scholarly journals Investigation of Nanoelectrodes by Transmission Electron Microscopy

2001 ◽  
Vol 676 ◽  
Author(s):  
M. S. Kabir ◽  
S. H. Magnus Persson ◽  
Yimin Yao ◽  
Jean Phillippe Bourgoin ◽  
Serge Palacin
Keyword(s):  
Room Temperature ◽  
High Energy ◽  
Image Features ◽  
Electrical Characteristics ◽  
Conjugated Molecules ◽  
Atomic Force ◽  
Transmission Electron ◽  
High Energy Electrons ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

ABSTRACTElectrodes for making connections to single molecules and clusters must have separations smaller than 10 nm. They are therefore difficult or impossible to image with atomic force microscopes (AFM) or Scanning Electron Microscopes (SEM). We have fabricated nanoelelectrodes by different methods to contacts nanoclusters and conjugated molecules and investigated their properties in transmission electron microscope (TEM) and their electrical characteristics at room temperature and at 4.2K. The electrodes are made on SiN4 membranes, which is transparent to high energy electrons and which make it possible to image features of a few nanometers in TEM.

An ultrastructural study of the epicuticle of Ascaris suum

1991 ◽  
Vol 49 ◽  
pp. 306-307
Author(s):  
D. M. Ramnani ◽  
G. D. Cain
Keyword(s):  
Phosphate Buffer ◽  
Room Temperature ◽  
Body Wall ◽  
Intestinal Parasite ◽  
Ascaris Suum ◽  
Parasitic Nematodes ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Saline Medium

Ascaris suum, an intestinal parasite of swine, has a complex body wall, consisting of nine distinct layers when observed by transmission electron microscopy. The outermost layer of the cortex is a trilaminar region, the epicuticle, that is similar in appearance to plasma membrane. Parasitic nematodes interact with their hosts through this layer. The structure of the epicuticle is being studied with transmission and scanning electron microscopes.Parasites were obtained from an abattoir at Waterloo, Iowa, and maintained in Harpur's saline medium for up to two days. Cuticles were separated by microdissection and washed in 0.1M phosphate buffer, pH 7.2. Trump's universal fixative (4% Formaldehyde: 1% Glutaraldehyde in phosphate buffer, pH 7.2 ) was used for 1 h at room temperature for primary fixation. Surface charge of epicuticle was studied by incubating cuticle with cationized ferritin (Polysciences) at a concentration of lmg/ml in 0.1M phosphate buffer, pH 7.2, for 30 minutes at room temperature.

High-Energy Backscattered Electron Imaging of Voids in Aluminum Metallizations

1991 ◽  
Vol 225 ◽  
Author(s):  
D. M. Follstaedt ◽  
J. A. Van Den Avyle ◽  
A. D. Romig ◽  
J. A. Knapp
Keyword(s):  
Void Formation ◽  
High Energy ◽  
Backscattered Electron Imaging ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Backscattered Electron ◽  
Electron Microscopes ◽  
Al Metallization ◽  
Electron Imaging ◽  
Scanning Electron Microscopes

ABSTRACTBackscattered electron imaging of microcircuits in scanning transmission electron microscopes at 120 kV is shown to produce improved images of voids in passivated Al metallization lines relative to those obtained with scanning electron microscopes at ≤ 40 kV. At 120 kV, resolutions of about 0.1 μm are achieved for voids imaged beneath 1.0 μm glass overlayers. This technique allows improved characterization of microstructures for basic investigations of void formation and more accurate counting of voids in microcircuits without removing glass overlayers. Smaller voids should also be detectable with the higher voltage.

7-beam lattice images of (110) oriented Ge

1978 ◽  
Vol 36 (1) ◽  
pp. 290-291
Author(s):  
J.R. Parsons ◽  
C.W. Hoelke
Keyword(s):  
Image Features ◽  
Objective Lens ◽  
Lattice Plane ◽  
Lattice Image ◽  
Crystalline Defects ◽  
Transmission Electron ◽  
Lattice Images ◽  
Electron Microscopes ◽  
Structural Aspects ◽  
Beam Lattice

The direct imaging of a crystal lattice has intrigued electron microscopists for many years. What is of interest, of course, is the way in which defects perturb their atomic regularity. There are problems, however, when one wishes to relate aperiodic image features to structural aspects of crystalline defects. If the defect is inclined to the foil plane and if, as is the case with present 100 kV transmission electron microscopes, the objective lens is not perfect, then terminating fringes and fringe bending seen in the image cannot be related in a simple way to lattice plane geometry in the specimen (1).The purpose of the present work was to devise an experimental test which could be used to confirm, or not, the existence of a one-to-one correspondence between lattice image and specimen structure over the desired range of specimen spacings. Through a study of computed images the following test emerged.

Temperature Dependent Quasi-Periodic Facetting of AlAs Grown by MBE on (100) GaAs Substrates

1993 ◽  
Vol 312 ◽  
Author(s):  
Richard Mirin ◽  
Mohan Krishnamurthy ◽  
James Ibbetson ◽  
Arthur Gossard ◽  
John English ◽  
...  
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
High Energy Electron ◽  
Temperature Dependent ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Atomic Force ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Facet Formation

AbstractHigh temperature (≥ 650°C) MBE growth of AlAs and AlAs/GaAs superlattices on (100) GaAs is shown to lead to quasi-periodic facetting. We demonstrate that the facetting is only due to the AlAs layers, and growth of GaAs on top of the facets replanarizes the surface. We show that the roughness between the AlAs and GaAs layers increases with increasing number of periods in the superlattice. The roughness increases to form distinct facets, which rapidly grow at the expense of the (100) surface. Within a few periods of the initial facet formation, the (100) surface has disappeared and only the facet planes are visible in cross-sectional transmission electron micrographs. At this point, the reflection high-energy electron diffraction pattern is spotty, and the specular spot is a distinct chevron. We also show that the facetting becomes more pronounced as the substrate temperature is increased from 620°C to 710°C. Atomic force micrographs show that the valleys enclosed by the facets can be several microns long, but they may also be only several nanometers long, depending on the growth conditions.

Graphene in Titan

2021 ◽  
Author(s):  
Rahul Kumar Kushwaha ◽  
Ambresh Mallya ◽  
Dipen Sahu ◽  
Jaya Krishna Meka ◽  
Sheng-Lung Chou ◽  
...  
Keyword(s):  
Room Temperature ◽  
Laboratory Experiments ◽  
Vacuum Ultraviolet ◽  
Physical Nature ◽  
Potassium Bromide ◽  
Aromatic Molecules ◽  
Transmission Electron ◽  
Polycyclic Aromatic ◽  
Plasma Spectrometer ◽  
Electron Microscopes

<p>Benzene (C<sub>6</sub>H<sub>6</sub>) ice has been observed in the Titan’s stratosphere [1], and benzonitrile (C<sub>6</sub>H<sub>5</sub>CN) is a possible constituent in the benzene and nitrogen-rich environment of Titan’s atmosphere [2]. The energetic processing of such aromatic molecules can synthesize large and complex aromatic molecules such as the Polycyclic Aromatic Hydrocarbons (PAHs). To-date a number of laboratory experiments have reported the formation of complex organics from the energetic processing of aromatic molecules [3-6]. In particular, Scanning Electron Microscopy (SEM) micrographs of the residues resulting from irradiated benzene ices are found to contain geometrically shaped particles [6]. Therefore, by employing electron microscopes, we can understand the physical nature of the dust leftover from the aromatic molecule irradiation.</p> <p>In the present investigation, we subjected benzonitrile ice made at 4 K to vacuum ultraviolet (9 eV) radiation at two beamlines, BL03 and BL21A2 of Taiwan Light Source at NSRRC, Taiwan. After irradiation, the ice was warmed to room temperature, which left a brownish residue on the Potassium Bromide (KBr) substrate. The VUV spectrum of the residue is observed to have characteristic aromatic signatures. The residue is then transferred to a quantifoil grid for High-Resolution Transmission Electron Microscope (HR- TEM) imaging. HR-TEM micrographs revealed the presence of graphene in the residue. This result suggests that N-graphene could be present in benzene and nitrogen-rich icy clouds of Titan. The high masses observed by the Cassini plasma spectrometer in Titan’s atmosphere could then be attributed to the presence of N-graphene along with the more common tholins [7].</p> <p><strong>References</strong></p> <p>[1] Vinatier S. et al. (2018) <em>Icarus, 310,</em> 89.</p> <p>[2] Loison J. C. et al. (2019) <em>Icarus 329,</em> 55.</p> <p>[3] Strazzulla G. et al. (1991) <em>A&A, 241</em>, 310.</p> <p>[4] Callahan M. P. et al. (2013) <em>Icarus, 226</em>, 1201.</p> <p>[5] James R. et al. (2019) <em>RSC Adv. 9</em> (10), 5453.</p> <p>[6] Rahul K. K. et al. (2020) <em>Spectrochim. Acta A, 231, </em>117797.</p> <p>[7] Rahul K. K. et al. (2020) <em>arXiv:2008.10011</em>.</p>

The Observation of NBC Precipitates In Steels In The Nanometer Range Using A Field Emission Gun Scanning Electron Microscope

1997 ◽  
Vol 3 (S2) ◽  
pp. 1243-1244 ◽  
Author(s):  
Raynald Gauvin ◽  
Steve Yue
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Incident Electron Energy ◽  
Beam Diameter ◽  
Probe Diameter ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

The observation of microstructural features smaller than 300 nm is generally performed using Transmission Electron Microscopy (TEM) because conventional Scanning Electron Microscopes (SEM) do not have the resolution to image such small phases. Since the early 1990’s, a new generation of microscopes is now available on the market. These are the Field Emission Gun Scanning Electron Microscope with a virtual secondary electron detector. The field emission gun gives a higher brightness than those obtained using conventional electron filaments allowing enough electrons to be collected to operate the microscope with incident electron energy, E0, below 5 keV with probe diameter smaller than 5 nm. At 1 keV, the electron range is 60 nm in aluminum and 10 nm in iron (computed using the CASINO program). Since the electron beam diameter is smaller than 5 nm at 1 keV, the resolution of these microscopes becomes closer to that of TEM.

scholarly journals Six-Axis SEM Stage

1993 ◽  
Vol 1 (2) ◽  
pp. 8-8
Author(s):  
Ross Murosako
Keyword(s):  
General Purpose ◽  
Image Features ◽  
Signal Collection ◽  
Specimen Orientation ◽  
Electron Microscopes ◽  
Working Distance ◽  
Scanning Electron Microscopes ◽  
Five Axis ◽  
Picture Frame ◽  
Scanning Electron

The primary function of an SEM specimen stage is to optimize the orientation of the specimen to the signal detectors. The ease and precision with which the stage executes this function determine its utility to the microscopist. While the majority of scanning electron microscopes are equipped with general purpose five-axis specimen stages, a six-axis stage can significantly enhance specimen orientation. Specimen manipulation can be further simplified by incorporation of a six-axis hand controller that enables the microscopist to move the specimen intuitively as if the specimen were held directly in the hand.SEM manufacturers typically install general purpose five-axis specimen stages in their scanning electron microscopes. In addition to translation along the X and Y axes, these stages are capable of tilt (T), elevation (Z motion), and rotation (R). Tilt directs the specimen surface toward the secondary electron detector to optimize signal collection. Elevation adjusts the working distance while rotation orients specific image features within the picture frame.

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