Aberration-corrected HRTEM of the Incommensurate Misfit Layer Compound (PbS)1.14NbS2

2007 ◽  
Vol 1026 ◽  
Author(s):  
Magnus Garbrecht ◽  
Erdmann Spiecker ◽  
Wolfgang Jäger ◽  
Karsten Tillmann
Keyword(s):  
Spherical Aberration ◽  
Atomic Scale ◽  
Transition Metal Dichalcogenide ◽  
Layer Compound ◽  
X Ray ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Interesting Class ◽  
Electron Microscopes ◽  
Set Up

AbstractThe development of tunable spherical aberration (Cs) imaging correctors for medium-voltage transmission electron microscopes (TEM) offers new opportunities for atomic-scale in-vestigations of materials. A very interesting class of microstructures regarding a variety of dif-ferent physical properties are the transition metal dichalcogenide misfit layer compounds exhibit-ing a high density of incommensurate interfaces due to their stacked nature. In the present study, the benefits coming along with the set-up of negative CS imaging (NCSI) conditions (in TEM) are demonstrated by means of different examples regarding local inhomogeneities in (PbS)1.14NbS2 crystals that can not be dissected in such detail by averaging x-ray techniques.

The Electron Microscope in Earth Sciences

1978 ◽  
Vol 36 (3) ◽  
pp. 404-419
Author(s):  
H.R. Wenk
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Atomic Scale ◽  
Rock Deformation ◽  
Environmental Geology ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes

Over the last ten years the electron microscope has become well-established in mineralogical research and what used to be an exotic instrument has found its way into several geology departments. The rapidly growing literature on electron microscopy in mineralogy has recently been summarized (Wenk et al., 1976) and there is not much point in systematically reviewing progress of the last two years. Philosophy and techniques remained largely the same except that there is more emphasis on high resolution, and energy dispersive X-ray detectors have become standard attachments of electron microscopes. Instead I would like to use some examples studied at the Geology Department at Berkeley during the last few months to illustrate a variety of applications in materials which could not be investigated with conventional techniques such as light microscopy, standard chemical analyses and X-ray diffraction. Geology is a broad science which ranges from the study of crystal structures on the atomic scale to processes taking place during mountain building on the scale of the size of continents. The transmission electron microscope has been used in such diverse fields as crystallography, petrology, rock deformation, stratigraphy and environmental geology.

An Ultra-High-Resolution Objective Lens for a 200-kV TEM

1990 ◽  
Vol 48 (1) ◽  
pp. 132-133
Author(s):  
J.G. Bakker ◽  
P.E.S. Asselbergs
Keyword(s):  
High Resolution ◽  
Structural Information ◽  
Spherical Aberration ◽  
Atomic Scale ◽  
Objective Lens ◽  
High Resolution Imaging ◽  
X Ray ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Resolution Imaging

High resolution TEM imaging has been well established as superb technique for obtaining structural information about materials on an atomic scale. Trends in equipment for high resolution imaging have progressed to the stage where point resolutions below 2 Å can be obtained at 200 kV. This paper describes such a new objective lens for the Philips CM20 Transmission Electron Microscope.In designing a new objective lens, several parameters have to be taken into account. Not only should the coefficient of spherical aberration of the objective lens be minimised, the lens should also allow considerable tilting of the specimen in two directions. The lens should be compatible with X-ray analysis. And last but not least, the design of lens must ensure that the heat transfer of the lens to the specimen environment is minimised.

Removing Substrate Background in TEM Microanalysis

1974 ◽  
Vol 32 ◽  
pp. 568-569
Author(s):  
John C. Russ ◽  
Nicholas C. Barbi
Keyword(s):  
Electrical Conductivity ◽  
Rapid Growth ◽  
Organic Film ◽  
Absolute Concentration ◽  
Background Signal ◽  
X Ray ◽  
Elemental Concentrations ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
The Continuum

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.

Transmission electron microscope studies in special ceramics

1978 ◽  
Vol 36 (1) ◽  
pp. 268-269
Author(s):  
A. Zangvil ◽  
L.J. Gauckler ◽  
G. Schneider ◽  
M. Rühle
Keyword(s):  
Phase Diagrams ◽  
Crystal Structures ◽  
Thin Foil ◽  
Limited Extent ◽  
Complex Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Lattice Resolution

The use of high temperature special ceramics which are usually complex materials based on oxides, nitrides, carbides and borides of silicon and aluminum, is critically dependent on their thermomechanical and other physical properties. The investigations of the phase diagrams, crystal structures and microstructural features are essential for better understanding of the macro-properties. Phase diagrams and crystal structures have been studied mainly by X-ray diffraction (XRD). Transmission electron microscopy (TEM) has contributed to this field to a very limited extent; it has been used more extensively in the study of microstructure, phase transformations and lattice defects. Often only TEM can give solutions to numerous problems in the above fields, since the various phases exist in extremely fine grains and subgrain structures; single crystals of appreciable size are often not available. Examples with some of our experimental results from two multicomponent systems are presented here. The standard ion thinning technique was used for the preparation of thin foil samples, which were then investigated with JEOL 200A and Siemens ELMISKOP 102 (for the lattice resolution work) electron microscopes.

Current Status of Solid-State X-Ray Systems

1985 ◽  
Vol 43 ◽  
pp. 158-161
Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis
Keyword(s):  
Solid State ◽  
Electric Fields ◽  
Spectral Lines ◽  
Current Status ◽  
Mobile Charge ◽  
Electron Hole ◽  
X Ray ◽  
Sensing Systems ◽  
Transmission Electron ◽  
Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

Limits for high-resolution electron microscopy of inorganic materials?

1987 ◽  
Vol 45 ◽  
pp. 4-5
Author(s):  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Spherical Aberration ◽  
High Resolution Electron Microscopy ◽  
Inorganic Materials ◽  
Atomic Scale ◽  
Resolution Limit ◽  
Contrast Transfer Function ◽  
Existing Problems ◽  
Resolution Electron ◽  
Electron Microscopes

The era of atomic-resolution electron microscopy has finally arrived. In virtually all inorganic materials, including oxides, metals, semiconductors and ceramics, it is possible to image individual atomic columns in low-index zone-axis projections. A whole host of important materials’ problems involving defects and departures from nonstoichiometry on the atomic scale are waiting to be tackled by the new generation of intermediate voltage (300-400keV) electron microscopes. In this review, some existing problems and limitations associated with imaging inorganic materials are briefly discussed. The more immediate problems encountered with organic and biological materials are considered elsewhere.Microscope resolution. It is less than a decade since the state-of-the-art, commercially available TEM was a 200kV instrument with a spherical aberration coefficient of 1.2mm, and an interpretable resolution limit (ie. first zero crossover of the contrast transfer function) of 2.5A.

scholarly journals Chemical Quantification of Atomic-Scale EDS Maps under Thin Specimen Conditions

2014 ◽  
Vol 20 (6) ◽  
pp. 1782-1790 ◽  
Author(s):  
Ping Lu ◽  
Eric Romero ◽  
Shinbuhm Lee ◽  
Judith L. MacManus-Driscoll ◽  
Quanxi Jia
Keyword(s):  
Atomic Scale ◽  
Specimen Thickness ◽  
Peak Width ◽  
Thin Specimen ◽  
Gaussian Peak ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Relationship ◽  
Chemical Quantification

AbstractWe report our effort to quantify atomic-scale chemical maps obtained by collecting energy-dispersive X-ray spectra (EDS) using scanning transmission electron microscopy (STEM) (STEM-EDS). With thin specimen conditions and localized EDS scattering potential, the X-ray counts from atomic columns can be properly counted by fitting Gaussian peaks at the atomic columns, and can then be used for site-by-site chemical quantification. The effects of specimen thickness and X-ray energy on the Gaussian peak width are investigated using SrTiO3 (STO) as a model specimen. The relationship between the peak width and spatial resolution of an EDS map is also studied. Furthermore, the method developed by this work is applied to study cation occupancy in a Sm-doped STO thin film and antiphase boundaries (APBs) present within the STO film. We find that Sm atoms occupy both Sr and Ti sites but preferably the Sr sites, and Sm atoms are relatively depleted at the APBs likely owing to the effect of strain.

scholarly journals FEI Tecnai G2 F20

2016 ◽  
Vol 2 ◽  
Author(s):  
Martina Luysberg ◽  
Marc Heggen ◽  
Karsten Tillmann
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Dark Field ◽  
Conventional Imaging ◽  
Electron Loss ◽  
High Angle ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Set Up ◽  
Elemental Maps

The FEI Titan Tecnai G2 F20 is a versatile transmission electron microscope which is equipped with a Gatan Tridiem 863P post column image filter (GIF) and a high angle energy dispersive X-ray (EDX) detector. This set up allows for a variety of experiments such as conventional imaging and diffraction, recording of bright- and dark-field scanning transmission electron microscopy (STEM) images, or acquiring elemental maps extracted from energy electron loss spectra (EELS) or EDX signals.

scholarly journals FEI Titan 80-300 TEM

2016 ◽  
Vol 2 ◽  
Author(s):  
Andreas Thust ◽  
Juri Barthel ◽  
Karsten Tillmann
Keyword(s):  
Electron Microscope ◽  
Solid State ◽  
Spherical Aberration ◽  
Atomic Scale ◽  
Atomic Resolution ◽  
Lens System ◽  
Stage Design ◽  
Precise Positioning ◽  
Transmission Electron ◽  
Wide Range

The FEI Titan 80-300 TEM is a high-resolution transmission electron microscope equipped with a field emission gun and a corrector for the spherical aberration (<em>C</em><sub>S</sub>) of the imaging lens system. The instrument is designed for the investigation of a wide range of solid state phenomena taking place on the atomic scale, which requires true atomic resolution capabilities. Under optimum optical settings of the image <em>C</em><sub>S</sub>-corrector (CEOS CETCOR) the point-resolution is extended up to the information limit of well below 100 pm with 200 keV and 300 keV electrons. A special piezo-stage design allows ultra-precise positioning of the specimen in all 3 dimensions. Digital images are acquired with a Gatan 2k x 2k slow-scan charged coupled device camera.

Doping and Characterisation of Nanocrystalline Materials

2007 ◽  
Vol 128 ◽  
pp. 61-72
Author(s):  
Th. Wichert ◽  
Z. Guan
Keyword(s):  
Nanocrystalline Materials ◽  
Local Information ◽  
Atomic Scale ◽  
Radioactive Isotopes ◽  
Correlation Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Significant Process ◽  
X Ray Absorption

The synthesis behaviour and characterisation of nanocrystalline materials is presented. The materials synthesised are ZnO and InP doped with shallow donors and acceptors, respectively. Characterisation was performed with radioactive isotopes using the perturbed γγ angular correlation technique (PAC), thereby yielding local information on an atomic scale. The characterisation was supplemented by X-ray diffraction, transmission electron microscopy, UV/VIS absorption spectroscopy, photoluminescence spectroscopy, and extended X-ray absorption fine structure spectroscopy. It was shown that the successful incorporation of dopants in nanocrystalline ZnO and InP requires annealing at temperatures at which the growth of the nanocrystals in the sample becomes a significant process.

Sign in / Sign up

Export Citation Format

Share Document