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The implantation-induced defects of crystalline silicon implanted with helium ions to a dose of 5 × 1016/cm2 at 600 °C were investigated. The sample was analyzed by transmission electron microscopy and high-resolution electron microscopy. Faceted cavities are observed in the damaged layer. Concurrently the distribution of interstitial-type defect clusters was investigated by conventional electron microscopy in bright and dark field. Many rod-like defects, which belong to {1 1 3}, {1 1 1} and (−2 0 0), are formed in the end of the projected range. In front of the damaged layer, some ribbon-like defects are formed, which belong to 〈2 0 0〉, 〈1 −1 1〉 and 〈1 3 −3〉. The possible reasons of the observed defect clusters are discussed.

Aberration-corrected electron microscopes currently dominate the high-resolution scene but they are not the only instruments that can provide such information. Other techniques are attracting attention, notably ptychography and the use of phase plates. Moreover, operation of these aberration-corrected microscopes at their ultimate performance raises questions that are still under discussion. We note too that correctors can be useful for tasks other than correction, such as vortex beam creation. To conclude, the specialized role of electron mirrors is recalled.

Twin boundary (TB) and twinning dislocations (TDs) in { 10 1 ¯ 1 } twins in deformed polycrystalline cobalt (Co) were studied by high-resolution electron microscopy. The { 10 1 ¯ 1 } TB tends to be flat and a mirror plane. The observed TD was characterized directly from the experimental image by the circuit-mapping method and predicted by the topological model. The observed TD with a localized core can stably exist in { 10 1 ¯ 1 } twins in Co.

High-resolution electron microscopy was applied to analyze the continuous precipitated particles of the γ-Mg 17 Al 12 phase with Pitsch-Schrader OR in the heat-treated AZ91 alloy at 473 K for 8 h. The existence of a continuous precipitated particle with the Pitsch-Schrader OR including the selection of the habit plane and the growth direction in Mg–Al system is rationalized by the constrained coincidence site lattice/constrained complete pattern shift lattice (CCSL/CDSCL) model and the O-lattice theory.

High-resolution electron microscopy is employed to observe the atomic arrangement of very tip of the growing martensite plate and that of the growing bainite. Transition lattice region with a certain dimension (more than a few nm), of which the structure is neither fcc nor bcc, but an intermediate one between fcc and bcc lattice, is found in martensite but not in bainite. Because of this fact, it is concluded that the martensitic transformation is of the shear-type transformation and the bainitic transformation is of the diffusion-type transformation.

Boron nitride (BN) nanohorns with various tip angles were synthesized by an arc-melting method, and atomic structure models for BN nanohorns were proposed from high-resolution electron microscopy. Stability and electronic structures of the BN nanohorns were investigated by molecular orbital/mechanics calculations, which indicated that multi-walled BN nanohorns would be stabilized by stacking of BN nanohorns. The energy gaps of the BN nanohorns were calculated to be 0.20∼0.85 eV, which are lower compared to those of BN clusters and nanotubes.

High-resolution electron microscopy, mass spectrometry and molecular mechanics/orbital calculations of the boron nitride-based clusters showed the formation of B 36 N 36 and Y@B 36 N 36 . Image simulations of these clusters confirmed the proposed structure model.

Atomic structures of surface and interface in (Hg,Tl,Pb)-based superconductors were investigated by high-resolution electron microscopy. The interfaces observed in Tl-based superconductors have the disordered region with ∼1 nm thickness, which would be suitable for barrier layers for tunneling junctions. Although the {001} planes of (Hg,Tl)-based oxides are fairly stable, most of the {100} planes are unstable, and atomic rearrangement was often observed. However, the HREM image of Hg 0.5 Tl 0.5 Ba 2 CuO 5 {100} showed the stable Ba–O–Ba layer at the surface, and oxygen atom positions were determined. The present study indicates that the surfaces of the Hg- and Tl-based superconductors are strongly dependent on the crystallographic planes and crystal structures.

Pd 80 Pt 20 and Pd 85 Pt 15 alloys were exposed at 673 K to a hydrogen pressure of 100 MPa for 4 h, which is called hydrogen heat treatment (HHT). After HHT the pressure composition isotherms at 273 K change remarkably and H-diffusion is enhanced. The change can be interpreted by a decomposition into a continuous Pd-rich and an embedded Pt-rich alloy. Direct evidence for this hypothesis is provided for the first time from high resolution electron microscopy. It will be shown that coherent platelets are formed after HHT which are two atomic layers thick and have an average diameter of ∼10 nm. Simulating the contrast observed in the electron microscope shows that the plates are Pt-rich.

Atomic displacements and interface reconstructions near a La0.9Sr0.1MnO3‐SrTiO3 interface are studied by use of the focal reconstruction technique applied in high-resolution electron microscopy. By using a quantitative model, column positions are determined with high precision (better than 0.004 nm) by least-squares minimization. A displacement vector map and interatomic distances are calculated. From these a structure model for the interface is proposed. The interface has a facetted shape, where the interatomic distance is modulated. Possible local oxygen deficiency in SrTiO3 near the interface has been observed. q 2000 Elsevier Science Ltd. All rights reserved.

The possibility of direct detection of doping atoms in the B12 cluster solid by high-resolution electron microscopy (HREM) was investigated by using calculated residual indices and difference images. The HREM images of B12-based rhombohedral boron doped with (Al, Cu) and carbon atoms were calculated at the Scherzer defocus. The difference images of Al2.6Cu1.8B105/B12 and B13C2/B12 showed Al, Cu and C atomic positions clearly at crystal thickness of 3.1 nm. Crystallographic image processing was applied to the experimental image of Al2.6Cu1.8B105, which provided the average Al and Cu atom positions. In addition, HREM images recorded from thin regions (

In the field of pharmaceutical applications relying on encapsulation of drug by polymer coating, capsules based on biodegradable polymers with mean size of about 500 nm have been obtained by a patented emulsion–diffusion method. The morphology, size and structure of the nanocapsules (NC) control their pharmaceutical properties, especially release of the drug. Here is reported a decisive contribution of transmission electron microscopy (TEM) in revealing the controlled form and size of the NC: mean size values measured by TEM do agree with data obtained by laser granulometry. Moreover, the TEM magnification allows an estimation of the membrane thickness.

As one of our systematic studies of the modulated structures of a series of new homologous compounds RM O 3 (ZnO) m ( R =Sc, In, Y, and La; M =In, Fe Ga, and Al; m =integer), this paper reports the modulated structure of Fe 2 O 3 (ZnO) 15 ( R =Fe; M =Fe) studied by high-resolution electron microscopy. It is found that the main and satellite spots in the diffraction patterns can be indexed as h a * + k b * + l c * + m q by considering a monoclinic unit cell of a =0.57 nm, b =0.33 nm, c =4.5 nm, and β =92° and a modulation wave vector of q=b * /34.8+c * /2. The possible space groups for the basic structure are C 2, Cm , and C 2/ m , and the possible four-dimensional superspace groups for the modulated structure are C C 2 1 , C Cm 1 , and C C 2/ m 1 1 . The crystal structure of Fe 2 O 3 (ZnO) 15 consists of Fe–O layers interleaved with 16 Fe/Zn–O layers. In the high-resolution image, the modulated structure appeared as zigzag-shaped contrasts among the Fe/Zn–O layers, where Fe is in high concentration. Compared with those of In M O 3 (ZnO) m ( R =In; M =In, Fe and Ga) reported in our earlier paper, the special features of the present modulated structure are the half-periodicity relative shift of the neighboring zigzag-shaped contrasts and the appearance of modulation within the Fe–O layers.

This article reviews the application of high resolution electron microscopy techniques to zeolite structural characterization. Examples given in this article include identification of structural intergrowth, stacking faults and framework projection net from high resolution images. Slow-scan CCD (charge-coupled device) cameras, representing the latest advance in electron microscopy instrumentation, are briefly introduced. Low-dose, high resolution electron microscopy using commercial CCD cameras is discussed. With slow-scan CCD cameras, it is shown that it is possible to directly read off the underlying zeolite structures from experimental high resolution images when suitable image processing techniques are employed. This latest advance greatly enhances the power of high resolution electron microscopy techniques in solving unknown zeolite structures.

Surface structures of the (Hg,T1)-based superconducting and related oxides were studied by high-resolution electron microscopy. The {100} planes of the 1201-type structure were found to be stable, and Hg0.5Tl0.5Ba2CuO5 showed a preferred atomic surface consisting of Ba layers. The {001} planes were also stable in HgTlBa2CuOx and TlBa2CaCu2O7. The present work indicates that the stable {100} planes of (Hg,Tl)-based superconducting oxides would be suitable for future device applications.

The internal structure of monodisperse CdS particles was investigated by high-resolution electron microscopy of thin sections prepared with an ultramicrotome. High-resolution images of the thin sections clearly revealed the arrangements and the crystallographic orientations of subcrystals as components of the particles. It was found that the central part of a particle was composed of randomly oriented small subcrystals about 10 nm in diameter, while near the surface of the particle, relatively large subcrystals about 50 nm in maximum width were observed. Furthermore, stacking faults and twins on the {1 1 1} planes were observed in the sections.

A method based on a simulated annealing algorithm is applied for the reconstruction of the projected crystal potential belonging to a periodic high-resolution electron microscopy exit plane wave function. Using simulated exit plane wave functions of GaAs at different specimen thicknesses, the convergence behaviour and the accuracy of the algorithm are investigated. It is demonstrated that the reconstruction is possible even under strongly non-linear scattering conditions at small specimen thicknesses. Further, the convergence of the algorithm to an ambiguous solution beyond a certain specimen thickness is discussed.

A new type of ordered structure in a Ti-48at%Al alloy quenched from the disordered α-Ti phase field has been determined by high-resolution electron microscopy and image simulation. The structure is based on an h.c.p. structure having an orthorhombic unit cell with the lattice parameters a = 0.45 nm, b = 0.28 nm and c = 0.49 nm, and belongs to a B19 type. The B19 TiAl can be described as the AB… stacking of close-packed /(111/) planes in γ-TiAl with an L1 0 structure, and the ordered arrangement of Ti and Al for the B19 structure is interpreted as a local arrangement in the sample.

Weak-beam and high-resolution electron microscopy of dislocations in CoSi2 with the Cl structure, introduced at room temperature by pulverization, has shown that dislocations with the 〈100〉 Burgers vector and those with 1/2〈110〉 are dissociated into partial dislocations by the following reactions: 〈100〉 1/2〈100〉 + 1/2〈100〉 on {001} 1/2〈110〉 1/4〈111〉 + 1/4〈111〉 on {110} 1/2〈110〉 1/6〈211〉 + 1/6〈121〉 on {111} Stacking faults and micro-twins have also been observed by high resolution electron microscopy. Evidence that vacancies are mobile at room temperature has been obtained by observations of helical dislocations.

A cubic member of the M41S family with a three-dimensional pore system, denoted as MCM-48, was synthesised. By combining X-ray powder diffraction (XRD) with high-resolution electron microscopy (HREM), a cubic symmetry with an Ia 3 d space group was determined for the as-synthesised and the calcined MCM-48 material. Upon calcination the unit cell decreased from around 10.09 nm to about 8.1 nm. The overall pore structure was found to be quite unaffected by local variations in the structure and the decrease in the unit cell size upon calcination.

Interface structures in nanocrystalline metals, ceramics, carbon-60 and their composites were compared, using high-resolution electron microscopy, to understand the origin of unusual properties reported systematically by Gleiter and the co-workers. The observations showed that voids are not to be an inherent structure of nanocrystalline materials. Atoms in the grain boundaries are found influenced by the two neighboring crystals just as in usual polycrystalline aggregates. No concrete evidence of nanocrystalline anomaly was found in the density of atoms in the grain boundaries.

Core structures of edge and screw dislocations in CoTi were studied by high-resolution electron microscopy (HREM). An HREM image of an edge dislocation showed that the spreading of the dislocation core was limited within a distance of about 1.2 nm. From an HREM image of screw dislocations in CoTi, it was shown that the core was spreading on the (010) plane and the spreading of the core was limited within a distance of about 1.8 nm. It was suggested that the core spreading on the {010} plane, which was different from the slip plane of {110}, affected the abnormal temperature dependence of yield stress of CoTi.

SSZ-25 has been known to have high catalytic activity, but no structure has been reported. A combination of electron microscopy techniques was employed to characterize this new zeolite. This allowed us to determine the unit cell and its relationship to the crystal morphology. The unit cell was hexagonal with a = 1.41 nm and c = 2.52 nm. The individual crystals tend to be thin flakes, and high-resolution electron microscopy (HREM) revealed that this zeolite has a multi-dimensional channel system. The results of this work showed that there are large-pore zeolite channels arranged parallel to the c direction. The HREM results, when taken with other physical characterization methods, confirmed why this zeolite has high catalytic utility.

The direct confirmation of the existence of Cd-stabilized β″″-ferrite prepared as a stable phase in a K2O-Fe2O3-CdO system was done by high-resolution electron microscopy. It was confirmed that the Cd-stabilized β″″-ferrite had a rhombohedral symmetry with lattice constants a = 0.600 and c = 5.026 nm. The structure is composed of an alternate stacking of ion-conductive layers and spinel-like blocks which have six cubic close-packed oxygen layers expressed as · · · A1(BCABCA)B1(CABCAB)C1(ABCABC)A1 · · ·. In addition, twins which had reversed stacking sequences were observed in the spinel-like blocks.

The damage induced by heavy ion irradiation in a wide palette of materials, extending from metals to insulators, is presented. The damage creation and the track morphology have been investigated by electron microscopy and especially HRTEM when available. It is shown that heavy ion irradiation in the electronic stopping power regime is a very efficient tool to amorphize the solids. But the sensitivity to irradiation of each material is strongly variable since the electronic stopping power threshold for damage creation can vary between 1 and 40 keV/nm. The wide difference in sensitivity to heavy ion irradiation between the insensitive materials such as some semiconductors and insulators and the very sensitive ones like the quartz and some magnetic ferrites is a real challenge for any general model of damage creation in solids.

Crystallization behavior of gold-implanted amorphous SiC was studied by high resolution electron microscopy. (1) Prior to crystallization, a concentration fluctuation of gold is induced in the amorphous matrix with annealing. The typical annealing temperature at which evolution of the fluctuation becomes evident is 1023 K. (2) With annealing at 1173 K, crystallization takes place locally and crystallites of β-SiC are formed. It is suggested that this initial crystallization occurs preferentially in the gold-depleted region. (3) With annealing at 1373 K, complete crystallization takes place; gold-implanted amorphous SiC eventually crystallizes into two phases: β-SiC and fcc gold.

In the objective lens alignment in transmission electron microscopy, there is usually some discrepancy between the incident beam directions required to satisfy the voltage-center condition or the coma-free condition. This is because an incident beam direction is found for the reference point conjugate to the screen center, while the reference point is usually not located along the lens-field axis. In this report it is demonstrated that the voltage-center alignment keeping the coma-free condition can be carried out by finding an object point on the lens-field axis. We propose to call this technique a lens-field center alignment. Since most microscopes have the deflector below the objective lens needed for this technique, the lens-field center alignment can be used in most microscopes.

The interface between vanadium and the basal plane of sapphire was studied by conventional and cross sectional high resolution electron microscopy (HREM) to clarify the atomic structure of the interface. A 50 nm thick vanadium film was deposited on the (0001) basal plane of sapphire by molecular beam epitaxy (MBE). The TEM observations of the interface were made from three directions: two cross-sectional views (parallel to [1 2 10]Al2O3 and [10 10 ]Al2O3) and plan view (parallel to [0001]Al2O3). From the SADP, the following orientation relationship was obtained: (111)V ‖(0001)Al2O3; [10 1 V ‖[1 2 10]Al2O3. Cross-sectional HREM observations showed the atomic configuration at the interface, and the existence of periodic arrays of geometrical misfit dislocations. Computer simulations show that sapphire is aluminum-terminated at the interface with vanadium.

High-resolution electron microscopy was performed on fine crystals with A-15 type structure prepared by vacuum-deposition of tungsten. The size distribution of the crystals with the A-15 type structure was ranged from 2 to 11 nm and was similar to that of the bcc type structure coexisting in the film, indicating that the nucleation of both structures generated at the same time in the initial stage of growth. The critical grain size of transformation from bcc to A-15 type structure was not observed in the nanometer-sized region. Coalescence of the nanometer-sized crystals with A-15 type structure was observed in the film. It was found that the crystals were connected by stacking faults with displacement vector of 1 2 〈100〉 and nanometer-sized tilt grain boundaries rotated by 30° around the 〈100〉 A-15 axis. It was also implied from the observation that the A-15 structure in the present film was stabilized by some kinds of lattice defects.

400 kV high-resolution electron microscopy is used to study the distribution of foreign atoms which are present in substitution in a Ni 3 Al intermetallic compound. The presence of elements heavier than Al can be detected in the images. It is shown that these elements are located on the Al sites. The contrast of atomic columns containing different elements is analysed by multislice calculation and image simulation. The contrast analysis combined with a statistical approach leads to an estimation of the overall composition which is in agreement with previous experimental results.

By rotation of carbon nanotubes about their long axis and obtaining images by high-resolution electron microscopy, it is shown that carbon nanotubes do not have a perfectly cylindrical shape especially near the ends of the tubes.

We investigate the effect upon HREM images of the static atomic displacements (SD) present in crystalline alloys with atomic size effect. Our method is to compare pairs of images of the same distributions of atoms (in III–V alloys) calculated with and without taking the SD into account. We show that large differences usually exist between these images, assess them quantitatively, and demonstrate that proper consideration of the SD is essential to achieve reliable composition analysis by HREM, in particular when the ‘chemical mapping’ technique is used. The effect of the SD depends on the specimen thickness and on the objective lens defocus.

C 60 crystals grown by vapour transport may exhibit rough surfaces depending on the cooling conditions at the end of growth. The rough surfaces are due to hillocks of about 0.1–0.3 μm on “002” and “111” faces. Hillocks on “002” faces are square pyramids bounded by “111” surfaces or surfaces deviating from “111”. Hillocks on “111” faces are triangular pyramids bounded by stepped “111” surfaces. The density of crystal defects in as-grown and cleaved crystals is much lower than in crushed crystals. The high density of defects in crushed crystals is induced by specimen preparation. HREM imaging and simulation has confirmed that the cleaved surfaces are clean and free of lattice relaxation.

High-resolution imaging of ordered polymers is described both theoretically and experimentally. The relationship between the actual three-dimensional specimen structure and the resultant two-dimensional image intensity distribution is developed using the multislice formalism. The influence of the electron optical conditions on the image is demonstrated with experimental data, as well as with image simulations. Practical details of specimen preparation, as well as the effects of specimen structural defects on the image, are presented. A significant challenge for polymer microscopists is to minimize the deleterious effects of electron beam damage and to identify image artifacts resulting from damage. Future applications of ultrahigh-resolution capabilities are illustrated with respect to direct imaging of the anisotropic potentials present in covalently bonded materials.

Planar defects in the infinite-layer (Sr 1− x Ca x ) y CuO 2 structure are believed to be responsible for superconductivity with T c up to 110 K. In this work we present χ 2 minimization results to best fit a set of through-focal HREM images of such defects. Optimized atomic positions of the defect with an error bar of about 0.1Aare determined. The experimental parameters for simulated defect images such as sample thickness and objective lens defocus are determined by χ 2 fitting of the corresponding experimental HREM images of the matrix.

90° domain boundaries in BaTiO3 and PZT(52/48) have been studied with high-resolution electron microscopy. The high-resolution images with two-dimensional 4 A lattice fringes show that most 90° domain boundaries in BaTiO3 are parallel to (011) planes but can shift from one (011) plane to adjacent (011) planes. It is suggested that such shifts may occur on (01 1 ) or (001) planes. Across the domain boundary, lattice planes tilt about 0.5° in BaTiO3, which is close to the experimental value 0.6° from the selected-area diffraction pattern and the theoretical value 0.57°. In PZT(52/48), the tilt of lattice planes across the domain boundary in high-resolution images is only about 1°, which is smaller than the experimental value 2.8° from selected-area diffraction pattern and the value from theoretical calculation. The mismatch may indicate that in very thin films the lattice distortion and strain field can be relaxed. A diffuse dark contrast is found along 90° domain boundaries in both BaTiO3 and PZT(52/48) and is probably related to the lattice distortion or ionic displacement. The diffuse dark lines are about 4–10 unit cells wide around the domain boundary. Diffractograms from Fourier analysis of the regions in high-resolution images around the domain boundaries reveal the effects of the lattice distortion and strain field.

High-resolution electron microscopy has been utilized to elucidate the structural nature of oxygen-containing planar inversion domain boundaries in aluminum nitride. A model for this defect is proposed which incorporates the necessary structural elements needed to describe the entire AlN-Al 2 O 3 system. Image simulations of the proposed defect structure, for a range of imaging conditions, are in excellent agreement with experimental micrographs and provide substantial evidence for the validity of the proposed model.

Recent grain boundary modeling studies in fcc metals have revealed global correlations between GB energy and (i) the rigid-body translation normal to the grain boundary (the so-called volume expansion) and (ii) the degree of deviation of the local atomic coordination across the interface relative to the ideal lattice. This communication describes an approach towards evaluation of such parameters by analyzing images obtained by axial high-resolution electron microscopy, utilizing digital image-processing techniques. Observations on several 〈1 1 0〉 tilt GB's in Au are presented.

High-resolution electron microscope (HREM) images of ω-phase crystals in Ti-11.1at%Mo alloy single crystals formed by aging are discussed by comparing with the calculated images. The calculation was carried out using the multi-slice method at different defocus values for ω-phase crystals at three different positions in the matrix. It is found that bright spots of HREM images of ω-phase crystals appear at the positions of atoms, which are displaced in the opposite direction and make atom pairs in the model, as was proposed by de Fontaine et al. This fact was previously predicted in 1987. It is also found that bright spots of HREM images appear at the position of atoms, which are not displaced in the model. These results suggest that the proposed model is satisfactory.

New methods for both qualitative and quantitative analysis of the GaAs/AlGaAs interface by high-resolution electron microscopy at 400 kV in

In the field of high-resolution transmission electron microscopy (HRTEM), the term “resolution” has come to hold a number of different meanings [M.A. O'Keefe and J.C.H. Spence, in: Proc. 49th Annual EMSA Meeting, p. 498]. The present work reviews the various definitions of HRTEM resolution, derives theoretical expressions for resolution, and suggests how high resolutions may be attained in practice.

Conventional methods of interpretation of HREM images rely on structure modeling followed by image simulation. These methods are inapplicable to the interpretation of micrographs of amorphous materials because the atomic structure is unknown a-priori. Previous experimental work by the present authors had indicated that the cross-correlation of intensity fields of different regions of an HREM micrograph can identify regions of structural order in an apparently random matrix. The present paper confirms this initial result by reporting results of cross-correlations on computer-simulated HREM images. The images were generated from a “multislice” calculation of electron-wavefront propagation through a composite material consisting of a Si crystallite affixed to a relatively thick amorphous Si substrate. The cross-correlation technique is shown to be capable of retrieving the c-Si region where the simulated HREM images reveal to evidence of the crystallite. There is an optimum microscope defocus for which retrieval of the ordered structure is most efficacious. The cross-correlation technique is found to be superior to conventional Fourier filtering for identifying regions of atomic order.

By making good use of the excellent properties of the imaging plate (IP), i.e., high sensitivity, a wide dynamic range and good linearity for electron intensity, high-resolution electron microscope (HREM) images were quantitatively analyzed. In W 8 Ta 2 O 29 , contrast changes due to the dynamical diffraction effect were quantitatively evaluated and compared with the simulated images. In Pb ( Ba , Sr ) 2 ( Eu , Ce ) 2 Cu 3 O y , which is related to high- T c superconductors, atomic columns containing heavy elements such as Pb were clearly distinguished from those of relatively light elements such as Cu. Furthermore, quantitatively evaluated contour maps revealed vacant oxygen positions, which are important in characterization of both the structure and the electrical properties of the high- T c superconductors. These results demonstrate that the IP is effective and indispensable for the quantitative analysis of HREM images as well as for electron diffraction patterns.

A preliminary HREM study of indialite (hexagonal α-cordierite Mg 2 Al 4 Si 5 O 18 ) is reported. Conditions under which the structure of this compound can be optimally imaged in the a and c projections are discussed for the case of a 400 kV microscope, with a Scherzer resolution of 0.17 nm. Both numerical simulations and experimental multi-beam micrographs demonstrate that the whole cation sublattice is imaged in the [0001] orientation, while only Al + Si atoms contribute directly to the image in the [2110] orientation.

The principle of image deconvolution in HREM by means of maximum entropy (ME) is introduced. The ME image deconvolution was performed in terms of a single image taken at an arbitrary defocus condition or in terms of the combination of an image with the corresponding electron diffraction pattern. The weighted ME method is introduced for crystals thicker than a weak phase object. The test results on simulated images of chlorinated-copper phthalocyanine for various defocus values are shown. The method is also efficient for crystals consisting of atoms with great differences in atomic weight and for very noisy images.

The outstanding merits of scanning transmission electron tomography as a technique for the investigation of the internal structure and morphology of nanoparticle and nanocluster materials are summarized with the aid of numerous typical illustrations. Reference is made also to the significant advances that have arisen in probing ultrastructural characteristics of nanoscale solids using aberration-corrected (AC) electron microscopy (EM). Information of a unique kind may be retrieved by combining the imaging and analytical power of ACEM.

Ferritic steels containing copper have been studied as model systems for cluster/precipitate formation in reactor pressure vessel steels. The samples were aged at 400 °C for 2000 h and subsequently analyzed using high-resolution electron microscopy. Direct evidence was found that, besides the 9R structure occurring, there exist also 2H variant and stacking faults in local regions of the same Cu precipitate. The 2H variant has a hexagonal unit cell with lattice parameters a = b = 0.254 nm and c = 0.417 nm and axial ratio c/a = 1.642.

Geometric phase analysis (GPA) is applied to determining the strain fields in AlSb/GaAs hetero-epitaxial film from high-resolution electron microscopy (HREM) images. The misfit dislocations along the hetero-interface are shown to be predominantly 90° Lomer dislocations. The epitaxial film is almost fully relaxed by a high density of misfit dislocations. The 90° Lomer dislocations are assumed to be formed by either recombination of two 60° mixed misfit dislocations through a glide and climb process or direct nucleation at the interface. The atomic steps (ASs) are visualized in the strain map, providing a new method for identifying the ASs at the interface.

We have examined the structure of a Cu3Au-type compound CeRh3B0.5 by means of electron diffraction and high-resolution electron microscopy. The observed electron diffraction patterns of CeRh3B0.5 show the appearance of 1/2 1/2 1/2-type superlattice reflections and fine satellite reflections around all reflections. These features have not been detected by X-ray powder diffraction study. The new ordered structure producing the superlattice reflections belongs to a tetragonal system, space group I4/mmm (No. 139) and cell parameters of a t = b t = a c 2 = 0.5795 nm and ct = 2cc = 0.8196 nm. The proposed model is characterized by ordering of both B atoms and Rh octahedrons. The observed high-resolution image taken with a diffraction pattern showing the satellite reflections along the [0 1 1] direction shows a domain structure with size of about 3 nm, and a lattice modulation and some edge dislocations have been observed at boundaries between the domains. It is suggested that the anomalous behavior of hardness in CeRh3Bx is caused by the appearance of this modulated structure.