Improvement of amplitude-divided electron holography

1993 ◽  
Vol 51 ◽  
pp. 1220-1221
Author(s):  
Q. Ru ◽  
J. Endo ◽  
A. Tonomura
Keyword(s):  
Lattice Spacing ◽  
Gold Film ◽  
Carbon Film ◽  
Electron Holography ◽  
Electron Optics ◽  
Transmission Electron ◽  
Crystal Film ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
Electron Microscopes

Compared with the wavefront-divided electron holography obtained by an electron biprism, the amplitude-divided one proposed by Matteucci et al. has some essential advantages: less necessary coherency, wide interference area and available to most of transmission electron microscopes. In order to confirm and achieve these advantages in practical use, we introduce some improvements in both hologram formation and reconstruction steps. Two electron-optical setups and experimental results are presented for small objects (<1 μm) and much large objects (>1 μm), respectively.The electron-optics for taking the holograms of small objects is illustrated in Figure 1. A single crystal thin film (gold film of 0.2nm lattice spacing is used in our experiment) is placed on the objects (latex particles of 120 nm on a thin carbon film are used here) with a certain gap. In fact, the gap is spontaneously made by the microgrids of the specimen film and the crystal film.

A high-resolution fraunhofer in-line electron holography

1993 ◽  
Vol 51 ◽  
pp. 1222-1223
Author(s):  
Takao Matsumoto ◽  
Takayoshi Tanji ◽  
Akira Tonomura
Keyword(s):  
High Resolution ◽  
Carbon Film ◽  
Electron Holography ◽  
Phase Object ◽  
Strong Phase ◽  
The Core ◽  
Weak Phase ◽  
Transmission Electron ◽  
Thin Carbon ◽  
Thin Carbon Film

In-line holography is advantageous in terms of contrast in imaging weak phase objects. However, most of the recent articles on electron holography had an off-axis configuration employing an electron biprism and were applied successfully only to objects with a rather strong phase shift such as magnetic flux and thin crystals. When it comes to the observation of considerably weak phase object, the off-axis method fails. We applied Fraunhofer in-line electron holography to observe an undecagold cluster, the core of which has a diameter of 0.82 nm, and obtained a high resolution image with high contrast that has been obtained neither by off-axis electron holography nor by conventional transmission electron microscopy.A Hitachi HF-2000 electron microscope equipped with a 200-kV cold field emission gun was used during the experiment. The specimen, Monoamino-Undecagold (NanoProbes, Inc., Stony Brook, N.Y.), was prepared in a highly dispersive form on a thin carbon film supported by a thick holey carbon film.

Application of electron holography to material science studies on magnetic domain states of small particles

1993 ◽  
Vol 51 ◽  
pp. 1028-1029
Author(s):  
T. Hirayama ◽  
Q. Ru ◽  
T. Tanji ◽  
A. Tonomura
Keyword(s):  
Magnetic Field ◽  
Material Science ◽  
Science Studies ◽  
Phase Distribution ◽  
Carbon Film ◽  
Objective Lens ◽  
Electron Holography ◽  
Transform Method ◽  
Transmission Electron ◽  
Thin Carbon

The observation of small magnetic materials is one of the most important applications of electron holography to material science, because interferometry by means of electron holography can directly visualize magnetic flux lines in a very small area. To observe magnetic structures by transmission electron microscopy it is important to control the magnetic field applied to the specimen in order to prevent it from changing its magnetic state. The easiest method is tuming off the objective lens current and focusing with the first intermediate lens. The other method is using a low magnetic-field lens, where the specimen is set above the lens gap.Figure 1 shows an interference micrograph of an isolated particle of barium ferrite on a thin carbon film observed from approximately [111]. A hologram of this particle was recorded by the transmission electron microscope, Hitachi HF-2000, equipped with an electron biprism. The phase distribution of the object electron wave was reconstructed digitally by the Fourier transform method and converted to the interference micrograph Fig 1.

Hydrated form of some clay minerals observed using a film sealed environmental cell

1978 ◽  
Vol 36 (1) ◽  
pp. 72-73
Author(s):  
N. Kohyama ◽  
K. Fukushima ◽  
A. Fukami
Keyword(s):  
Clay Minerals ◽  
Morphological Changes ◽  
Carbon Film ◽  
Electron Microscopic Observation ◽  
Adsorbed Water ◽  
Electron Microscopic ◽  
Hydrated Form ◽  
Thin Carbon ◽  
Environmental Cell ◽  
Thin Carbon Film

Since the interlayer or adsorbed water of some clay minerals are quite easily dehydrated in dried air, in vacuum, or at moderate temperatures even in the atmosphere, the hydrated forms have not been observed by a conventional electron microscope(TEM). Recently, specific specimen chambers, “environmental cells(E.C.),” have been developed and confirmed to be effective for electron microscopic observation of wet specimen without dehydration. we observed hydrated forms of some clay minerals and their morphological changes by dehydration using a TEM equipped with an E.C..The E.C., equipped with a single hole copper-microgrid sealed by thin carbon-film, attaches to a TEM(JEM 7A) with an accelerating voltage 100KV and both gas pressure (from 760 Torr to vacuum) and relative humidity can be controlled. The samples collected from various localities in Japan were; tubular halloysite (l0Å) from Gumma Prefecture, sperical halloysite (l0Å) from Tochigi Pref., and intermediate halloysite containing both tubular and spherical types from Fukushima Pref..

Alkaline Dissociation Products of Lumbricus Terrestris Hemoglobin Viewed with the STEM

1981 ◽  
Vol 39 ◽  
pp. 434-435
Author(s):  
O. H. Kapp ◽  
M. Ohtsuki ◽  
N. Robin ◽  
S. N. Vinogradov ◽  
A. V. Crewe
Keyword(s):  
Carbon Film ◽  
Lumbricus Terrestris ◽  
Uranyl Acetate ◽  
Acetate Solution ◽  
Oxygen Carriers ◽  
Complex Molecules ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
Multiple Copies ◽  
Hill Coefficients

Annelid extracellular hemoglobins are among the largest known proteins (M.W = 3.9 x 106), and together with the hemocyanins are the largest known oxygen carriers. They display oxygen affinities generally higher than those o vertebrate hemoglobins with Hill coefficients ranging from slightly higher than unity to values as high as 5-6. These complex molecules are composed of multiple copies of as many as six different polypeptides and posse: approximately 150 hemes per molecule.The samples were diluted to 100-200 μg/ml with distilled water just before application to a thin carbon film (∽15 Å thick). One percent (w/v) uranyl acetate solution was used for negative staining for 2 minutes and dried in air. The specimens were examined with the high resolution STEM. Their general appearance is that of a hexagonal bilayer (Fig. 1), each layer consisting of six spheroidal subunits. The corner to corner hexagonal dimensic is approximately 300 Å and the bilayer thickness approximately 200 Å.

scholarly journals Modern Microscopy on the Light Side: TEM in the Trenches

1993 ◽  
Vol 1 (4) ◽  
pp. 6-10
Author(s):  
Stephen E. Rice
Keyword(s):  
Science Fiction ◽  
Great Promise ◽  
Electron Holography ◽  
Imaging Device ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Light Side ◽  
Convergent Beam ◽  
Made In

Great strides have been made in the last decade in high resolution transmission electron microscopes (TEMs) which can also provide elemental information via energy dispersive X-ray analysis (EDX) or energy loss spectroscopy (EELS), and proponents of various TEM techniques make bold claims. Convergent beam elecjron diffraction and microdifff action shine as techniques for defect structure analysis and means for solving crystal structures. The spectroscopies can now be used to map chemical state information at a level which until recently might be encountered in science fiction. As a pure imaging device, electron holography holds great promise for providing Ehe ultimate (would you believe 0.1Å?) imaging resolution. Although conventional TEMs will never approach this, it appears that we are learning more and more about less and less, until we will soon know everything there is to know about nothing.

Thin carbon film deposition using energetic ions of a dense plasma focus

1997 ◽  
Vol 226 (3-4) ◽  
pp. 212-216 ◽  
Author(s):  
Chhaya R. Kant ◽  
M.P. Srivastava ◽  
R.S. Rawat
Keyword(s):  
Plasma Focus ◽  
Dense Plasma ◽  
Carbon Film ◽  
Film Deposition ◽  
Dense Plasma Focus ◽  
Energetic Ions ◽  
Thin Carbon ◽  
Thin Carbon Film

Effects of Amorphous Carbon Films on the Performance of Porous Silicon Electroluminescence

2002 ◽  
Vol 737 ◽  
Author(s):  
Bernard Gelloz ◽  
Nobuyoshi Koshida
Keyword(s):  
Porous Silicon ◽  
Amorphous Carbon ◽  
Chemical Stability ◽  
Indium Tin Oxide ◽  
Carbon Film ◽  
Carbon Films ◽  
Positive Effects ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
The Stability

ABSTRACTEfficient electroluminescence (EL) is obtained at low operating voltages (<3 V) from n+-type silicon- electrochemically oxidized thin nanocrystalline porous silicon (PS)-amorphous carbon-Indium tin oxide (ITO) junctions. The effects of a few nanometer thick amorphous carbon film between PS and ITO on the EL characteristics have been investigated. The carbon film enhances the stability. The EL efficiency is improved due to a reduction of current density and an increase in EL intensity. In addition, the reproducibility from device to device is very much improved by the carbon film. The enhancement in stability should originate from the capping of PS by the carbon film and the high chemical stability of carbon and Si-C bonds, which should prevent PS oxidation. The carbon film acts as an efficient buffer layer between PS and ITO, resulting in enhanced mechanical, electrical and chemical stability of the top contact and providing high reproducibility. The thin carbon film has only positive effects on all the EL characteristics. This is a very important step towards application.

scholarly journals Atomically resolved tomographic reconstruction of nanoparticles from Single Projection: influence of amorphous carbon support

2020 ◽  
Author(s):  
Pritam Banerjee ◽  
Chiranjit Roy ◽  
Subhra Kanti De ◽  
Antonio J. Santos ◽  
Francisco M. Morales ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Tomographic Reconstruction ◽  
Carbon Film ◽  
Carbon Support ◽  
Atomic Scale ◽  
Structure Property ◽  
Transmission Electron ◽  
Wide Range ◽  
Correlation Information ◽  
Electron Microscopes

Abstract Nanoparticles have a wide range of applications due to their unique geometry and arrangement of atoms. For a precise structure-property correlation, information regarding atomically resolved 3D structures of nanoparticles is utmost beneficial. Though modern aberration-corrected transmission electron microscopes can resolve atoms with sub-angstrom resolution, an atomic-scale 3D reconstruction of nanoparticle is a challenge using tilt series tomography due to high radiation damage. Instead, inline 3D holography based tomographic reconstructions from single projection registered at low electron doses are more suitable for defining atoms dispositions at nanostructures. Nanoparticles are generally supported on amorphous carbon film for TEM experiments. However, neglecting the influence of carbon film on the tomographic reconstruction of the nanoparticle may lead to ambiguity. In order to address this issue, the effect of amorphous carbon support was quantitatively studied using simulations and experiments.

scholarly journals Interpretational challenges related to studies of chalk particle surfaces in scanning and transmission electron microscopy

2018 ◽  
Vol 66 ◽  
pp. 151-165
Author(s):  
Morten Leth Hjuler ◽  
Vidar Folke Hansen ◽  
Ida Lykke Fabricius
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Carbon Film ◽  
Burial Depth ◽  
High Electron ◽  
Ion Milling ◽  
Transmission Electron ◽  
Thin Carbon ◽  
Acceleration Voltage

Scanning and transmission electron microscopy (SEM and TEM) are capable of characterising the morphology and structure of sub-micron size substances attached to chalk particle surfaces. Some characteristics, however, may originate from sample preparation or reflect interaction between sample and the electron beam. Misinterpretation of surface features may lead to wrong conclusions regarding grain surface properties and cementation level and thus to erroneous characterisation of hydrocarbon reservoirs with respect to e.g. wettability, mechanical strength and maximum burial depth. In SEM, conductive coatings may mask surface details or generate artificial ornamentations, and carbon adhesive discs may cause the chalk surface to be covered with a thin carbon film. Electron beam acceleration voltage controls the degree of detail revealed by the electron beam, but in SEM a high electron beam acceleration voltage may provoke bending or curling of ultrathin particles. Recent organic filaments may be confused with clay flakes, and authigenic non-carbonate minerals may have formed in the pore fluid and settled during fluid removal. In TEM, the high acceleration voltage may cause beam damage to calcite and transform the outermost atomic layers into Ca oxide. Thin graphite membranes observed by TEM may be contamination from the carbon film supporting the sample, and overlapping chalk particles in samples formed by drying of a suspension may give the impression of being cemented together. In TEM residual adhesive from the ion-milling process can be confused with cementation features.

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