scholarly journals A METHOD OF TEMPERATURE CORRECTION FOR ELECTRON TUNNELING SPECTRUM

1986 ◽  
Vol 35 (3) ◽  
pp. 393
Author(s):  
LI HONG-CHENG ◽  
WANG RUI-LAN ◽  
WANG PING-SHU ◽  
GUAN WEI-YAN
Keyword(s):  
Electron Tunneling ◽  
Temperature Correction ◽  
Tunneling Spectrum

Molecular Degradation in the Electron Microscope: A Tunneling Spectroscopy Study

1975 ◽  
Vol 33 ◽  
pp. 244-245
Author(s):  
M. Parikh ◽  
P. K. Hansma
Keyword(s):  
Electron Microscope ◽  
Electron Tunneling ◽  
Physical Structure ◽  
Tunneling Spectroscopy ◽  
Inelastic Electron ◽  
Tunneling Spectrum ◽  
Inelastic Electron Tunneling Spectroscopy ◽  
Loss Analysis ◽  
Inelastic Electron Tunneling ◽  
Electron Tunneling Spectroscopy

Molecular degradation in the electron microscope has been studied by energy loss spectroscopy, mass loss analysis and other techniques; none of these, however, have provided explicit information about the changes in the physical structure of the molecules. Here we present results from the use of inelastic electron tunneling spectroscopy as a probe in the study of degradation of molecular specimens in an electron microscope. The technique involves including the molecules of interest in a metal-insulatormetal junction and then monitoring the junctions current-voltage (I-V) characteristic. Explicitly, the measurement of d2I/dV2 vs. V provides a spectrum of vibrational frequencies (related to IR and Raman active modes) of the molecule; thus information about molecular bonds and physical configuration can be obtained. Upon electron irradiation, changes in the molecular structure are visible as changes in the heights and positions of the peaks in the tunneling spectrum.

scholarly journals Effects of electron-phonon interactions on the electron tunneling spectrum of PbS quantum dots

2015 ◽  
Vol 92 (4) ◽  
Author(s):  
H. Wang ◽  
E. Lhuillier ◽  
Q. Yu ◽  
A. Mottaghizadeh ◽  
C. Ulysse ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electron Tunneling ◽  
Tunneling Spectrum ◽  
Pbs Quantum Dots

A TEM study of electron tunneling in biological macromolecules

1987 ◽  
Vol 45 ◽  
pp. 140-141
Author(s):  
J. A. Panitz
Keyword(s):  
Stark Effect ◽  
Electron Tunneling ◽  
Imaging Modality ◽  
Tunneling Current ◽  
Biological Species ◽  
Scanning Tunneling ◽  
Biological Macromolecules ◽  
Flat Surfaces ◽  
Virus Particles ◽  
Stm Images

Tunneling is a ubiquitous phenomenon. Alpha particle disintegration, the Stark effect, superconductivity in thin films, field-emission, and field-ionization are examples of electron tunneling phenomena. In the scanning tunneling microscope (STM) electron tunneling is used as an imaging modality. STM images of flat surfaces show structure at the atomic level. However, STM images of large biological species deposited onto flat surfaces are disappointing. For example, unstained virus particles imaged in the STM do not resemble their TEM counterparts.It is not clear how an STM image of a biological species is formed. Most biological species are large compared to the nominal electrode separation of ∼ 1nm that is required for electron tunneling. To form an image of a biological species, the tunneling electrodes must be separated by a distance that would normally be too large for a tunneling current to be observed.

Field-assisted ionization theory for microscopists

1994 ◽  
Vol 52 ◽  
pp. 820-821
Author(s):  
Patrick P. Camus
Keyword(s):  
Electric Field ◽  
Electron Tunneling ◽  
Ionization Probability ◽  
Critical Distance ◽  
Tunneling Probability ◽  
Field Ionization ◽  
Radius Of Curvature ◽  
Field Evaporation ◽  
A Value ◽  
Ion Emission

The theory of field ion emission is the study of electron tunneling probability enhanced by the application of a high electric field. At subnanometer distances and kilovolt potentials, the probability of tunneling of electrons increases markedly. Field ionization of gas atoms produce atomic resolution images of the surface of the specimen, while field evaporation of surface atoms sections the specimen. Details of emission theory may be found in monographs.Field ionization (FI) is the phenomena whereby an electric field assists in the ionization of gas atoms via tunneling. The tunneling probability is a maximum at a critical distance above the surface,xc, Fig. 1. Energy is required to ionize the gas atom at xc, I, but at a value reduced by the appliedelectric field, xcFe, while energy is recovered by placing the electron in the specimen, φ. The highest ionization probability occurs for those regions on the specimen that have the highest local electric field. Those atoms which protrude from the average surfacehave the smallest radius of curvature, the highest field and therefore produce the highest ionizationprobability and brightest spots on the imaging screen, Fig. 2. This technique is called field ion microscopy (FIM).

Sensing of dynamic charge states using single-electron tunneling transistors

1998 ◽  
Vol 168 (2) ◽  
pp. 219
Author(s):  
V.A. Krupenin ◽  
S.V. Lotkhov ◽  
H. Scherer ◽  
A.B. Zorin ◽  
F.-J. Ahlers ◽  
...  
Keyword(s):  
Electron Tunneling ◽  
Single Electron ◽  
Single Electron Tunneling ◽  
Dynamic Charge ◽  
Charge States
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