scholarly journals Low-energy transmission electron diffraction and imaging of large-area graphene

2017 ◽  
Vol 3 (9) ◽  
pp. e1603231 ◽  
Author(s):  
Wei Zhao ◽  
Bingyu Xia ◽  
Li Lin ◽  
Xiaoyang Xiao ◽  
Peng Liu ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Low Energy ◽  
Energy Transmission ◽  
Large Area ◽  
Transmission Electron Diffraction ◽  
Transmission Electron

Transmission Electron Diffraction at 200 eV and Damage Thresholds below the Carbon K Edge

2000 ◽  
Vol 6 (4) ◽  
pp. 368-379
Author(s):  
Michael R. Stevens ◽  
Qing Chen ◽  
Uwe Weierstall ◽  
John C.H. Spence
Keyword(s):  
Electron Diffraction ◽  
Cross Section ◽  
Single Molecule ◽  
Cross Sections ◽  
Threshold Energy ◽  
Low Energy ◽  
Transmission Electron Diffraction ◽  
Transmission Electron ◽  
Minimum Number ◽  
Shell Ionization

Abstract Transmission electron diffraction patterns from ultra-thin aromatic and aliphatic organic films at beam energies of 200 eV–1 keV have been recorded in a custom low energy electron transmission (LEET) chamber. A significant reduction of the molecular damage cross-section, measured by fading of diffraction spots, was found for thin films of the aromatic perylene when the beam energy was reduced from 400 to 200 eV. The corresponding measurements for the aliphatic tetracontane showed a smaller “threshold energy” and the differences are discussed. Electron beam damage from other aromatic materials has also been studied at low energy. Comparison of the carbon K shell ionization cross-section and the measured damage cross-sections show that carbon K-shell ionization is strongly correlated with the damage observed in aromatics at beam energies higher than 284 eV. Calculation of the minimum number of unit cells needed for imaging a single molecule, and comparison of calculated elastic with measured damage cross-sections both indicate new possibilities for imaging biomolecules with low energy electrons.

In-Situ Transmission Electron Microscopy Studies of the Oxidation of Si (111) 7X7

1989 ◽  
Vol 159 ◽  
Author(s):  
J.M. Gibson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Electron Diffraction ◽  
High Energy ◽  
Energy Transmission ◽  
Transmission Electron Diffraction ◽  
Transmission Electron

ABSTRACTThe kinematical approximation is valid for High-Energy Transmission Electron Diffraction from monolayers in planview. We use this fact to study quantitatively the attack of Si (111) 7×7 by 02. Oxygen is found to bind in the bridging position of the adatom backbonds and render the structure very stable during subsequent 02 exposure. Electron-beam exposure during dosing additionally creates rapid disordering which is presumed to represent SiOx formation.

Transmission Electron Diffraction at 200 eV and Damage Thresholds below the Carbon K Edge

2000 ◽  
Vol 6 (4) ◽  
pp. 368-379 ◽  
Author(s):  
Michael R. Stevens ◽  
Qing Chen ◽  
Uwe Weierstall ◽  
John C.H. Spence
Keyword(s):  
Electron Diffraction ◽  
Cross Section ◽  
Single Molecule ◽  
Cross Sections ◽  
Threshold Energy ◽  
Low Energy ◽  
Transmission Electron Diffraction ◽  
Transmission Electron ◽  
Minimum Number ◽  
Shell Ionization

AbstractTransmission electron diffraction patterns from ultra-thin aromatic and aliphatic organic films at beam energies of 200 eV–1 keV have been recorded in a custom low energy electron transmission (LEET) chamber. A significant reduction of the molecular damage cross-section, measured by fading of diffraction spots, was found for thin films of the aromatic perylene when the beam energy was reduced from 400 to 200 eV. The corresponding measurements for the aliphatic tetracontane showed a smaller “threshold energy” and the differences are discussed. Electron beam damage from other aromatic materials has also been studied at low energy. Comparison of the carbon K shell ionization cross-section and the measured damage cross-sections show that carbon K-shell ionization is strongly correlated with the damage observed in aromatics at beam energies higher than 284 eV. Calculation of the minimum number of unit cells needed for imaging a single molecule, and comparison of calculated elastic with measured damage cross-sections both indicate new possibilities for imaging biomolecules with low energy electrons.

Transmission Electron Diffraction Analysis by Computer

1970 ◽  
Vol 28 ◽  
pp. 40-41
Author(s):  
R.A. Ploc ◽  
G.H. Keech
Keyword(s):  
Electron Diffraction ◽  
Input Data ◽  
Reciprocal Lattice ◽  
Computer Programme ◽  
Transmission Electron Diffraction ◽  
Usual Procedure ◽  
Transmission Electron ◽  
Complex Shapes ◽  
Computer Input ◽  
Diffraction Effects

An unambiguous analysis of transmission electron diffraction effects requires two samplings of the reciprocal lattice (RL). However, extracting definitive information from the patterns is difficult even for a general orthorhombic case. The usual procedure has been to deduce the approximate variables controlling the formation of the patterns from qualitative observations. Our present purpose is to illustrate two applications of a computer programme written for the analysis of transmission, selected area diffraction (SAD) patterns; the studies of RL spot shapes and epitaxy.When a specimen contains fine structure the RL spots become complex shapes with extensions in one or more directions. If the number and directions of these extensions can be estimated from an SAD pattern the exact spot shape can be determined by a series of refinements of the computer input data.

Rocking Beam Microarea Diffraction Applied to Metallic thin Films

1976 ◽  
Vol 34 ◽  
pp. 396-397
Author(s):  
R. H. Geiss
Keyword(s):  
Thin Films ◽  
Electron Diffraction ◽  
Small Area ◽  
Objective Lens ◽  
Electron Optics ◽  
Metallic Thin Films ◽  
Transmission Electron Diffraction ◽  
Transmission Electron ◽  
Sample Height ◽  
Scanning Transmission

The theory and practical limitations of micro area scanning transmission electron diffraction (MASTED) will be presented. It has been demonstrated that MASTED patterns of metallic thin films from areas as small as 30 Åin diameter may be obtained with the standard STEM unit available for the Philips 301 TEM. The key to the successful application of MASTED to very small area diffraction is the proper use of the electron optics of the STEM unit. First the objective lens current must be adjusted such that the image of the C2 aperture is quasi-stationary under the action of the rocking beam (obtained with 40-80-160 SEM settings of the P301). Second, the sample must be elevated to coincide with the C2 aperture image and its image also be quasi-stationary. This sample height adjustment must be entirely mechanical after the objective lens current has been fixed in the first step.

scholarly journals Transmission Electron Diffraction From Nanoparticles, Nanowires and Thin Films in an SEM With Conventional EBSD Equipment

2010 ◽  
Vol 16 (S2) ◽  
pp. 1742-1743 ◽  
Author(s):  
RH Geiss ◽  
RR Keller ◽  
DT Read
Keyword(s):  
Thin Films ◽  
Electron Diffraction ◽  
Transmission Electron Diffraction ◽  
Transmission Electron

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

Laser-Induced Oxidation and Crystallization of Thin Amorphous Sputtered Cr Films

1983 ◽  
Vol 29 ◽  
Author(s):  
M. I. Birjega ◽  
C. A. Constantin ◽  
M. Dinescu ◽  
I. Th. Florescu ◽  
I. N. Mihailescu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Laser Irradiation ◽  
Dwell Time ◽  
Free Standing ◽  
Transmission Electron Diffraction ◽  
Oxidation Processes ◽  
Transmission Electron ◽  
Power Densities

ABSTRACTThe crystallization and oxidation processes of thin, free-standing (FS), sputtered Cr films under the action of cw CO2 laser irradiation were studied by transmission electron microscopy (TEM) and transmission electron diffraction (TED). The crystallization is induced at power densities above 28.65 W cm−2, dwell time of 1 s, and the oxidation at power densities of 48.1 W cm−2 and longer dwell times.

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