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• Usable specimen thickness of Si for lattice imaging on a TEM was evaluated. • The originally developed RM was used for this evaluation. • Lattice images are successfully observed for pattern with thickness of up to 508 nm. • However, the contrast of the lattice images at a thickness of 508 nm is not distinct. • The practical thickness for analysis is less than approximately 500 nm. We evaluated the usable specimen thickness of Si for lattice imaging on a transmission electron microscopy (TEM) instrument operating at 300 kV and equipped with a complementary metal-oxide-semiconductor camera by using an original reference material (RM) and comparing the lattice images obtained from Si patterns of the RM with various thicknesses. Lattice images of the {111} planes of crystalline Si are successfully observed for patterns with thicknesses of up to 508 nm. However, the contrast of these lattice fringes at a thickness of 508 nm is not distinct, even when recorded using a longer exposure time (5.0 s) than that required to obtain lattice images of patterns with thicknesses of 316 nm or less (0.5 s). Based on these results, we conclude that the practical thickness of crystalline Si specimens for accurate structural analysis and TEM magnification calibration via lattice imaging is less than approximately 500 nm under the experimental conditions. [ABSTRACT FROM AUTHOR]

We reported investigation of lattice resolution imaging using a Hitachi SU9000 conventional in-lens type cold field emission scanning electron microscope without an aberration corrector at an accelerating voltage of 30 kV and discuss the electron optics and optimization of observation conditions for obtaining lattice resolution. It is possible to visualize lattice spacings that are much smaller than the diameter of the incident electron beam through the influence of the superior coherent performance of the cold field emission electron source. The defocus difference between STEM imaging and lattice imaging is found to increase with spherical aberration but it is possible to reduce the spherical aberration by reducing the focal length (f) of the objective lens combined with an experimental sample stage enabling a shorter distance between the objective lens pre-field and the sample. We demonstrate that it is possible to observe the STEM image and crystalline lattice simultaneously. STEM and Fourier transform images are detected for Si{222} lattice fringes and reflection spots, corresponding to 0.157 nm. These results reveal the potential and possibility for a measuring technique with excellent precision as a theoretically exact dimension and established the ability to perform high precision measurements of crystal lattices for the structural characterization of semiconductor materials with minimal radiation beam damage. [ABSTRACT FROM AUTHOR]

Abstract: CdTe thin film was grown by metal organic chemical vapor deposition on cube-textured Ni substrate. The microstructures of the CdTe film and Ni substrate were studied using transmission electron microscopy (TEM) lattice imaging in cross sectional. The orientational relationships of multiple hetereoepitaxial domains in the CdTe film were examined by TEM diffraction. The observed epitaxy is [111]CdTe//[001]Ni. The adjacent domains in CdTe film have a 30° rotation with respect to each other as inferred by the observed different diffraction patterns obtained from different zone axes. The high resolution lattice imaging shows that lamellar twins dominate within each domain. Our results are compared with CdTe(111) film epitaxially grown on Si(001) substrate by molecular beam epitaxy reported in the literature. [Copyright &y& Elsevier]

Abstract: The ultrastructure of α-chitin microfibril produced by marine alga Phaeocystis was investigated by FT-IR spectroscopy, X-ray diffraction and electron microscopy. The average size of the microfibril was 17.1±1.8μm in length and 39.8±8.8nm in width. The FT-IR spectrum shows typical α-chitin pattern, and each band was sharper than crustacean chitin’s, indicating higher crystallinity of the Phaeocystis chitin. The X-ray diffraction gave crystallite size more than twice of crustacean tendon’s. The fiber diffraction pattern is consistent with previous studies with two-chains orthorhombic unit cell (), and refined unit cell dimensions are a =4.742 Å, b =18.871 Å, c =10.338Å. High-resolution electron microscopy of ultrathin sections gave the cross-sectional shape of microfibril as hexagon. The lattice images of (020) plane (d =0.94nm) were frequently observed extending the entire cross-section of microfibril, indicating its single crystalline nature. These results allowed construction of a molecular packing model for α-chitin crystal. [Copyright &y& Elsevier]

A geometric phase analysis has been applied to high-resolution transmission electron microscopy images from algal cellulose microcrystals. The pictures were decomposed into images containing selectively the amplitude or phase information associated to selected Bragg reflections. Compared with Iβ (monoclinic)-rich cellulose microfibrils, Iα(triclinic)-rich microfibrils were found to be more heterogeneous when viewed along the H-bonding sheets. As a microfibril twist and radiation damage could not be totally ruled out as having an effect on the lattice image, this result has to be considered with care when used in order to survey the distribution of different allomorphs in a cellulose microfibril. However, the geometric phase analysis of noisy low dose high-resolution images appears as a promising new method to investigate polymer crystals and the distribution of domains having different structures or containing lattice distortions. [Copyright &y& Elsevier]

For utilizing the full capabilities of quantitative high-resolution transmission electron microscopy in materials characterization, a precise knowledge of the various aberrations blurring the object information is essential. Here, we describe an extended approach to the detection and quantitative assessment of image aberrations from lattice images of crystal samples. The approach is based on a theoretical analysis of five-beam lattice images in the presence of all relevant optical aberrations and for partial beam coherence. Compact analytical expressions for linear and nonlinear image Fourier coefficients as explicit functions of the aberration parameters are derived. In particular, a fundamental relationship between the occurrence of erroneous image symmetries and the simultaneous presence of optical misalignments and partial beam coherence is established. An image analysis procedure is proposed which allows for the detection of even- and odd-order residual aberrations and for the quantitative determination of defocus, two-fold astigmatism and axial coma if the three-fold astigmatism is known. For coma-free images, the three-fold astigmatism can also be determined quantitatively. Moreover, the procedure allows for a reliable detection of crystal misalignment for images of wedge-shaped crystal samples. [ABSTRACT FROM AUTHOR]

HRTEM images are traditionally interpreted by comparing experiment and simulation. However, quantitative agreement between experimental and simulated images is rarely achieved. It is thus highly desirable to extract quantitative information from HRTEM lattice images directly, without recourse to simulated images. Such ‘direct’ methods have been used to obtain high-resolution composition maps from the local information content of HRTEM images. We review the real-space techniques QUANTITEM and chemical mapping and delineate their application range. Finally, we demonstrate that both methods can be regarded as limiting cases of a more general approach. [ABSTRACT FROM AUTHOR]

The lattice imaging technique of high resolution electron microscopy has emerged to be a powerful method for investigating ultramicrostructures of crystals at the unit cell level. This technique can indeed be considered to be crystallography in real space. In this article, the principles and applicability of lattice imaging have been discussed along with a variety of applications. The applications discussed include the study of structures of solids, defects and dislocations, topochemistry of solid state reactions and silicate minerals. [ABSTRACT FROM AUTHOR]

Existing amorphous alloys are often heterogeneous when they are observed in a high resolution electron microscope. Fine crystal-like domains and chemical fluctuations were found to characterize the specimens. The structural features were classified and the significance was discussed from the viewpoint of high resolution electron microscopy. [ABSTRACT FROM PUBLISHER]

The chemical compositions of the grain boundary phases of silicon nitride (SiN) ceramics containing additives of 1 mole% and 10 mole% of an equi-molar mixture of YO and NdO have been studied by 300 kV field emission analytical electron microscopy. The energy dispersive x-ray spectra (EDS) are obtained from both two-grains and triple-grain junctions, where an electron beam of about 0.5 nm in diameter is focused. The thickness of the intergranular thin film is found to be about 1 nm, whose value is almost the same between two samples. The sintering additives are highly enriched at the triple-grain junctions, while they are less concentrated at the two-grain junctions. It is also shown that the additives are distributed inhomogeneously within the triple-grain junctions. Based on the composition analysis among the grain boundaries, an inhomogeneous grain boundary composition model for the SiN ceramics is proposed. [ABSTRACT FROM AUTHOR]

The hydrolysis and dehydration products of synthetic octacalcium phosphate (OCP) were studied using X-ray diffraction, infrared spectroscopy, chemical analysis, and high-resolution electron microscopy (HREM). A 'collapsed OCP' phase, identified by a characteristic 16.5 Å reflection in its X-ray diffraction pattern, was observed when OCP was dehydrated. High resolution electron microscopy of the hydrolyzed and partially hydrolyzed reaction products also revealed local contrast features with an approximate 16.5 Å periodicity. These features were consistent with a collapse of the OCP crystal structure and subsequent formation of epitaxial intergrowths of OCP and hydroxyapatite. Chemical analysis and X-ray diffraction of these samples were similar to previously reported calcium-deficient apatites. The hydrolysis of OCP to form calcium-deficient apatities is a reaction pathway which may be of importance in understanding the crystallographic changes occurring during the early stages of bone, calculus, and dental enamel formation. [ABSTRACT FROM AUTHOR]

Pristine and iodinated (SN) were studied by high resolution electron microscopy. High resolution electron micrographs showing lattice fringes up to 0.22 nm were obtained. In these electron micrographs, the texture of (SN) crystals was elucidated to be fibrillar or mosaic; the lattice fringes were observed in domains extended along the molecular axis (b-axis) and very narrow in the perpendicular direction. Each crystallite varied from place to place in size but maintained the b-axis orientation. The high resolution image of iodinated (SN) did not show directly the location of iodine atoms and their presence was deduced only from the optical transform of the image. The optical transform showed that iodine atoms were not intercalated uniformly, but localized at the skin region on (SN) fibers, where the crystal lattice was highly distorted. Then the iodination of (SN) is supposed to result in the destruction of the crystal lattice by invasion of iodine atoms or to take place preferentially at a distorted crystal region. [ABSTRACT FROM AUTHOR]