High-resolution imaging of the (111) Ag/Ni interface

Computer simulations of Ag/Ni interfaces using embedded atom potentials have predicted that the interfacial energy of the (111) Ag/Ni interface is lowest. However, the semi-coherent interface configuration implied by these calculations has not been confirmed by experimental observation. It is well known that in heterophase systems with small misfit, the misfit is accommodated by misfit dislocations at the interface, forming a semi-coherent interface. However, it is not clear whether or not and to what degree misfit localization will occur at the interfaces with as large a misfit as 14% (Ag/Ni interface). The purpose of this investigation was to examine the atomic structure of the (111) Ag/Ni interface by high-resolution electron microscopy (HREM) and to compare the result to calculated images based on relaxed and rigid models.Metal-metal composite thin films of Ni particles in a Ag matrix were produced by epitaxial growth on (110) NaCl substrates using a special technique described in detail elsewhere. HREM observations were performed using H-9000 at a Northwestern University operated at 300 kV. The images were obtained near optimum defocus without objective aperture. All image simulations were carried out using the multislice method with EMS program package.

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High-resolution electron microscopy of metal/metal and metal/metal-oxide interfaces in the Ag/Ni and Au/Ni systems

Journal of Materials Research ◽

10.1557/jmr.1990.1995 ◽

1990 ◽

Vol 5 (9) ◽

pp. 1995-2003 ◽

Cited By ~ 42

Author(s):

Y. Gao ◽

Karl L. Merkle

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Metal Oxide ◽

High Resolution Electron Microscopy ◽

Misfit Dislocations ◽

Oxide Systems ◽

Lattice Statics ◽

Embedded Atom ◽

Resolution Electron ◽

Metal Metal

The atomic structures of heterophase interfaces with large misfits (>14% in Ag/Ni and Au/Ni) and with small misfits (∼2% in Ag/NiO and Au/NiO) have been studied by high-resolution electron microscopy (HREM). It is found that all interfaces are strongly faceted on (111) planes. This indicates that (111) interfaces have the lowest interfacial energy in both metal/metal and metal/metal-oxide systems. For the metal interfaces, this also agrees with determinations of interfacial energies by lattice statics calculations. The large misfit of Ag/Ni and Au/Ni interfaces is accommodated by misfit dislocations. Observations of misfit localization by HREM are in good agreement with images derived from computer simulation, based on relaxed structures, obtained in embedded atom calculations. All misfit dislocations at the Ag/Ni and Au/Ni interfaces lie exactly in the plane of the interfaces, while the dislocations at Ag/NiO and Au/NiO interfaces reside at a stand-off distance, 3 to 4 (111)Ag or (111)Au interplanar spacings from the interfaces.

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Atomic Structure of Ag/Ni Interfaces

MRS Proceedings ◽

10.1557/proc-183-39 ◽

1990 ◽

Vol 183 ◽

Cited By ~ 7

Author(s):

Y. Gao ◽

K. L. Merkle

Keyword(s):

Atomic Structure ◽

High Resolution Electron Microscopy ◽

Lattice Parameter ◽

Special Technique ◽

Misfit Dislocations ◽

Lattice Statics ◽

Embedded Atom ◽

Resolution Electron ◽

Small Lattice ◽

Model Structures

AbstractWhile in heterophase systems of small lattice parameter differences, misfit dislocations are often formed at the interface, it is not known, whether and in which form, misfit localization occurs when the misfit is very large. The atomic structure of Ag/Ni interfaces (misfit 14%) was studied by high-resolution electron microscopy (HREM). A special technique was developed to prepare interface specimens suitable for HREM observations.Lattice statics calculations, using embedded-atom potentials, were performed to determine the structure and energies of Ag/Ni interfaces. The lowest interfacial energy was found for the cube-on-cube orientation and (111) interfaces. This is in agreement with the experimental observation, that all interfaces are strongly faceted with (111)Ag/(111)Ni facets.Misfit localization was found by HREM and computer simulation. The HREM observations will be compared to images derived from image simulations, based on model structures obtained from embedded atom calculations.

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Alternative approaches to ultra-high resolution imaging

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087562 ◽

1991 ◽

Vol 49 ◽

pp. 650-651

Author(s):

J.M. Cowley

Keyword(s):

High Resolution ◽

High Voltage ◽

High Resolution Electron Microscopy ◽

Crystal Defects ◽

High Resolution Imaging ◽

General Applicability ◽

Resolution Electron ◽

Radiation Resistant ◽

Resolution Imaging ◽

Alternative Approaches

By extrapolation of past experience, it would seem that the future of ultra-high resolution electron microscopy rests with the advances of electron optical engineering that are improving the instrumental stability of high voltage microscopes to achieve the theoretical resolutions of 1Å or better at 1MeV or higher energies. While these high voltage instruments will undoubtedly produce valuable results on chosen specimens, their general applicability has been questioned on the basis of the excessive radiation damage effects which may significantly modify the detailed structures of crystal defects within even the most radiation resistant materials in a period of a few seconds. Other considerations such as those of cost and convenience of use add to the inducement to consider seriously the possibilities for alternative approaches to the achievement of comparable resolutions.

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Nano-probe x-ray analysis and high-resolution imaging on planar defects in high-pressure synthesized infinite-layer superconductor

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100171377 ◽

1994 ◽

Vol 52 ◽

pp. 728-729

Author(s):

Y. Y. Wang ◽

H. Zhang ◽

V. P. Dravid ◽

H. Zhang ◽

L. D. Marks ◽

...

Keyword(s):

High Pressure ◽

High Resolution ◽

Atomic Structure ◽

Emission Spectra ◽

High Resolution Electron Microscopy ◽

Planar Defects ◽

X Ray ◽

Infinite Layer ◽

Resolution Electron ◽

Resolution Imaging

Azuma et al. observed planar defects in a high pressure synthesized infinitelayer compound (i.e. ACuO2 (A=cation)), which exhibits superconductivity at ~110 K. It was proposed that the defects are cation deficient and that the superconductivity in this material is related to the planar defects. In this report, we present quantitative analysis of the planar defects utilizing nanometer probe xray microanalysis, high resolution electron microscopy, and image simulation to determine the chemical composition and atomic structure of the planar defects. We propose an atomic structure model for the planar defects.Infinite-layer samples with the nominal chemical formula, (Sr1-xCax)yCuO2 (x=0.3; y=0.9,1.0,1.1), were prepared using solid state synthesized low pressure forms of (Sr1-xCax)CuO2 with additions of CuO or (Sr1-xCax)2CuO3, followed by a high pressure treatment.Quantitative x-ray microanalysis, with a 1 nm probe, was performed using a cold field emission gun TEM (Hitachi HF-2000) equipped with an Oxford Pentafet thin-window x-ray detector. The probe was positioned on the planar defects, which has a 0.74 nm width, and x-ray emission spectra from the defects were compared with those obtained from vicinity regions.

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HIGH RESOLUTION ELECTRON MICROSCOPE STUDY OF CdTe-Cd0.6Mn0.4 Te SUPERLATTICES

MRS Proceedings ◽

10.1557/proc-56-235 ◽

1985 ◽

Vol 56 ◽

Cited By ~ 1

Author(s):

C. CHOI ◽

N. OTSUKA ◽

L. A. KOLODZIEJSKI ◽

R. L. GUNSHOR-a

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Phase Contrast ◽

Electron Microscope Study ◽

Lattice Mismatch ◽

Thick Layer ◽

High Resolution Electron Microscopy ◽

Misfit Dislocations ◽

Resolution Electron ◽

High Resolution Electron Microscope

AbstractStructures of CdTe-Cd0.6Mn0.4Te superlattices which are caused by the lattice mismatch between suterlattice layers have been studied by high resolution electron microscopy (HREM). In thin-layer superlattices, the crystal lattice in each layeris elastically distorted, resulting in the change of the crystal symmetry from cubic to rhombohedral. The presence of the small rhombohedral distrotion has been confirmed through a phase contrast effect in HREM images. In a thick-layer superlattice, the lattice mismatch is accommodated by dissociated misfit dislocations. Burgers vectors of partial misfit dislocations have been identified from the shift of lattice fringes in HREM images.

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Structure of twinned {113} defects in high-dose oxygen implanted silicon-on-insulator material

Journal of Materials Research ◽

10.1557/jmr.1991.0792 ◽

1991 ◽

Vol 6 (4) ◽

pp. 792-795 ◽

Cited By ~ 4

Author(s):

Supapan Visitserngtrakul ◽

Stephen J. Krause ◽

John C. Barry

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Oxide Layer ◽

High Resolution Electron Microscopy ◽

Silicon On Insulator ◽

High Dose ◽

Diamond Structure ◽

Bulk Silicon ◽

Coherent Interface ◽

Resolution Electron

Conventional and high resolution electron microscopy (HREM) were used to study the structure of {113} defects in high-dose oxygen implanted silicon. The defects are created with a density of 1011 cm−2 below the buried oxide layer in the substrate region. The HREM images of the {113} defects are similar to the ribbon-like defects in bulk silicon. It is proposed that there is a third possible structure of the defects, in addition to coesite and/or hexagonal structures. Portions of some defects exhibit the original cubic diamond structure which is twinned across {115} planes. The atomic model shows that the {115} interface is a coherent interface with alternating five- and seven-membered rings and no dangling bonds.

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High-resolution electron microscopy of epitaxial YBCO/Y2O3/YSZ on Si(001)

Journal of Materials Research ◽

10.1557/jmr.1993.2112 ◽

1993 ◽

Vol 8 (9) ◽

pp. 2112-2127 ◽

Cited By ~ 40

Author(s):

A. Bardal ◽

O. Eibl ◽

Th. Matthée ◽

G. Friedl ◽

J. Wecker

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Thick Layer ◽

Atomic Layer ◽

High Resolution Electron Microscopy ◽

Stacking Fault ◽

Buffer Layers ◽

Misfit Dislocations ◽

Resolution Electron ◽

Unit Cells

The microstructures of YBa2Cu3O7−δ (YBCO) thin films grown on Si with Y-stabilized ZrO2 (YSZ) and Y2O3 buffer layers were characterized by means of high-resolution electron microscopy. At the Si–YSZ interface, a 2.5 nm thick layer of regrown amorphous SiOx is present. The layer is interrupted by crystalline regions, typically 5 to 10 nm wide and 10 to 50 nm apart. Close to the crystalline regions, {111} defects are present in the Si substrate. The typical defect observed is an extrinsic stacking fault plus a perfect dislocation close to the stacking fault which terminates extra {111} planes in the upper part of the Si. These defects are probably formed by condensation of Si self-interstitials created during oxide regrowth. Precipitates are present in the Si close to the Si–YSZ interface and indicate that in-diffusion of Zr has occurred. The YSZ–Y2O3 interface is atomically sharp and essentially planar and contains no second phases. Perfect misfit dislocations with Burgers vector 1/2〈110〉 are present at this interface along with unrelaxed elastic misfit stresses. The Y2O3–YBCO interface is atomically sharp and planar, but contains steps. (001) stacking faults are present in the YBCO above these steps; the faults are, however, healed a few unit cells away from the interface. By HREM analysis of ultrathin specimen areas, the atomic layer of the YBCO closest to the Y2O3 was found to be a barium-oxygen layer.

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Twinning Structure of {113} Defects in High-Dose Oxygen Implanted Silicon-on-Insulator Material.

MRS Proceedings ◽

10.1557/proc-163-955 ◽

1989 ◽

Vol 163 ◽

Cited By ~ 1

Author(s):

S. Visitserngtrakul ◽

J. Barry ◽

S. Krause

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Oxide Layer ◽

High Resolution Electron Microscopy ◽

Silicon On Insulator ◽

High Dose ◽

Diamond Structure ◽

Bulk Silicon ◽

Coherent Interface ◽

Resolution Electron

AbstractConventional and high resolution electron microscopy (HREM) were used to study the structure of the {113} defects in high-dose oxygen implanted silicon. The defects are created with a density of 1011 cm-2 below the buried oxide layer in the substrate region. The {113} defects are similar to the ribbon-like defects in bulk silicon. Our HREM observations show that two crystalline phases are present in the defect. Portions of the defects exhibit the original cubic diamond structure which is twinned across {115} planes. The atomic model shows that the {115} interface is a coherent interface with alternating five- and seven-membered rings and no dangling bonds.

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Direct structure analysis of advanced nanomaterials by high-resolution electron microscopy

Nanotechnology Reviews ◽

10.1515/ntrev-2012-0018 ◽

2012 ◽

Vol 1 (5) ◽

pp. 389-425 ◽

Cited By ~ 10

Author(s):

Takeo Oku

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Nanostructured Materials ◽

Structure Analysis ◽

Incident Beam ◽

High Resolution Electron Microscopy ◽

Structure Model ◽

Resolution Electron ◽

Correction Technique ◽

Resolution Imaging

AbstractHigh-resolution electron microscopy (HREM) analysis has contributed to the direct structure analysis of advanced nanostructured materials, of which the properties of these materials are strongly dependent on the atomic arrangements. In the present article, the direct structure analysis of nanostructured materials such as boride and oxide materials was described and the high-resolution imaging methods were applied to boron nitride nanomaterials such as nanotubes and nanoparticles. An aberration correction technique is also expected as an advanced nanostructure analysis with higher resolution. The HREM image of TlBa2Ca3Cu4O11 was taken with the incident beam parallel to the a axis together with a structure model after image processing.

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