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IUCrJ 8(5), 1-4 (2021). doi:10.1107/S2052252521007879, Published by Chester

We report on formation of epi-layer of SixGe1-x by taking standard procedure in CMOS technology. The competitive process of solid solubility of Ge dopant into Si and SiO2 is the key to engineer atomically sharp, low defect very thin epitaxial layer at the interface of oxide-Si. Oxidation time process was used to control the distribution of the doped Ge ions at the interface of Si with oxide and in the oxide layer. Implanted samples (35 keV and 1 × 1016 Ge+/cm2) were oxidized at 1050 °C for 30–90 min. RBS-Channeling analysis shows two separate peaks of Ge corresponds to different depths after oxidation. Corroborate with high resolution microscopy and elemental analysis, we determined the first peak as enriched layer of SixGe1-x at the interface of SiO2single bondSi. Less than 10 nm epitaxially grown interfacial layer is very low in defects, and Ge ions are fully substituted into the host lattice. The second peak originated from diffusion of Ge into SiO2 resulted in a segregated layer containing Ge in oxide film. Technological demand on forming SixGe1-x layer for CMOS application through standard routes is what we address in this research. published

This work presents the use of high resolution electron microscopy (HREM) and geometric phase analysis (GPA) to measure the interplanar spacing and strain distribution of three gold nanomaterials, respectively. The results showed that the {111} strain was smaller than the {002} strain for any kind of gold materials at the condition of same measuring method. The 0.65% of {111} strain in gold film measured by HREM (0.26% measured by GPA) was smaller than the {111} strains in two gold particles. The presence of lattice strain was interpreted according to the growth mechanism of metallic thin film. It is deduced that the {111} interplanar spacing of the gold thin film is suitable for high magnification calibration of transmission electron microscopy (TEM) and the gold film is potential to be a new calibration standard of TEM.

Experiments on absorption of TmCl3 and Tm(NO3)3 from dry acetonitrile and aqueous solutions, respectively, were performed using carboxylated multiwalled carbon nanotubes with conic and cylindrical displacement of graphene layers. Using HAADF TEM imaging and EDX spectroscopy it was found that in the first case the chemisorption with complex compound formation with oxygen from carboxylated MWCNTs takes place while in the later this process is hampered by kinetic factor and side reactions with water. The data obtained are in good agreement with results of thermal-mass spectral and elemental CHNSO analysis. This particularity allows using transmission electron microscopy and related techniques for direct surveying of light atoms-containing groups on the surface of carbon materials. In the case of carboxylated cylindrical and conic MWCNTs it demonstrate that nanotubes in the second case are uniformly covered by functional groups while in the first – near the ends of tubes and the local defects along the surface.

We report on the results of analysis of the superdispersed product synthesized in a superfast jet of electric-discharge carbon plasma flowing to the nitrogen atmosphere. The data obtained by high resolution transmission electron microscopy indicate the presence of the α phase of hypothetic carbon nitride C3N4 in the form of unique quasi-two-dimensional multilayer particles.

The field ion microscope-atom probe and high resolution electron microscope have been used to study a rapidly solidified AlCr alloy. The material, containing 6.9–9.0 wt.% Cr, was produced by vapour deposition. In the as-deposited state, chromium-rich rod- or disc-shaped zones were found. The zones were about 5 nm in length, about 0.2–1.3 nm in width, parallel to {111} planes and along directions. In addition, a preliminary heat treatment was conducted. It was found that the zones remain relatively stable after annealing at 623 K for 15 min.

The perovskite compounds Ba0·6K0·4BiO3 and BaPb1−x Bi x O3 (x=0·9, 0·5, 0·25) have been investigated by high resolution electron microscopy and selected area electron diffraction. Several superlattices produced byin situ electron beam reduction have been observed. Ordered atomic arrangements in the reduced materials are discussed.

We unambiguously show that the signature of Te-rich bismuth telluride is the appearance of three new peaks in the Raman spectra of Bi2Te3, located at 88, 117 and 137 cm−1 . For this purpose, we have grown stoichiometric Bi2Te3 nanowires as well as Te-rich nanowires. The absence of these peaks in stoichiometric nanowires, even in those with the smallest diameter, shows that they are not related to confinement effects or the lack of inversion symmetry, as stated in the literature, but to the existence of Te clusters. These Te clusters have been found in nonstoichiometric samples by high resolution electron microscopy, while they are absent in stoichiometric samples. The Raman spectra of the latter corresponds to the one for bulk Bi2Te3. The intensity of these Raman peaks are clearly correlated to the Te content. In order to ensure statistically meaningful results, we have investigated several regions from every sample, We thank the Ministry of Finances and Competitiveness for its financial support through the grants CSD2010–0044 of the Programme Consolider Ingenio, MAT2012–33843, and MAT2011–27911 as well as the FPI programme for young researchers. We also thank the University of Valencia for the use of the supercomputer Tirant. Financial support from the European Research Council through ERC 2008 Starting Grant number 240497 is also gratefully acknowledged. Finally, we would like to thank Dr. Said Agouram for his help with the HRTEM measurements.

Molybdenum(VI) sulfide deposited on the surface of thermally exfoliated graphite has been reduced at 1273 K in dynamic vacuum conditions. High resolution transmission electron microscopy showed formation of layered particles with an average diameter of 20 nm which, using the Fourier analysis of images, were attributed to Mo3S4 phase. Graphite surface more likely promotes the transformation of MoS3 to Mo3S4 because the unsupported particles occurred in the sample have the MoS2 structure.

Morphology, distribution and crystal structures of age-precipitated particles in practical Cu-bearing steels with ultra-low carbon were studied by high resolution electron microscopy (HREM). The age-precipitation behavior was explored when poly-microalloying elements Cu, Nb, Cr, Mo and Ni were used and ɛ-Cu particles coexisted with carbides (carbonitrides) in steels. The fine dispersed ɛ-Cu particles and carbides of microalloying element Nb, Cr, Mo being about 10 nm only in size were observed in peak aging specimens and over-aging specimens. The twin structures and stacking faults in the particles and the transient structures formed in the early stage of the particle precipitation were also observed. The crystal structure of three types of age-precipitation particles was firstly identified by lattice streaks in HREM images of the single particles. The experimental method identifying crystal structure of fine and dispersed particles using HREM images of single particle was proposed.

Lead titanate nanopowders were fabricated by mechanochemical synthesis. The obtained materials were characterized by X-ray diffraction, high resolution electron microscopy and Raman scattering. The X-ray diffraction showed the perovskite structure of the powder. It was found that: (1) the powder consists of loosely packed grains with a broad distribution of sizes between a few nm and 45 nm, (2) the grains of sizes larger than about 30 nm exhibit well developed crystalline structure, (3) the Raman lines of PbTiO3 nanopowder exhibit a conspicuous broadening in comparison to Raman lines of the bulk material, and 4) in the spectrum of nanopowder the lines related to A1(1TO), E(2TO) and A1(3TO) modes are shifted into lower frequencies and their spectral linewidth increase and there is no significant change in frequency shift for the remaining modes. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

International audience; Ni clusters with an average size of 4 nm, supported on MgO micro-cubes were studied by high resolution electron microscopy (HRTEM) and image simulations by the multislice technique. Regular defects were evidenced in the metal clusters at the interface. Molecular dynamic calculations of a 4 nm cluster indicates the same type of defects.

In the present paper, we report the growth of rhodium nanoparticles passivated with n-alkyl thiol molecules using a new synthesis method which is a variation of the Brust phase transfer method. Our method yields extremely small nanoparticles ranging from 1–3 nm in diameter. Depending on the preparation, rhodium nanoparticles are very interesting for many potential applications; however, they are among the less understood noble metal nanoparticles. The synthesized nanoparticles were characterized by high resolution electron microscopy (HREM). This is the first report on the formation of many of the rhodium nanoparticle structures described herein.

An YNi2B2C thin film grown on a MgO(001) substrate by pulsed laser deposition has been investigated by transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). Plan-vi...

The structures and components of different pigments from the Feng Hui tomb situated in Bin County, Shaanxi Province, dated in the Five Dynasties (907–960 AD), were analyzed by Raman spectroscopy and high-resolution electron microscopy (HREM). It is shown that the red, yellow and black samples are cinnabar, PbSO4–PbO and carbon black, respectively, and well preserved, which provide scientific data for later conservation. Moreover, the results indicate that HREM and Raman analysis are very effective for identifying ancient inorganic pigments at low concentrations. Copyright © 2004 John Wiley & Sons, Ltd.

Growth of Ni on (001) Au has been widely studied. Furthermore it has been shown that a structural change occurs when an Au/Ni multilayer is heated up. This transformation can be described as an ordering which is unexpected from the equilibrium phase diagram. A high-resolution electron microscopy study of the transformation of a coherent Au/Ni multilayer is presented in this paper. The transformation has been characterized by in-situ HREM and by extensive image processings made on both simulated and experimental images.

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.

The contact resistance of Au/Ni/p-GaN ohmic contacts for different annealing conditions was measured. This was then correlated with microstructure, including phase distribution, observed by high-resolution electron microscopy combined with energy-filtering imaging. A contact resistance of 2.22 x 10(-4) ohms cm2 for Au/Ni contacts to p-GaN after annealing at 500 degrees C for 5 min in air ambient was obtained. NiO layers were identified at the interface and upper area of annealed Ni/Au/p-GaN for air ambient. In addition, an Au layer was found at the interface of p-GaN due to a reversal reaction during annealing. Identification of the observed phases is discussed, along with possible formation mechanisms for the ohmic contacts in the Au/Ni/p-GaN system.

The intermetallic phases of the binary system Al/Ni have attracted considerable effort in investigation, because of a wide field of technological applications. In our recent work we have demonstrated the influence of the microstructure on the early interreaction stages. Although the chemical and spatial information obtained by 3D-atomprobe analysis is unrivaled in resolution, identification of observed phases is only possible by use of complementary methods of investigation. The present paper describes the important role of high resolution electron microscopy for indentifying the structural nature of formed phases detected by 3D-atomprobe analysis. An outline of a model which might explain the different reaction paths in Al/Ni observed for different microstructures will be given.

A quantitative method is described for the measurememnt of displacements and strains by high-resolution electron microscopy. The image is considered to be composed of periodic sets characterized by Fourier analysis. The local amplitude and geometric phase of lattice fringes can be determined in this way. The analysis of the phase distribution leads to the determination of the local lattice configuration. The method is illustrated by different examples and its application conditions are discussed.

Bulk Nd-Al-Fe-Co glassy alloys with diameter up to 5 mm were investigated by magnetic measurements, magnetic force microscopy (MFM) and high resolution electron microscopy (HREM) at room temperature. The results from the measurement of vibrating sample ma

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.

As shown in Chap. 5, metakaolinite shows amorphous to words X-ray and spinel too is a very weakly crystalline material. In view of it, an extremely powerful technique high resolution electron microscopy is applied for characterization.

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.

Keywords: Bones ; electron diffraction ; high-resolution electron microscopy ; hydroxyapatite ; image processing ; image simulation ; micro- and nanoparticles Reference CIME-ARTICLE-1999-026doi:10.1046/j.1365-2818.1999.00608.x Record created on 2007-02-15, modified on 2017-05-12

Ion-beam sputtering deposition is very useful to a nonconductive specimen-preparation technique for ultra-high to high resolution electron microscopy. Application of the sputtering has modified the ion-beam thinning apparatus for preparation of the sample for TEM. Effective use of our modified sputtering apparatus leads to a good conductivity of the Pt-coating composed of finer particles in 1.7nm diamerter, and a surface of crystal can be closely observed under magnifi-cation of more than 100, 000.

The structure of the interfaces between Co silicide and (0001) SiC has been characterized mostly by high resolution electron microscopy and electron spectroscopic imaging. It has been found that, in general, there is no simple and systematic relationships at the silicide/ceramic interface and that there is no noticeable interdiffusion: the interfaces are chemically abrupt over 1.5 nm.

Quantitative high resolution electron microscopy has been used to study the atomic structure of grain boundaries in metals. An example of the Σ11 (113)/[ 140] symmetric tilt grain boundary in Al is given. Results for atomic column locations were compared quantitatively with atomistic simulations of the structure of the grain boundary using Embedded Atom Method (EAM) potentials and Local Density Approximation (LDA) methods. There is a statistically significant difference between the experimental image and the simulated image based on the EAM. The experimentally determined grain boundary structure is in better agreement with the LDA calculation.

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 surface diffusion process of tungsten (W) atoms and clusters on MgO(001) surfaces was successfully studied by time-resolved high resolution electron microscopy (TRHREM) in the time resolution of 1/60 s. The observation was realized by optimizing the thickness of MgO films and by using a special imaging technique, such as the off-Bragg HREM method. During the observation, W clusters composed of four and five atoms adsorbed on MgO(001) surfaces were detected in images reproduced from the videotape images. The multislice image simulation for the interpretation of the image contrast showed a possibility of discrimination of the atomic configuration of clusters such as "bcc," "on-top" or "fcc" type clusters, from the image contrast at the center of the clusters. The reason for the discrimination was clarified through the multislice image simulation, suggesting that the lattice mismatch between the clusters and the MgO lattice was a key factor in determining the image contrast.

The exact three-dimensional structure of a nanosized colloidal particle of Pd3 P was determined directly from high-resolution transmission electron microscopy (HRTEM) images that were recorded in several crystallographic directions. An HRTEM image recorded along [011] is shown on the right. The cores of the particles were excluded from the analysis because of severe multiple diffraction.

High resolution electron microscopy (HREM) is a technique which allows one to get information which by other techniques is difficult to obtain, in particular, for diluted systems as for example, catalysts. It provides a direct way to measure the lattice parameters of the chemical phases that are present in the sample and can provide complementary information by means of the surface image profile. In this work we measured the lattice spacings of crystal planes that appear in samples of molybdenum sulfide doped with Co, Ni and Fe, and to observe possible areas of insertion of these atoms between the MoS 2 layers.

HREM study of stacking faults in O-LiMnO2 is presented as a confirmation of the previous model obtained from XRD measurements.

Termination structures of surfaces of zeolite L crystals are studied by high-resolution electron microscopy (HREM). By comparing observed HREM images with simulated ones based on some ideal models ...

In the alloy Ti3 Al-Nb, several phases appear after cooling at various rates from a high temperature. These are B2, D0 (alpha-phase), L1 (eta-phase) and an 19 2 0 omicro-type phase. A high-resolution electron microscopy observation is presented - 1 of an alloy continuously cooled at 10 K s from 1200oC, which shows very small regions of the eta-phase at the boundaries between the alpha-phase and B2 phase. An opportunity is thus provided to observe the early stages of the formation of the eta-phase. Orientation relationships for the phases are given.

We have studied the Bi-Sr-Ca-Cu-O family by high resolution electron microscopy (HREM). We have simulated the HREM images using a phenomenological model. The experimental and calculated results agree quite well.

Guinier-Preston (GP1) zones in the model alloy Al-1.84 at. %Cu and in the industrial alloy Al1.68Cu1.10Mg0.33Mn at.% (Aa 2017A) were studied by means of high resolution electron microscopy. The experimental images are interpreted using multislice simulations. The majority of GP1 zones consist of atomic monolayers, the disc diameter ranging from 4 to 10 nm. In the binary alloy, double layer GP1 zones and unstable disc shaped particles on {111} planes were also found. The contrast of the GP1 zones is strongly dependent on their size, on the foil thickness, on the defocus of the objective lens, less sensitive to the Cu content and much less sensitive to the position of the GP zone in the depth of the foil.

In order to clarify the β → ω phase transformation mechanism in β-titanium alloys, an investigation of the atomic structure of Ti-Mo alloys at early stages of aging was carried out using high resolution electron microscopy (HREM), in situ HREM, and image-processing methods. The initial structure of ω-phase crystals was observed as a line structure of bright spots in the 〈111〉 directions with 0.28 nm spacing. The formation of the line structure was also observed with in-situ HREM. The appearance of the line structure was confirmed by an image contrast simulation method.

The strain compensation produced by heavy boron doping in Si1−xGex layers with x = 0.21, 0.26, and 0.34 grown by solid phase epitaxy on (001) Si wafers has been analyzed using high resolution electron microscopy, high resolution x-ray diffractometry, and ion channeling. The structure of the epilayers consists of a defect-free region located next to the layer-substrate interface and a top region which contains strain-relieving defects. In the undoped samples the defect-free layers are partially relaxed and their relaxation increases as the Ge fraction increases. Substitutional boron incorporated to the SiGe lattice to levels of 2.8 ± 0 3 × 1020 cm−3 during the growth process reduces the lattice mismatch between the epilayers and the substrate. The boron-doped, defect-free layers are thicker than the corresponding undoped layers of the same Ge content and their strain relaxation is lower. It has been shown that it is possible to grow at least 27 nm thick defect-free and fully strained heavily boron-doped layers with x = 0.21 by solid phase epitaxy.

The microstructural development during annealing in the supercooled liquid region of amorphous Pd 46 Ni 36 P 18 , which is supposedly of phase-separating composition, is compared and contrasted with those of Pd 48 Ni 32 P 20 and Pd 40 Ni 10 Cu 30 P 20 . High resolution electron microscopy showed that the as-quenched alloys were fully amorphous while atom probe field ion microscopy (APFIM) showed random solute distributions, typical of amorphous materials. Annealing in their respective supercooled liquid regions did not result in the formation of compositionally-modulated microstructures prior to the onset of crystallisation.