "LOW ENERGY ELECTRON INDUCED PLASMON EXCITATIONS IN THE ORDERING Pt80Co20(111) ALLOY SURFACE." Surface Review and Letters 15, no. 05 (October 2008): 635–40. http://dx.doi.org/10.1142/s0218625x08011809.

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Surface and bulk plasmon excitations from the ordering Pt 80 Co 20(111) alloy surface are studied by means electron energy loss spectroscopy in the low energy range of the primary electron energy E0. Deviation of the plasmon excitations from the theoretical value was found for Pt , Co metals, and Pt 80 Co 20(111) alloy as calculated in the free-electron gas model. For the ordered alloy, the bulk plasmon energy is 2–3 eV more than for the disordered alloy, whereas the difference for surface plasmon energy is 4–7 eV in the range E0 = 150–800 eV. The ration of intensity lines of plasmons η from E0 was investigated for the (dis)ordered state of the Pt 80 Co 20(111) alloy surface. For the ordered alloy, η has prolonged dependence from energy E0 in comparison with the disordered alloy. The relationship between layer-by-layer surface concentration and surface plasmon damping was observed.

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Ogawa, Teiichiro, Toshifumi Yoshidome, and Hirofumi Kawazumi. "Electron Energy-Loss Spectrum of Methanol. Observation of Singlet-Triplet Transitions at Low Incident Energy." Chemistry Letters 19, no. 1 (January 1990): 115–18. http://dx.doi.org/10.1246/cl.1990.115.

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Lemelin, V., A. D. Bass, and L. Sanche. "Low energy (6–18 eV) electron scattering from condensed thymidine (dT) III: absolute electronic excitation cross sections." Physical Chemistry Chemical Physics 22, no. 16 (2020): 8364–72. http://dx.doi.org/10.1039/d0cp00198h.

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48

Evans, N. D., and Z. L. Wang. "Separating the surface and volume plasmon energy loss intensity distributions in MgO and MgAl2O4." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1256–57. http://dx.doi.org/10.1017/s0424820100130912.

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Broadening on the low energy side of the MgAl2O4 (spinel) volume plasmon, which increases with decreasing sample thickness (Fig. 1a), affected multiple least squares (MLS) fitting when spectra such as these were used in quantitative analysis. The inverse dependency of broadening on thickness is indicative of a surface effect. Potential artifacts from sample preparation (argon milling) were investigated. Spinel stock was ground in methanol on a grinding disk of 15μm-diameter diamond, and the tailings were placed onto a holey-carbon film. Electron-transparent regions of spinel that extended beyond holes in the film were used to obtain the energy loss single scattering distributions (SSD) shown in Fig. 1b. Parallel-detection electron energy loss spectroscopy (PEELS) was performed at 100 kV with a Philips EM400T/FEG analytical electron microscope. These SSD were obtained using the procedures described earlier, and show, relative to those in Fig. 1a, identical broadening on the left side of the plasmon with decreasing specimen thickness. This similarity indicates the broadening effect is not due to milling but to surface plasmon excitation.

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Reichelt, R., A. Engel, and R. Leapman. "Electron energy loss spectroscopy (EELS) by scanning transmission electron microscopy (STEM) at low doses." Proceedings, annual meeting, Electron Microscopy Society of America 45 (August 1987): 116–17. http://dx.doi.org/10.1017/s0424820100125518.

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A scanning transmission electron microscope (STEM) has the unique feature to record simultaneously two types of images with high collection efficiencies. The first type, collected by an annular detector (AD), contains high resolution structural information which is primarily transmitted by elastically scattered electrons. The second type, formed by an electron spectrometer (SP), yields information on the local energy loss spectrum of the inelastically scattered electrons at lower structural resolution. Thus useful quantitative information from biological matter can be obtained: the AD-signal provides the basis for mass mapping and the inelastic one allows the estimation of the local chemical element concentration.For a very thin specimen (T<< ^, T: thickness, A: mean free path between two scattering events) the signal S of the imaging modes mentioned above can be linearly related to the properties of the sample:

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Zhu, Jiangtao, Peter A. Crozier, Peter Ercius, and James R. Anderson. "Derivation of Optical Properties of Carbonaceous Aerosols by Monochromated Electron Energy-Loss Spectroscopy." Microscopy and Microanalysis 20, no. 3 (April 15, 2014): 748–59. http://dx.doi.org/10.1017/s143192761400049x.

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AbstractMonochromated electron energy-loss spectroscopy (EELS) is employed to determine the optical properties of carbonaceous aerosols from the infrared to the ultraviolet region of the spectrum. It is essential to determine their optical properties to understand their accurate contribution to radiative forcing for climate change. The influence of surface and interface plasmon effects on the accuracy of dielectric data determined from EELS is discussed. Our measurements show that the standard thin film formulation of Kramers−Kronig analysis can be employed to make accurate determination of the dielectric function for carbonaceous particles down to about 40 nm in size. The complex refractive indices of graphitic and amorphous carbon spherules found in the atmosphere were determined over the wavelength range 200–1,200 nm. The graphitic carbon was strongly absorbing black carbon, whereas the amorphous carbon shows a more weakly absorbing brown carbon profile. The EELS approach provides an important tool for exploring the variation in optical properties of atmospheric carbon.

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Journal articles on the topic 'Low loss plasmon electron energy loss spectrum'

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