Showing papers on "Transmission electron microscopy published in 1973"
TL;DR: In this paper, single crystal samples have been irradiated in a high voltage (1 MeV) transmission electron microscope and the defects formed are described as a function of specimen temperature and compared with similar defects formed by proton irradiation in an accelerator-electron microscope link.
Abstract: Silicon single crystal samples have been irradiated in a high voltage (1 MeV) transmission electron microscope. The defects formed are described as a function of specimen temperature and compared with similar defects formed by proton irradiation in an accelerator-electron microscope link. The defects are contrasted with those obtained with heavy ions with particular regard to possible mechanisms for the crystalline to amorphous transition which was not seen for electron and proton bombardments. For irradiations at 450°C needle-shaped precipitates were formed on {113} planes.
95 citations
TL;DR: In this article, an analysis of the coherency strain field images indicates that the zones are of interstitial character and produce elastic displacements of 0.3 to 0.9 A normal to the habit plane.
55 citations
TL;DR: In this article, the effects of high-dose helium release, bubble and blister formation on the surface and in the bulk of high dose helium implanted palladium have been studied using helium mass spectrometers, scanning electron microscopy, transmission electron microscopes, and x-ray diffraction.
Abstract: Helium release, bubble and blister formation effects on the surface and in the bulk of high dose helium implanted palladium have been studied using helium mass spectrometry, scanning electron microscopy, transmission electron microscopy, and x-ray diffraction. The dependence of these effects on implantation dose up to 2 × 1018 He atoms/cm2, implantation temperature (− 180°C to + 200°C) and limited pretreatment has been investigated. A strongly dosc dependent low temperature (− 180°C to 200°C) fractional helium release and accompanying surface deformation was found at high doses, and a qualitative model for these low temperature results is presented.
46 citations
TL;DR: In this paper, the development of environmental cells for transmission electron microscopy is briefly reviewed and the advantages of increased penetrating power and large available space for specimen stages associated with high voltage microscopes are demonstrated.
Abstract: SUMMARY
The development of environmental cells for transmission electron microscopy is briefly reviewed. The advantages of increased penetrating power and large available space for specimen stages associated with high voltage microscopes are demonstrated. The effect of specimen-electron beam interactions are considered and the applications of the high voltage microscope to in situ studies of chemical reactions and biological material in the wet state are discussed.
40 citations
TL;DR: In this paper, the angular and energy characteristics of the transmitted electron beam are important in the determination of the effects of phase shifts introduced by the spherical aberration and the chromatic aberration of the objective lens.
Abstract: Publisher Summary This chapter describes image formation in the electron microscope with particular reference to the defects in electron-optical images. In the transmission electron microscope, information on the structure of a specimen, through its electron scattering properties, is transmitted to an image plane by a set of electron lenses. The intensity distribution, with respect to the angular deviation and the energy change of the incident electron beam, may be determined experimentally, but the information required on the amplitude and phase of the scattered electron wave may be inferred only by a detailed comparison of theory and experiment. The formation of an image from the scattered wave may be expressed mathematically in terms of a Fourier transformation. The chapter states that the angular and energy characteristics of the transmitted electron beam are important in the determination of the effects of phase shifts introduced by the spherical aberration and the chromatic aberration of the objective lens.
37 citations
TL;DR: In this article, a systematic account of electron scattering and image formation for amorphous and paracrystalline (especially biological) material is given, where contrast mechanisms in both elastic and inelastic scattering are discussed, under both scattering contrast and phase contrast conditions.
Abstract: SUMMARY
A systematic account is given, in relation to amorphous and paracrystalline (especially biological) material, of electron scattering and image formation for the range of electron energy from 50 to 100 keV. Contrast mechanisms in both elastic and inelastic scattering are discussed and image formation is considered under both scattering contrast and phase contrast conditions.
37 citations
TL;DR: In this paper, the effect of Ni-Al2O3 particles on the onset of recrystallization at elevated temperatures (up to 1400°C) has been studied and it has been shown that the particles are the most effective in stabilizing the electrodeposited structure.
Abstract: Dispersion-hardened nickel has been produced by electrodepositing Ni from a Watts' bath containing Al2O3, TiO2 and ZrO2 particles (0.005–0.06μm) in suspension. The effect of these particles on the onset of recrystallization at elevated temperatures (up to 1400°C) has been studied and it has been shown that Al2O3 is the most effective in stabilizing the electrodeposited structure. Thin films of Ni-Al2O3 examined by transmission electron microscopy showed a high dislocation density and restricted twinning, the Al2O3 particles being present both within the grains and at the grain boundaries. For optimum thermal stability the oxide should be present in the nickel matrix as discrete particles, but electron microscopy has shown that in all cases agglomeration occurs and that the particles are present as large clusters. Attempts to avoid this difficulty have proved unsuccessful.
33 citations
TL;DR: In this article, an optical and electron microscopy study of the nucleation and growth of stacking faults in epitaxial silicon has been carried out following pretreatment of the crystal in hydrofluoric acid and thermal oxidation in steam at 1050°C.
Abstract: An optical and electron microscopy study of the nucleation and growth of stacking faults in {001}‐oriented epitaxial silicon has been carried out following pretreatment of the crystal in hydrofluoric acid and thermal oxidation in steam at 1050°C. A direct correlation of the etched surface structure as revealed by interference contrast optical and scanning electron microscopy with substructural defects as revealed by transmission electron microscopy has been established for times ≥1 min. The observations are divided into five stages which, taking the TEM observations as a reference, are (i) formation of a needle‐shaped precipitate at the Si–SiO2 interface; (ii) nucleation of an interfacial Frank dislocation; (iii) climb of the Frank dislocation into the silicon substrate; (iv) formation of an equilibrium‐shaped stacking fault; and (v) stacking‐fault interactions.
32 citations
TL;DR: In this paper, the authors investigated the crystalline quality of (100) and (111) Si layers on spinel or sapphire substrates using ion channeling and electron microscopy.
Abstract: The crystalline quality of heteroepitaxial (100) and (111) Si layers on spinel or sapphire substrates has been investigated using ion channeling and electron microscopy. Ion channeling and backscattering give the depth profile of the density of imperfections, and electron microscopy is used to determine the nature of the imperfections as well as give an additional determination of their density. Transmission electron microscopy indicates that stacking faults and microtwins are the dominant types of imperfections in the layers, and these defects are interpreted to be the primary source of scattering centers for the channeled ions. Both channeling and scanning electron microscopy measurements indicate that the density of imperfections decreases with increasing distance from the interface. At equal distances from the interface a lower density of imperfections was observed in the Si layer for (111) Si/spinel and (100) Si/sapphire as compared to (100) Si/spinel. Large differences in the rate of decrease of the density of imperfections were observed for (100) Si/sapphire from different suppliers. The interpretation of the influence of the fault planes on channeling has been achieved by modeling the scattering by these defects. Semiquantitative correlations of scattering center densities from electron microscopy and channeling measurements indicate higher absolute densities for the channeling results, while relative densities determined at various depths by these two techniques are in agreement.
30 citations
23 citations
TL;DR: In this paper, it was shown that surface-controlled recrystallization may occur in drawn polyethylene films, where the fiber texture of the drawn film is replaced by a new texture having the (ITO) planes parallel to the film surface and the [001] axis in the drawing direction.
Abstract: Experimental observations by means of transmission electron microscopy and electron diffraction are reported which suggest that surface-controlled recrystallization may occur in drawn polyethylene films. During the re-crystallization process, crystals with (ITO) planes parallel to the free surface of the film grow from the surface into the drawn material. If the entire film is recrystallized the fibre texture of the drawn film is replaced by a new texture having the (ITO) planes parallel to the film surface and the [001] axis in the drawing direction.
TL;DR: In this paper, it was shown that molten polyethylene films with a thickness of about 200 A have a structure similar to that of a liquid crystal, and that the folding chains of folded chain molecules are aligned normal to the plane of the film.
Abstract: Observations by transmission electron microscopy and electron diffraction experiments are reported which suggest that molten polyethylene films with a thickness of about 200 A have a structure similar to that of a liquid crystal. The molten films consist of folded chain molecules the axes of which are aligned normal to the plane of the film. Solidification of the film results in the formation of large polyethylene single crystals (diameter 0·4 mm or more).
TL;DR: A technique for preparing thin foils of glass-ceramics for transmission electron microscopy has been developed, using a combination of chemical, abrasion and ion-beam machining.
Abstract: A technique for preparing thin foils of glass-ceramics for transmission electron microscopy has been developed, using a combination of chemical, abrasion and ion-beam machining This has permitted a study of the microstructural development in a number of glasses of different chemical compositions subjected to various heat-treatments Results are presented and discussed for materials based on the Li2O-SiO2 system and on a more complex Li2O-K2O-ZnO-SiO2 material employing phosphorus pentoxide as a nucleation catalyst
TL;DR: In this article, it was shown that the presence of axial ridges on the initial fiber leads to the development of striations perpendicular to the axis of the thinned specimen, and an analysis of the variation of ion incidence angle on a rotating cylinder enables the change in shape of a fibre on sputtering to be explained.
Abstract: Thinning by ion-bombardment is a useful technique for the preparation of carbon and other fibres for transmission electron microscopy. It is shown that the presence of axial ridges on the initial fibre leads to the development of striations perpendicular to the axis of the thinned specimen. An analysis of the variation of ion incidence angle on a rotating cylinder enables the change in shape of a fibre on sputtering to be explained; scanning electron microscopy of sputtered fibres confirms these conclusions. A mechanism for the formation of striations perpendicular to pre-existing ridges on the fibre is proposed.
TL;DR: In this paper, dislocations and inclusions in neodymium-doped yttrium aluminium garnet were observed by transmission electron microscopy and diffraction patterns from the inclusions showed them to be single crystals of the orthorhombic Yttrium aluminate perovskite type.
Abstract: Dislocations and inclusions in neodymium-doped yttrium aluminium garnet were observed by transmission electron microscopy. Network dislocations on {111} planes are parallel to 〈110〉 directions and appear to be undissociated. Electron diffraction patterns from the inclusions show them to be single crystals of the orthorhombic yttrium aluminate perovskite-type. Electron microprobe analysis of similar inclusions indicates that they are crystals of yttrium neodymium aluminate, Y1-xNdxAlo3 (x 0.4). An orientation relationship between the inclusions and the garnet matrix is suggested.
TL;DR: In this article, the Phillips EM 200 electron microscope was equipped with a "microgun" source to minimize heating of the specimen and to improve contrast and high resolution (HREM) images of the (001) chlorite crystallographic planes spaced at 13.9A intervals.
Abstract: Mafic chlorite from Benton, Arkansas was comminuted by rotary blending of a suspension, and the -- 2 ~m fraction separated by sedimentation in H~O. Droplets of suspension of the < 2 ~m fraction were dried on a layer of Epoxy resin and then addit!onal Epoxy was added and heat-cured at 48~ to form a resin sandwich. Cross-sections of 600-900 A thickness were cut on a Reichert auto- mated ultramicrotome. The sections were collected on standard electron microscope specimen screens, reinforced by vacuum evaporated C and examined by transmission electron microscopy (TEM). The Phillips EM 200 electron microscope was equipped with a "microgun" source to minimize heating of the specimen and to improve contrast and high resolution (HREM). Images of the (001) chlorite crystallographic planes spaced at 13.9A intervals were visible on many of the particle sec- tions. Imaging of the planes depended upon their being nearly parallel to the electron beam (within 0 ~ 10') and therefore, many particles which had other orientations did not show the 13.9A image. Micrographs made beforeoappreciabte irradiation by the electron beam revealed images of fringes corresponding~ to the 7-22 A (002) spacing of chlorite. Loss of the 7.22 ~ fringes and reinforcement of those at 13.9A resulted from heating of the chlorite in the electron beam. This behavior is analogous to the well-known crystallographic effects of heating chlorite at 550-760~
TL;DR: In this article, a miniaturized simple ion gun was constructed for this purpose, which was incorporated into an UHV electron microscope specimen chamber with hot stage in such a way as to permit bombardment of the substrate specimen while observing it by transmission electron microscopy TEM, and the ion beam generated is confined well enough to cause a sputtering removal of substrate material at a rate of approximately 5-10 A/min.
Abstract: A prerequisite for conducting valid corrosion experiments by in situ electron microscopy techniques is not only the achievement of UHV background pressure conditions at the site of the specimen but also the ability to clean the surface of the thin metal substrate specimen before initiation of the corrosive interaction. A miniaturized simple ion gun has been constructed for this purpose. The gun is small enough to be incorporated into an UHV electron microscope specimen chamber with hot stage in such a way as to permit bombardment of the substrate specimen while observing it by transmission electron microscopy TEM. It is shown that the ion beam generated is confined well enough to cause a sputtering removal of substrate material at a rate of approximately 5–10 A/min and to prevent the sputter deposition of contaminating material from the specimen holder. Thin single crystal Ni (100) film samples were used to demonstrate the applicability of the sputter cleaning technique, to show the removal of ion beam induced radiation damage by annealing, and to evaluate preliminary oxidation tests by selected zone dark-field microscopy.
TL;DR: Scanning electron microscope utilizing critical point drying was used in parallel with light and transmission electron microscopy to study L colonies produced by a stable L-phase variant of Staphylococcus aureus (AH24H).
Abstract: Scanning electron microscopy utilizing critical point drying was used in parallel with light and transmission electron microscopy to study L colonies produced by a stable L-phase variant of Staphylococcus aureus (AH24H)
TL;DR: In this article, a single-crystal copper film was examined by transmission electron microscopy and high-resolution electron diffraction and it was found that the misfit was less than that of vapour-deposited films at corresponding thicknesses.
TL;DR: In this paper, the authors consider the difficulties encountered in conventional thin-foil electron microscopy of alkali halides and demonstrate how each can within certain limits be overcome by careful thinfoil specimen preparation and examination at liquid helium temperature.
Abstract: This paper considers the difficulties encountered in conventional thin-foil electron microscopy of alkali halides and demonstrates how each can within certain limits besuccessfi~lly overcome. The measures required include careful thin-foil specimen preparation and examination at liquid helium temperature. I n particular, low temperature nlicroscopy is shown to significantly retard the onset of observable radiation damage effects induced by the investigating electron bearn. A brief account of the application of these techniques to studies of irradiation defect aggregations and dislocation behaviour in irradiated and deforliied alkali halide crystals is presented.
TL;DR: Red blood cells and bacteria have been viewed under the high voltage transmission electron microscope, using a controlled environment chamber, to compare with those obtained by phase contrast light microscopy and the potentialities of the system discussed.
Abstract: SUMMARY
Red blood cells and bacteria have been viewed under the high voltage transmission electron microscope, using a controlled environment chamber. Red cell changes on introduction of an agglutinating serum into the environment and bacterial changes on addition of an antibiotic, were observed. The results are compared with those obtained by phase contrast light microscopy and the potentialities of the system discussed.
TL;DR: In this article, the authors applied transmission electron microscopy to the study of damage in gold irradiated with 35 keV He+ ions to fluences of 1014 to 1016 ions/cm2.
Abstract: Transmission electron microscopy has been applied to the study of damage in gold irradiated with 35 keV He+ ions to fluences of 1014 to 1016 ions/cm2. Damage in as-irradiated specimens consisted of dislocation loops showing double arc contrast which loop analysis revealed to be about 30% to 50% interstitial in nature. Depth distributions of the defect clusters were determined using stereo microscopy. Annealing at increasing temperature resulted in a decrease in loop density together with an increase in loop diameter. Voids formed at annealing temperatures between 0.5 Tm and 0.58 Tm on and in the vicinity of dislocation tangles formed from the loops, and were identified from a through-focus sequence of micrographs and by kinematical imaging. Increasing void diameter with decreasing void density on annealing at higher temperature indicated that the voids were gas filled and were growing via migration and coalescence.
TL;DR: The transition from the complex {110} orientation to the {001} orientation is described in detail in terms of its dependence on the deposition temperature, film thickness, vacuum, and substrate conditions.
Abstract: CaF2 films, 30–1500 A thick, were vapor deposited at 25–380 °C onto air‐cleaved and vacuum‐cleaved NaCl in residual gas pressures of order 10−5, 10−7, and 10−9 Torr. The structures of the films were examined by in situ ultrahigh‐vacuum reflection high‐energy electron diffraction, conventional transmission electron microscopy, transmission electron diffraction, and surface replication techniques. The films consisted of many crystallites, the complex {110} and {001} orientations of which depended on the deposition parameters. The transition from the complex {110} orientation to the {001} orientation is described in detail in terms of its dependence on the deposition temperature, film thickness, vacuum, and substrate conditions. The {001} orientation was identified with two sets of thin needle‐shaped crystallites oriented at 90° to each other. The {110} orientation was identified with two sets of larger crystals also oriented at 90° to each other. At higher deposition temperatures the larger crystals formed ...
TL;DR: In this article, small 3D nuclei formed at the start of deposition and became continuous at an average thickness of ≈50 A. Contrast phenomena as well as the results of misfit measurements suggested that the lattices were initially strained to give a coherent nickel-copper interface.
01 Jan 1973
TL;DR: The initial stages of sintering have been studied by transmission electron microscopy as mentioned in this paper, where single crystal disks 10 to 20 microns in diameter and thin enough for electron transmission were produced by ion etching suitably masked silver films grown epitaxially on sodium chloride.
Abstract: The initial stages of sintering have been studied by transmission electron microscopy. Single crystal disks 10 to 20 microns in diameter and thin enough for electron transmission were produced by ion etching suitably masked silver films grown epitaxially on sodium chloride. The disks, as-fabricated are in edge contact and model the geometry present in the early stages of sintering. Because heating of uncontaminated arrays in the high vacuum of the microscope specimen chamber resulted in severe evaporation, sintering was carried out in a static hydrogen atmosphere where material loss can be kept to a minimum. Electron microscopy of the neck regions between disks before and after heating shows that a build up of dislocation structure has occurred during sintering. This is taken as direct proof that dislocations are generated by surface tension forces early in the sintering process.
01 Aug 1973