Showing papers on "Transmission electron microscopy published in 1984"
TL;DR: In this paper, a technique for fabricating TEM specimens that can be viewed in cross-section is described, which can be readily adapted to the study of other systems, including silicon-based materials.
Abstract: The structure and chemistry of thin solid films are best studied by transmission electron microscopy (TEM) when they are viewed in cross-section—that is, when the surface normal of the film is made perpendicular to the electron beam. In this orientation, the substrate, the thin film layers, and the interfaces between them can be imaged either simultaneously or individually. Further, information from each of these regions remains distinct from that obtained from the others, eliminating the problems of superimposition that are a consequence of viewing a layered structure in the conventional manner (i.e., parallel to the surface normal). A technique for fabricating TEM specimens that can be viewed in cross-section is described here. Although the majority of our work is with silicon-based materials, the technique can be readily adapted to the study of other systems.
487 citations
TL;DR: Conventional and high-resolution imaging in the TEM demonstrated direct chemical bonding between bone and hydroxylapatite, and the bone at the ceramic surface was the same as normal bone away from the interface.
Abstract: The bone-hydroxylapatite interface has been examined directly in the transmission electron microscope (TEM). The bone-hydroxylapatite interface was characterized by using several electron microscopy techniques, including bright and dark field imaging, electron diffraction, high-resolution imaging, and energy dispersive analysis in the scanning-transmission electron microscope (STEM EDS). Mechanical grinding followed by argon-ion milling produced interface regions of unstained and undecalcified rat bone and hydroxylapatite that were transparent to electrons. Thus the exact location of the interface could be established and the bone at the interface studied. Conventional and high-resolution imaging in the TEM demonstrated direct chemical bonding between bone and hydroxylapatite. The bone at the ceramic surface was the same as normal bone away from the interface.
261 citations
TL;DR: A study of the distribution of Si in rice hulls was carried out to aid in understanding the observed formation of SIC whiskers by the thermal decomposition and reaction of these natural materials.
Abstract: A study of the distribution of Si in rice hulls was carried out to aid in understanding the observed formation of SIC whiskers by the thermal decomposition and reaction of these natural materials. Scanning electron microscopy, Auger electron spectroscopy, and energy-dispersive X-ray analysis confirm the presence of a major amount of Si in the inner and outer epidermal regions of the rice hull. The Si is present as a hydrated amorphous form of SiO2 which is evidently bound in the inner layer to organic constituents, placing it adjacent to a source of carbon but interfering with its solubility in HF. The SIC produced by pyrolysis is in the form of ultrafine particles with cubic crystal structure and whiskers exhibiting stacking faults and twins perpendicular to the whisker axis, easily visible by transmission electron microscopy. These whiskers are very similar to ones obtained by chemical vapor deposition with SiO and CO as the primary reactants.
196 citations
TL;DR: In this paper, the nature of the white layer formed on the running surface of a railway line has been investigated using transmission electron microscopy, and the results indicated that the layer is of an apparently fully "martensitic" structure and shows that the wear surface contains carbon in solution and is thus not substantially decarburized during service.
150 citations
TL;DR: In this article, a detailed study of a new process to produce amorphous binary alloys by solid-state reaction of the elemental constituents from an initially thin-layer configuration is presented.
Abstract: We report on a detailed study of a new process to produce amorphous binary alloys by solid-state reaction of the elemental constituents from an initially thin-layer configuration. The Ni-Hf system was selected on the basis of the criteria that a fast diffuser (Ni) and a large binary heat of mixing drives the solid-state reaction at temperatures so low (∼ 300 °C) that nucleation and growth of the crystalline phases are suppressed and the amorphous phase becomes the lowest accessible state of free energy. Backscattering spectrometry, x-ray diffraction, and transmission electron microscopy are used to monitor the atomic composition profile and the microstructure of the samples. The kinetics of the amorphous phase formation is consistent with the diffusion-limited growth of a laterally uniform amorphous layer. The substantial and approximately linear composition gradient of the amorphous layer reflects the low atomic mobility of the atoms in the amorphous phase and the broad existence range of the amorphous phase in the binary Ni-Hf system. The latter is consistent with predictions based on the calculated equilibrium free-energy diagram of the system.
120 citations
TL;DR: In this paper, the authors used high-resolution electron microscopy (HREM) and computerized image processing to determine the atomic coordinates (in projection) of metal atoms in a thin inorganic crystal, to an accuracy of 0.1 A.
Abstract: Modern electron microscopes have resolutions in the range 1.8–2.4 A which is, in principle, sufficient for structure determination at atomic resolution. High-resolution electron microscopy (HREM) has been widely used for studies of inorganic materials1, and computerized image processing of electron micrographs has been used for structure determinations of biological macromolecules2,3. Klug4 suggested that image processing could also be applied to electron micrographs of inorganic crystals. By combining the two powerful methods, HREM and computerized image processing, we have determined atomic coordinates (in projection) of metal atoms in a thin inorganic crystal, to an accuracy of 0.1 A. This high accuracy is mainly due to the noise reduction achieved through averaging over many identical unit cells.
104 citations
TL;DR: In this article, the surfaces of epitaxial CaF2 layers grown on (100 and (111) Si by molecular beam epitaxy have been studied using scanning electron microscopy.
Abstract: The surfaces of epitaxial CaF2 layers grown on (100) and (111) Si by molecular beam epitaxy have been studied using scanning electron microscopy. The (111) surface exhibits small triangular hillocks, while the (100) surface exhibits a columnar structure. This latter structure can be accounted for by the prohibitively large free energy of the (100) surface. A dipole moment exists perpendicular to this surface which causes the electrostatic energy to diverge. This phenomenon explains the inferior (100) growth as compared to (111) and has important implications for possible applications of group II‐A fluoride/semiconductor epitaxial structures.
87 citations
TL;DR: In this article, microstructural changes in self-implanted and arsenic-ionimplanted amorphous silicon layers as a function of energy density after pulsed ruby laser irradiation, using cross-section transmission electron microscopy and Rutherford backscattering.
Abstract: We have investigated microstructural changes in self‐implanted and arsenic‐ion‐implanted amorphous silicon layers as a function of energy density after pulsed ruby laser irradiation, using cross‐section transmission electron microscopy and Rutherford backscattering. In specimens irradiated with energy densities less than that required to cause complete annealing, we have identified two distinct regions; the first one consisting of fine polycrystals and the second one consisting of large polycrystals. The changes in thickness of these two regions as a function of pulse energy density are described. Concomitant changes in arsenic concentration profiles are consistent with diffusion in liquid silicon. From the profile broadening in the large polycrystalline region, the crystal growth velocity was estimated to be 4–6 ms−1.
84 citations
TL;DR: In this paper, the pyrolysis of triisobutylaluminum, an aluminum alkyl, at temperatures of 220-300 °C onto silicon, SiO2 and device wafer substrates was used to deposit aluminum films conformally in the 2.5 μm windows of a typical device.
77 citations
TL;DR: In this article, the homogeneity of the thin polythiophene films is very high, but it decreases when the film thickness is increased, and it is shown that the nature of the dopant strongly influences the film morphology.
Abstract: Polythiophene and substituted polythiophene can be electrochemically generated as very adhesive thin films or as thick powdery deposits. The homogeneity of the thin films is very high, but it decreases when the film thickness is increased. Scanning electron microscopy shows that the nature of the dopant strongly influences the film morphology. Transmission electron microscopy reveals mainly a fibrillar structure, with a fibril diameter of 200 A in the undoped state, and 800 A in the doped conducting state.
76 citations
TL;DR: In this paper, transmission electron microscopy, X-ray diffraction and photoluminescence were evaluated using GaAsP epitaxial layers emitting in the 1.25−1.37 μm wavelength region.
TL;DR: The effects of implantation temperature (Ti) on the chemical and physical structure of annealed high-dose oxygen ion implanted layers were investigated by Auger electron spectroscopy (AES) and transmission electron microscopy (TEM).
Abstract: The effects of implantation temperature (Ti) on the chemical and physical structure of annealed high‐dose oxygen ion implanted layers were investigated by Auger electron spectroscopy (AES) and transmission electron microscopy (TEM). At low Ti (∼400 °C) the buried oxide is bordered by layers of polycrystalline silicon (polysilicon) which, in the top silicon layer, is separated from damaged single crystal Si by a thin band of discontinuous oxide. These polysilicon layers are formed from amorphous regions during high‐temperature anneals. At high Ti (∼500 °C) polysilicon was not observed.
TL;DR: In this article, a computer-controlled VPE reactor for the growth of thin layer structures with abrupt composition changes was designed and built, which is used for MOVPE growth in the system GaAs to AlAs.
TL;DR: In this paper, a four-step fixation procedure including glutaraldehyde, OsO4, tannic acid, and uranylacetate application, in combination with critical point drying, drastically reduces structural damages.
Abstract: Monolayers of PtK-1 and HeLa cells grown on glass or plastic supports are extremely susceptible to lacerations, e.g., splits and cracks caused mainly by shrinkage when prepared for scanning electron microscopy (SEM). We find that a four-step fixation procedure including glutaraldehyde, OsO4, tannic acid, and uranylacetate application, in combination with critical point drying, drastically reduces these structural damages. In addition, the conductivity of the specimens is enhanced, so that they can be investigated without gold coating. Transmission electron microscopy (TEM) investigation of perpendicular sections in the area of lacerations provides evidence that the subcortical cytoskeletal elements are of crucial importance in maintaining cell membrane stability during the preparations. Our relatively quick and simple procedure results in an improved structural appearance of the cells.
TL;DR: In this article, InGaAsP and InGaP epitaxial layers lattice-matched to (001)-oriented GaAs substrates successfully grown by liquid phase epitaxy have been investigated by transmission electron microscopy, scanning transmission electron microscope and energy dispersive X-ray spectroscopy.
Abstract: InGaAsP and InGaP epitaxial layers lattice-matched to (001)-oriented GaAs substrates successfully grown by liquid phase epitaxy have been investigated by transmission electron microscopy, scanning transmission electron microscopy and energy dispersive X-ray spectroscopy. In both layers, periodic diffraction contrasts (modulated structures), are observed in two equivalent directions of the and the . Compositional variation has also been observed along these structures. These are associated with spinodal decomposition of the crystal during growth.
TL;DR: In this article, the authors used an electron energy loss spectrometer fitted to a transmission electron microscope (TEM) for a study of the structure of the thin layer of amorphous alumina (Al2O3) which is formed on aluminium by anodic oxidation in neutral sodium tartrate solution.
Abstract: The technique of extended electron energy loss fine structure (EXELFS) using an electron energy loss spectrometer fitted to a transmission electron microscope (TEM) has been applied to a study of the structure of the thin layer of amorphous alumina (Al2O3) which is formed on aluminium by anodic oxidation in neutral sodium tartrate solution. The EXELFS spectrum above the oxygen K-edge gives an Al-O bond length of 1–89 A, which is in good agreement with a previous measurement obtained from the electron-yield surface extended X-ray absorption fine structure (EXAFS) above the aluminium K-edge. The Al-O bond length derived from EXELFS measurements for the oxide film after crystallization in the electron beam shows that the structure of the crystalline phase is consistent with the reported structure of γ-alumina. Electron-yield surface EXAFS is generally a broad-beam technique, more applicable to in aitn studies of surface films. TEM EXELFS requires the films to be detached from their substrates, but t...
TL;DR: Although there was variation in the length of the various fibres among spermatozoa, the order of their termination was relatively constant and the relationship between these quantitative data regarding the structural characteristics of the dense fibres and the shape of the flagellar wave is discussed.
TL;DR: In this article, thin MoSe 2 films were prepared by r.f. planar magnetron sputtering and their morphological and growth characteristics were examined by scanning and transmission electron microscopy.
TL;DR: The method is applied to carbon films as test objects and compared the results with those obtained by transverse sectioning, STEM mass measurement, optical density and frequency change of a quartz crystal oscillator for thickness measurement of multilayered protein crystals and thin sectioned cells.
TL;DR: In this paper, the shape and orientation of individual oxide islands were examined by reflection high-energy electron diffraction in a XJHV chamber and then transferred, under vacuum, to a transmission electron microscope.
Abstract: Single-crystal copper specimens of various orientations have been cleaned, oxidized and examined by reflection high-energy electron diffraction in a XJHV chamber and then transferred, under vacuum, to a transmission electron microscope where the shape and orientation of the individual oxide islands could be examined. On all surfaces the islands had a regular appearance with three or four interfaces, the oxide interfacial planes were always {110} and fitted close to either {110} or {114} copper planes. Allowing for tilts of a few degrees, the same epitaxy was observed on all copper faces, the amount of tilt depending on the original surface orientation. Surface steps were shown to be a very important factor in the initial nucleation, influencing the adsorption of oxygen, the siting of the nuclei and the oxide orientation.
TL;DR: In this article, the effects of reactive I+ ion beams, derived from a source of solid elemental I, on In-containing compound semiconductors have been investigated using transmission electron microscopy.
Abstract: The effects of reactive I+ ion beams, derived from a source of solid elemental I, on In‐containing compound semiconductors have been investigated using transmission electron microscopy. The results are compared with the effects produced by beams of Ar+ and Xe+ inert gas ions. It is shown that the surface accumulation of metallic In due to the disproportionation normally associated with ion milling of these materials can be eliminated by the use of I+ ion beams. Transmission electron microscope specimens in cross‐sectional configuration are used to demonstrate the excellent results which may be obtained by I+ ion milling of InP and InSb.
TL;DR: The optical constants of evaporated MgF2 films were determined over the 1050–1600-A wavelength range from measured transmittance and near-normal incidence reflectance measurements and the complex refractive index was studied as a function of film deposition conditions and correlated with microstructural examinations by transmission electron microscopy.
Abstract: The optical constants of evaporated MgF2 films were determined over the 1050–1600-A wavelength range from measured transmittance and near-normal incidence reflectance measurements. The complex refractive index was studied as a function of film deposition conditions and correlated with microstructural examinations by transmission electron microscopy. Absorption by the low energy tail of an exciton band and scattering from inhomogeneities were found to account for the film’s loss in this wavelength range. Both of these factors were determined largely by substrate temperature during the film deposition.
TL;DR: This modified casting method enables one to represent the microvascular system of the rat brain three-dimensionally from embryonal day 17 onward and is hoped that this method will prove to be a useful tool in morphological vascular research on the nervous system.
Abstract: Vascular casting for scanning electron microscopic studies on microvascular architecture is in common use for various visceral organs in the field of anatomy. However, only a few studies have been performed on the brain using the previously reported casting method, and no detailed descriptions deal with suitable methodology for producing brain vascular casts. Our casting method, introduced here, for the CNS from the fetal to the adult stage involves the following modifications: (1) Perfusion fixation of the brain is carried out before injecting the plastic resin for casting into the cerebral blood vessels; (2) digestion of nervous tissue is accomplished with a sodium hydroxide and sodium hypochlorite solution; and (3) vascular casts are dried by a freeze-drying method, while the nondigested brain slices opposite the casts can be investigated with light microscopy and transmission electron microscopy. This modified casting method enables one to represent the microvascular system of the rat brain three-dime...
TL;DR: In this paper, high resolution surface imaging which gives directly the atom positions is tested for a single monolayer terrace on Ag (111) surface and the result shows the value of HREM for studies of surface crystallography.
Abstract: SUMMARY
Reconstructed structures at monolayer level on ‘clean and well-defined’ surfaces can be imaged by transmission electron microscopy in fixed beam illumination mode. The specimens are cleaned in-situ in the electron microscope in ultra high vacuum. Transmission electron diffraction pattern intensities can give useful information for determining the surface unit cell size of the structure, and the atom positions (geometric arrangement of atoms in the unit cell) especially those with a large unit cell, since the diffraction intensities are interpreted kinematically. High resolution surface imaging which gives directly the atom positions is tested here for a single monolayer terrace on Ag (111) surface. The result shows the value of HREM for studies of surface crystallography.
TL;DR: In this paper, a CdTe film was grown on InSb substrate and high-resolution transmission electron microscopy was used to characterize the film and interfacial microstructures.
Abstract: Epitaxial thin films of CdTe (1–5 μm) have been grown directly onto (001) InSb substrates or onto intermediate buffer layers of InSb (0.25–0.5 μm) by molecular beam expitaxy. Cross‐sectional transmission electron microscopy and high‐resolution transmission electron microscopy have been used to characterize the film and interfacial microstructures. Inferences about film quality were also compared with single‐crystal x‐ray rocking curve data and agreed well. Resulting microstructural features were correlated with various experimental growth parameters and substrate cleaning procedures. Results show that near‐perfect CdTe films can be grown on InSb substrates, but film quality is critically dependent upon substrate cleaning. Other factors observed to influence defect formation in the films include growth rate, total growth time, or a change in growth rate during film growth. Extended defects which form include twins, line dislocations, or looplike defects. Lattice imaging has demonstrated the lattice matching across the InSb film/InSb substrate interface, despite the formation of In precipitates during the heat cleaning procedure.
TL;DR: In this paper, the lines were written by electron beam radiolysis of a fine grain polycrystalline CaF2 film and reaction to CaO followed by development in H2O.
Abstract: We have fabricated 30‐nm lines on 200‐nm centers in CaF2 using a scanning transmission electron microscope. The lines were written by electron beam radiolysis of a fine grain polycrystalline CaF2 film and reaction to CaO followed by development in H2O.
TL;DR: In this article, high purity aluminium was oxidized in dried oxygen of atmospheric pressure at 673 and 913 K. The morphology of the oxide layers produced was investigated by optical microscopy methods (phase and interference contrast) and scanning and transmission electron microscopy.
TL;DR: The crystallographic structure of surface coatings produced by three topical fluoride agents deposited by a single application on intact human enamel surfaces was investigated by light- and dark-field transmission electron microscopy, as well as by electron and x-ray diffraction.
Abstract: The crystallographic structure of surface coatings produced by three topical fluoride agents deposited by a single application on intact human enamel surfaces was investigated by light- and dark-field transmission electron microscopy, as well as by electron and x-ray diffraction. The agents studied were an acidic silane fluoride lacquer, a neutral NaF lacquer, and an APF gel. The smallest coherently diffracting particles were CaF2 microcrystallites 4-15 nm in diameter. Large apatite-like crystals, approximately I μm in length, were also observed in the outer surface coating produced by the silane fluoride lacquer.