Quantitative Energy-filtering Transmission Electron Microscopy in Materials Science

Grogger, Werner; Hofer, Ferdinand; Warbichler, Peter; Kothleitner, Gerald

doi:10.1007/s100059910014

Cited by 17 publications

(6 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, EFTEM can be used to obtain thickness maps that provide information about the third dimension of samples in addition to the two‐dimension projections seen in bright‐field images. EFTEM has been widely used in materials and biological sciences (Leapman & Hunt, 1995; Beckers et al ., 1996; Hofer et al ., 1996, 2000; Grogger et al ., 2000). However, applications of EFTEM in coal fly ash studies are limited.…”

Section: Introductionmentioning

confidence: 99%

Characterization of ultrafine coal fly ash particles by energy‐filtered TEM

Chen

Shah

Huggins

et al. 2005

Journal of Microscopy

View full text Add to dashboard Cite

SummaryIn this study, energy-filtered transmission electron microscopy is demonstrated to be a valuable tool for characterizing ultrafine coal fly ash particles, especially those particles encapsulated in or associated with carbon. By examining a series of elemental maps (K-edge maps of C and O, and L-edge maps of Si, Al, Ti and Fe) recorded using the three-window method, considerable numbers of titanium and iron species with sizes from several nanometres to submicrometre were shown to be present, typically as oxides dispersed in the carbonaceous matrix. Crystalline phases, such as rutile and iron-rich oxide spinel, were also identified from electron diffraction patterns and highresolution TEM images. Information about these ultrafine coal fly ash particles regarding their size, morphology, elemental composition and distribution, and crystalline phases, which has not been available previously in conventional ash studies, should be useful in toxicological studies and related environmental fields.

show abstract

Section: Introductionmentioning

confidence: 99%

Characterization of ultrafine coal fly ash particles by energy‐filtered TEM

Chen

Shah

Huggins

et al. 2005

Journal of Microscopy

View full text Add to dashboard Cite

show abstract

“…Electron energy-loss spectroscopy ͑EELS͒ and energyfiltered transmission microscopy are now established as important tools for high-resolution chemical and physical characterization of new materials. [1][2][3] The chemical information is provided by energy losses involving core electrons, in the range from 50 to 1000 eV. The low-loss spectrum below 50 eV is dominated by bulk and surface plasmons involving valence electrons.…”

Section: Introductionmentioning

confidence: 99%

Relativistic effects in EELS of nanoporous alumina membranes

et al. 2003

View full text Add to dashboard Cite

Electrochemically prepared porous alumina membranes with a pore diameter of 58 nm have been investigated by electron energy-loss spectroscopy in a transmission electron microscope operated at 120 keV and 200 keV. Energy-loss spectra are recorded for electrons traveling along the pores at different impact parameters. The dominant spectral features near the pore wall are shown to originate in the excitation of surface plasmons. Additional loss features at 7 eV ͑8 eV͒ for 200 keV ͑120 keV͒ are observed, whose origin is associated to Cherenkov radiation modified by the sample nanostructure. Maxwell equations are solved for different geometrical models of the target, providing a good qualitative description of the experimental spectra. Quantitative agreement is obtained by considering multiple plasmon excitation, suggesting a promising tool to investigate pore surfaces.

show abstract

“…Such plural scattering effect can easily be removed by using the Fourierlog deconvolution [37]. The relationship between single-scattering spectrum S(E) and the energy-loss function Im[-1 / e(E)] is given as (4) where I 0 is the zero-loss intensity, t the specimen thickness, a 0 the first Bohr radius, m 0 the electron mass, b the collection semi-angle, and q E = E / (gm 0 v 2 ) the characteristic scattering angle for an energy loss E. The real part of the dielectric function is related to the imaginary part by the Kramers-Kronig transformation [38] ( 5) where P is the Cauchy principle part of the integral avoiding the pole at E = E¢. Providing that the thickness of BD is known, the real and imaginary parts of the dielectric function of BD can be deduced from the S(E) by using eqs (4) and (5).…”

Section: Dielectric Function Analyses From Kramers-kronig Transformatmentioning

confidence: 99%

“…The extrapolated thickness of the BD from C to D varies roughly from 70 to 20 nm. The maps of the dielectric functions (e 1 and e 2 ) of BD / Si 3 N 4 / SiO 2 / Si can then be determined using eqs (4) and (5) by providing information from the thickness map. Such information is obtained from the t / l map in Fig.…”

Section: S E ( )mentioning

confidence: 99%

“…Energy-filtered transmission electron microscopy (EFTEM) has become a very useful tool in characterizing material properties, because it allows the study of local chemical and electronic properties of a specimen at nanometre level spatial resolution [1][2][3][4]. Conventional EFTEM techniques utilize only two-or three-window methods to extract a two-dimensional elemental map [5,6] from inner-shell ionization edges occurring in electron energy-loss spectroscopy (EELS) spectrum.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Four-dimensional dielectric property image obtained from electron spectroscopic imaging series

Lo¹

2001

Journal of Electron Microscopy

View full text Add to dashboard Cite

We have demonstrated a new quantitative method to characterize two-dimensional distributions of energy-dependent dielectric function of materials from low loss electron spectroscopic image (ESI) series. Two problems associated with extracted image-spectrum from the low-loss image series, under-sampling and loss of energy resolution, were overcome by using fast Fourier transformation (FFT) interpolation and maximum entropy deconvolution method. In this study, Black Diamond/Si3N4/SiO2/Si-substrate dielectric layer designed for copper metallization was used as the sample. We show that the reconstructed (FFT interpolated and maximum entropy deconvoluted) image-spectrum obtained from ESI series images can be quantified with the same accuracy as conventional electron energy-loss spectroscopy spectra. Since the analysis of the dielectric function is sensitive to the local thickness of the specimen using Kramers-Kronig analysis, we also developed a new method to quantitatively determine the dielectric constant for low-k materials. We have determined the thickness of the Black Diamond using the extrapolated thickness method from the materials of known dielectric constants. Using Kramers-Kronig formula, the dielectric function map can be deduced from two-dimensional reconstructed single scattering spectra with providing the information of thickness. We proposed a four-dimensional data presentation for revealing the uniformity of the energy dependent property. The accuracy of our methods depends on the thickness determination and on the quality of the reconstructed spectra from the image series.

show abstract

Quantitative Energy-filtering Transmission Electron Microscopy in Materials Science

Cited by 17 publications

References 45 publications

Characterization of ultrafine coal fly ash particles by energy‐filtered TEM

Characterization of ultrafine coal fly ash particles by energy‐filtered TEM

Relativistic effects in EELS of nanoporous alumina membranes

Four-dimensional dielectric property image obtained from electron spectroscopic imaging series

Contact Info

Product

Resources

About