Electron Beam Diffraction and Microscopy of Atomic-Scale Geometrical Structure

Nano-scaled thermoelectric materials attract significant interest due to their improved physical properties as compared to bulk materials. Well-shaped nanoparticles such as nano-bars and nano-cubes were observed in the known thermoelectric material PbTe. Their extended two-dimensional nano-layer arrangements form directly in situ through electron-beam treatment in the transmission electron microscope. The experiments show the atomistic depletion mechanism of the initial crystal and the recrystallization of PbTe nanoparticles out of the microparticles due to the local atomic-scale transport via the gas phase beyond a threshold current density of the beam.

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Hrem Of General And Twist Grain Boundaries

Microscopy and Microanalysis ◽

10.1017/s1431927600013866 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 108-109

Author(s):

K. L. Merkle ◽

L. J. Thompson

Keyword(s):

Thin Film ◽

Electron Beam ◽

Phase Space ◽

Grain Boundaries ◽

Scale Structure ◽

Zone Axis ◽

Low Energy ◽

Atomic Scale ◽

Dimensional Phase Space ◽

Scale Structures

The observation of atomic-scale structures of grain boundaries (GBs) via axial illumination HREM has been largely restricted to tilt GBs, due to the requirement that the electron beam be parallel to a low-index zone axis on both sides of the interface. This condition can be fulfilled for all tilt GBs with misorientation about a low-index direction. The information obtained through HREM studies in many materials has brought important insights concerning the atomic-scale structure of such boundaries. However, it is well known that tilt GBs occupy only an infinitesimally small fraction of the 5-dimensional phase space which describes the macroscopic geometry of all GBs. Therefore, although tilt GBs are very important due to their low energy, it would be usefulto also study twist GBs and general GBs that contain twist and tilt components.We have prepared thin-film Au samples by an epitaxy technique in which (01l) and (001) grains are grown side by side.

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Surface Structure of Sulfur Coated GaAs

MRS Proceedings ◽

10.1557/proc-163-1017 ◽

1989 ◽

Vol 163 ◽

Cited By ~ 1

Author(s):

Yoshihisa Fujisaki ◽

Shigeo Goto

Keyword(s):

Electron Beam ◽

Surface Structure ◽

Chemical Bond ◽

Photoelectron Spectroscopy ◽

Strong Dependence ◽

High Energy ◽

Chemical Bonds ◽

High Energy Electron ◽

X Ray ◽

Beam Diffraction

AbstractSurface structure of (NH4)2S treated GaAs. is investigated using PL (PhotoLuminescence), XPS (X-ray Photoelectron Spectroscopy) and RHEED (Reflection of High Energy Electron beam Diffraction). The data taken with these techniques show the strong dependence upon the crystal orientations coming from the stabilities of chemical bonds of Ga-S and As-S on GaAs crystals. The greater enhancement of PL intensity, the clearer RHEED patterns and the smaller amount of oxides on (111)A than (111)B implies the realization of a more stable structure composed mainly of the Ga-S chemical bond.

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Atomic Scale Study of Cosi/Si (111) and CoSi2/Si (111) Interfaces

MRS Proceedings ◽

10.1557/proc-159-147 ◽

1989 ◽

Vol 159 ◽

Cited By ~ 5

Author(s):

A. Catana ◽

M. Heintze ◽

P.E. Schmid ◽

P. Stadelmann

Keyword(s):

Electron Microscopy ◽

Electron Beam ◽

High Resolution ◽

Orientation Relationship ◽

Cross Sections ◽

High Resolution Electron Microscopy ◽

Atomic Scale ◽

Type B ◽

Initial Stage ◽

Resolution Electron

ABSTRACTHigh Resolution Electron Microscopy (HREM) was used to study microstructural changes related to the CoSi/Si-CoSi/CoSi2/Si-CoSi2/Si transformations. CoSi is found to grow epitaxially on Si with [111]Si // [111]CoSi and < 110 >Si // < 112 >CoSi. Two CoSi non-equivalent orientations (rotated by 180° around the substrate normal) can occur in this plane. They can be clearly distinguished by HRTEM on cross-sections ( electron beam along [110]Si). At about 500°C CoSi transforms to CoSi2. Experimental results show that the type B orientation relationship satisfying [110]Si // [112]CoSi is preserved after the initial stage of CoSi2 formation. At this stage an epitaxial CoSi/CoSi2/Si(111) system is obtained. The atomic scale investigation of the CoSi2/Si interface shows that a 7-fold coordination of the cobalt atoms is observed in both type A and type B epitaxies.

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Atomic-scale observation of pressure-dependent reduction dynamics of W18O49 nanowires using environmental TEM

Physical Chemistry Chemical Physics ◽

10.1039/c7cp03071a ◽

2017 ◽

Vol 19 (25) ◽

pp. 16307-16311

Author(s):

Zhengfei Zhang ◽

Liping Sheng ◽

Lu Chen ◽

Ze Zhang ◽

Yong Wang

Keyword(s):

Electron Beam ◽

Oxygen Pressure ◽

Electron Beam Irradiation ◽

Atomic Scale ◽

Beam Irradiation ◽

Environmental Tem

The oxygen pressure dependent reduction of W18O49 nanowires was observed by in situ TEM through electron beam irradiation.

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Atomic-Scale Electron-Beam Sculpting of Near-Defect-Free Graphene Nanostructures

Nano Letters ◽

10.1021/nl200369r ◽

2011 ◽

Vol 11 (6) ◽

pp. 2247-2250 ◽

Cited By ~ 193

Author(s):

Bo Song ◽

Grégory F. Schneider ◽

Qiang Xu ◽

Grégory Pandraud ◽

Cees Dekker ◽

...

Keyword(s):

Electron Beam ◽

Atomic Scale ◽

Free Graphene ◽

Graphene Nanostructures

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Probing the Dynamics of Topologically Protected Charged Ferroelectric Domain Walls with the Electron Beam at the Atomic Scale

Microscopy and Microanalysis ◽

10.1017/s1431927620023594 ◽

2020 ◽

Vol 26 (S2) ◽

pp. 3030-3032

Author(s):

Michele Conroy ◽

Kalani Moore ◽

Eoghan O'Connell ◽

Lewys Jones ◽

Clive Downing ◽

...

Keyword(s):

Electron Beam ◽

Domain Walls ◽

Ferroelectric Domain ◽

Atomic Scale

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Quantitative Determination of Bi Segregation at Grain Boundaries in Cu Bicrystals

Microscopy and Microanalysis ◽

10.1017/s1431927600009569 ◽

1997 ◽

Vol 3 (S2) ◽

pp. 535-536

Author(s):

U. Alber ◽

H. Müllejans ◽

M. Rühle

Keyword(s):

Electron Beam ◽

Grain Boundaries ◽

Primary Electron ◽

Atomic Scale ◽

Beam Diameter ◽

Primary Electron Beam ◽

Impurity Segregation ◽

A Value ◽

Bi Segregation ◽

Beam Broadening

Impurity segregation at grain boundaries (GB) can be detected by EDS in a dedicated STEM. Quantification of the segregation requires not only quantification of the spectra but also consideration of the geometry of the experiment. Our aim was to obtain a value which characterises only the segregation of the impurity and is independent of experimental parameters. The problem is that the specimen composition at the GB is extremely inhomogeneous on an atomic scale in the case of Bi segregation at GBs in Cu. The analysed volume which is defined by the irradiated area and the beam broadening of the primary electron beam inside the specimen contains the interfacial plane as well as neighbouring bulk Cu. One approach is to put the focussed primary electron beam on the interface which is aligned edge on and acquire a spectrum. Both the primary beam diameter and the beam broadening inside the specimen have to be known.

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Observation and Measurement of Atomic Scale Imperfections in Materials Using CBED+EBI/H

MRS Proceedings ◽

10.1557/proc-332-231 ◽

1994 ◽

Vol 332 ◽

Cited By ~ 2

Author(s):

Rodney A. Herring ◽

John E. Bonevich ◽

Takayoshi Tanji ◽

Akira Tonomura

Keyword(s):

Electron Beam ◽

Phase Change ◽

Heavy Ion ◽

Atomic Scale ◽

New Method ◽

Standard Methods ◽

Beam Electron ◽

Defect Clusters ◽

Diffraction Angle ◽

Convergent Beam

ABSTRACTA new method of electron interferometry/holography (CBED+EBI/H) has been realized which produces interference between convergent beam electron diffracted beams. An electron biprism placed between the diffracted beams compensates for their diffraction angle by an induced potential. When overlaid the diffracted beams interfere to produce an interferogram. Holography is possible due to coherency of the electron beam. Reconstruction of the hologram by standard methods enables the phase change around the defects to be measured. These methods are very easy to apply and examples are given for small defects and defect clusters in heavy-ion implanted Si.

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Electron Beam Induced Nanometre Hole Formation and Surface Modification in Al, Si And MgO

MRS Proceedings ◽

10.1557/proc-157-323 ◽

1989 ◽

Vol 157 ◽

Cited By ~ 4

Author(s):

Tim J. Bullough ◽

C. J. Humphreys ◽

R. W. Devenish

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Transmission Electron Microscope ◽

Electron Probe ◽

High Current Density ◽

Rapid Development ◽

Atomic Scale ◽

Exit Surface ◽

Transmission Electron ◽

Stationary Electron

ABSTRACTA wide variety of materials which are normally undamaged when exposed to a lOOkeV electron beam in a conventional transmission electron microscope can be modified on a nanometre scale by the high current density electron probe in a dedicated scanning transmission electron microscope (STEM). A stationary 100keV STEM electron probe can produce holes typically l-5nm diameter through crystalline Al, Si and MgO tens of nanometres in thickness, while a scanned electron beam can smooth surfaces on an atomic scale.In Al the stationary electron probe in the STEM produces a row of facetted voids along the irradiated volume. The voids grow initially inwards from the electron exit surface, with each void typically 4nm in diameter and 12-24nm in length, separated by equal distances from one another. In contrast, continuous holes 1.2-1.6nm diameter form at the electron exit surface of Si when exposed to the focused electron beam. However, these holes form only at specific randomly distributed points separated from one another by 2-4nm over the surface of crystalline specimens of both n- and p-doped <001> and <111> Si.Square cross-section holes with widths of about lnm can be formed by the stationary electron probe in MgO crystals. Rastering the probe over a restricted area of MgO initially results in the rapid development of surface islands and channels which are subsequently removed to leave an atomically smooth surface.

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