scholarly journals Chemical identification through two-dimensional electron energy-loss spectroscopy

2020 ◽  
Vol 6 (28) ◽  
pp. eabb4713
Author(s):  
Renwen Yu ◽  
F. Javier García de Abajo
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Electronic Device ◽  
Theoretical Calculations ◽  
Chemical Species ◽  
High Sensitivity ◽  
Two Dimensional ◽  
Excitation Spectra ◽  
Electron Energy Loss

We explore a disruptive approach to nanoscale sensing by performing electron energy loss spectroscopy through the use of low-energy ballistic electrons that propagate on a two-dimensional semiconductor. In analogy to free-space electron microscopy, we show that the presence of analyte molecules in the vicinity of the semiconductor produces substantial energy losses in the electrons, which can be resolved by energy-selective electron injection and detection through actively controlled potential gates. The infrared excitation spectra of the molecules are thereby gathered in this electronic device, enabling the identification of chemical species with high sensitivity. Our realistic theoretical calculations demonstrate the superiority of this technique for molecular sensing, capable of performing spectral identification at the zeptomol level within a microscopic all-electrical device.

Subcellular Localization of Fluorinated Serotonin in Human Platelets by Electron Energy-Loss Spectroscopy

1977 ◽  
Vol 35 ◽  
pp. 238-239
Author(s):  
J.L. Costa ◽  
D.C. Joy ◽  
D.M. Maher ◽  
K.L. Kirk ◽  
S.W. Hui
Keyword(s):  
Subcellular Localization ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
High Sensitivity ◽  
Spot Size ◽  
Human Platelets ◽  
Parent Molecule ◽  
Low Sensitivity ◽  
Electron Energy Loss

Fluorinated organic molecules have considerable potential as tracers in bio logical systems, since a number of fluorinated analogs demonstrate biological activity similar to that of the parent molecule1. To date, however, the subcellular localization of fluorine has been hampered by the relatively low sensitivity of conventional X-ray microanalysis systems to fluorine. Electron energy-loss spectroscopy, in contrast, is a very efficient method for detecting light elements. We have capitalized on the high sensitivity of this technique to fluorine to identify and localize fluorinated serotonin at a subcellular level in human platelets.Intact human platelets were incubated with 10-5 M concentrations of either serotonin (5HT) or 4,6 difluoroserotonin (DF5HT)2 for 30 minutes at 37°C. Following the incubation period, air-dried whole mounts3 were prepared on 200 mesh copper grids coated with collodion and carbon. Individual platelets were examined at 80 kv in the STEM mode (10 nm spot size), utilizing a Jeol 100B microscope equipped with a field emission gun, a scanning attachment, an electron spectrometer, and a Kevex analysis recording system.

Dipolar transformations of two-dimensional quantum dots arrays proven by electron energy loss spectroscopy

2012 ◽  
Vol 112 (2) ◽  
pp. 024105 ◽  
Author(s):  
R. E. Moctezuma ◽  
J. F. Nossa ◽  
A. Camacho ◽  
J. L. Carrillo ◽  
J. M. Rubí
Keyword(s):  
Quantum Dots ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Two Dimensional ◽  
Electron Energy Loss

Van der Waals forces for mica and quartz: calculations from complete dielectric data

1977 ◽  
Vol 353 (1673) ◽  
pp. 163-176 ◽  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Theoretical Calculations ◽  
Dielectric Data ◽  
Region 10 ◽  
Experimental Values ◽  
Electron Energy Loss ◽  
Theory And Experiment ◽  
Made In

By using dielectric data, based on electron energy loss spectroscopy, the Lifshitz-van der Walls force for interacting mica and quartz plates is calculated. Comparisons with experiment and earlier theoretical calculations are made. In the non-retarded region (≲10 nm ) experimental values for the Hamaker constant for mica are up to 50% higher than those obtained from Lifshitz theory. The agreement between theory and experiment is much better for distances of ca .100 nm. Various errors which may be responsible for the disagreement are discussed.

An examination of centrifugal barrier effects in iodine pentafluoride by inner shell electron energy loss spectroscopy

1994 ◽  
Vol 72 (11-12) ◽  
pp. 1093-1100
Author(s):  
Glyn Cooper ◽  
Wenzhu Zhang ◽  
C. E. Brion
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Shape Resonance ◽  
High Electron ◽  
Excitation Spectra ◽  
Experimental Conditions ◽  
Barrier Effects ◽  
Shell Electron ◽  
Electron Energy Loss

Electron energy loss spectroscopy was used to study the core (I 4d, I 3d, and F Is) level electronic excitation spectra of IF5. The spectra were collected under experimental conditions such that dipole transitions were dominant (high electron impact energy (3 keV) and 0° scattering angle). The spectra were assigned using term value arguments, and by analogy with those of the isoelectronic molecules TeF6 and XeF4. In common with the spectra of TeF6 and XeF4, the spectra of IF5 show features that are consistent with a centrifugal potential-barrier model. In particular, transitions to virtual valence orbitals and to above-edge shape resonance channels are relatively intense, whereas transitions to Rydberg orbitals are, in comparison, very weak or absent. As in the case of TeF6, it was necessary to include atomic 4f orbitals in the molecular orbital basis to adequately account for the continuum resonance features observed in the IF5 spectra. The valence shell electron energy loss spectrum of IF5 from 5 to 35 eV was also obtained.

Antimony Delta Doping by Scanning Transmission Electron Microscopy and Electron Energy Loss Spectroscopy

1999 ◽  
Vol 5 (S2) ◽  
pp. 614-615
Author(s):  
R.R. Vanfleet ◽  
D. Muller ◽  
H.-J. Gossmann ◽  
J. Silcox
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Spatial Resolution ◽  
Electron Energy Loss Spectroscopy ◽  
Two Dimensional ◽  
Layer Width ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

MBE techniques allow the fabrication of exceptionally sharp compositional changes such as delta doped layers in semiconductors. Producing these spatially confined doped layers is critical to many innovative device designs. The spatial confinement of these delta doped structures can be less than the measurement resolution of the currently standard SIMS and RBS techniques. This allows only the upper limits on the layer width to be measured. These SIMS and RBS methods are also inadequate for the two dimensional information desired for future device design and development. More recently developed techniques such as Scanning Capacitance Microscopy and spreading resistance measurement give two dimensional information but have similar spatial resolution issues. The Z-contrast nature of Annular Dark Field (ADF) imaging with the complimentary technique of Electron Energy Loss Spectroscopy (EELS) in the Scanning Transmission Electron Microscope (STEM) shows promise for two dimensional dopant profiling with spatial resolution on the atomic scale.

Chemical fingerprinting of polyvinyl acetate and polycarbonate using electron energy-loss spectroscopy

2020 ◽  
Vol 11 (34) ◽  
pp. 5484-5492
Author(s):  
Ruchi Pal ◽  
Laure Bourgeois ◽  
Matthew Weyland ◽  
Arun K. Sikder ◽  
Kei Saito ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Chemical Structure ◽  
Polyvinyl Acetate ◽  
Polymeric Materials ◽  
High Sensitivity ◽  
Chemical Fingerprinting ◽  
Electron Energy Loss

This work demonstrates that the high sensitivity of EELS can be used to identify the changes in the chemical structure of polymeric materials.

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