Showing papers on "Transmission electron microscopy published in 1971"
TL;DR: In this paper, the defect structure of high purity crystals of tungsten oxides with compositions between WO300 and WO299 has been investigated by transmission electron microscopy The oxygen deficiency appears to be accommodated by Wadsley defects, disordered crystallographic shear planes, parallel to {120}R (R = ReO3-type parent lattice) the planes tend to collect into bands which cause some regions of the crystal to have compositions far removed from the bulk
85 citations
82 citations
TL;DR: Si and Ge layers have been grown on (111) Si substrates by sublimation or evaporation in UHV as discussed by the authors, and the substrate temperatures ranged from 750 to 1000°C, and deposition rates up to 3 A sec-1.
68 citations
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39 citations
TL;DR: In this article, the phase decomposition inside the miscibility gap was investigated by transmission electron microscopy and by X-ray diffraction, and the first observable changes on aging at 500°C were appearance of side bands on X ray diffraction photographs of powder samples and of a periodic structure under the electron microscope.
Abstract: A miscibility gap exists in the spinel-structured region of the pseudobinary CoFe2O4-CO3O4 system in air. Phase decomposition inside the miscibility gap was investigated by transmission electron microscopy and by X-ray diffraction. In samples containing 35 and 50 cation % Fe, the first observable changes on aging at 500°C were appearance of side bands on X-ray diffraction photographs of powder samples and of a periodic structure under the electron microscope. When specimens which contained 50 cation % Fe were aged at 700°C, the first observed change was another set of diffraction lines; homogeneously distributed fine particles were also observed. The former behavior was attributed to spinodal decomposition and the latter to classical nucleation and growth.
37 citations
TL;DR: In this article, a study of the growth of tellurium thin films was made on three different substrate materials, namely, 7059 alkali free glass, single crystal potassium bromide and single crystal calcium fluoride.
31 citations
TL;DR: In this paper, a transmission electron microscopy and diffraction study of the homologous series of oxides TinO2n-1 (4≤n≤10) reveals that the structures of these oxides are derived from rutile by regular crystallographic shear on planes parallel to (121), as previously suggested by Andersson and Jahnberg (Arkiv Kemi).
Abstract: Transmission electron microscopy and diffraction study of the homologous series of oxides TinO2n-1 (4≤n≤10) reveals that the structures of these oxides are derived from rutile by regular crystallographic shear on planes parallel to (121), as previously suggested by Andersson and Jahnberg (Arkiv Kemi. 21 (1963) 413). Electron microscope images clearly show microstructures. Micro-twin structures of fine scale are observed very often for specimens with n≥7 but never detected when n≤6. The interface plane of the twin bands is parallel to the (200)r in most cases, although the twin structure with the interface plane (002)r or (020)r is seen occasionally. A mode of two phase mixture for the specimen in the two phase region is clarified.
24 citations
TL;DR: In the transmission electron microscope, as shown in figure 1 (Nixon 1962), the electron gun at the top illuminates the specimen with the beam angle controlled by the condenser lens as mentioned in this paper, which is used to magnify the image of the specimen which is viewed on the final screen at many thousand times magnification.
Abstract: In the transmission electron microscope, as shown in figure 1 (Nixon 1962), the electron gun at the top illuminates the specimen with the beam angle controlled by the condenser lens. The lenses below the specimen are used to magnify the image of the specimen which is viewed on the final screen at many thousand times magnification. If a second electron gun is placed below the fluorescent screen at the bottom of the column and the electron beam is projected upwards through the same lenses this second electron source will be reduced in size by the same amount that the specimen image is magnified. This effect can be observed with both electron guns on at the same time and demonstrates the reversibility of rays through electron lens systems. In this way the resolved point in the specimen image on the fluorescent screen or on the photographic plate is equal to the focused electron probe in the plane of the specimen.
21 citations
20 citations
TL;DR: In this paper, the absence of dark field images indicates that an amorphous state has been formed where areas of atomic order are ⩽ 20 A in diameter and the unaccounted volume increase of 2.4% which occurs in U 3 Si irradiated under similar conditions might be explained in terms of vacancy clusters, a size that is less than can be resolved by the microscope technique used.
TL;DR: In this paper, it was found that dislocation loop structures were evolved in the case of low dose irradiations where there was only a small degree of overlap of adjacent disordered zones in the as irradiated state.
Abstract: The nature of damage present in ion implanted silicon crystals has been observed by transmission electron microscopy for a wide range of ion species (A, Xe, Pd, Au, Si, Ge, at 40–100 keV) over the dose range 1013 to 1017 ions/cm2 so that the marked dose dependence of defects after annealing (up to 900°C)and special impurity effects could be investigated. Electrical measurements (sheet resistivity and Hall effect) have been made on antimony doped p-n junction structures irradiated with non-doping ions to support these observations and determine some electrical effects of the damage. It was found that dislocation loop structures were evolved in the case of annealed low dose irradiations where there was only a small degree of overlap of adjacent disordered zones in the as irradiated state. For irradiations which created a complete surface amorphous film, the damage remaining after 650°C anneals consisted of a compIex dislocation array with microtwins, planar defects, and often some polycrystallinity...
TL;DR: In this article, the 6H-polytype of silicon carbide has been studied by means of transmission electron microscopy and diffraction, and the displacement vector was deduced from contrast and extinction criteria to be of the type 16 〈2201〉.
TL;DR: In this paper, the twin boundary-grain boundary intersections in thin foils have been combined in a simultaneous measurement of absolute (average) interfacial free energies in 80 20 NiCr (Chromel-A) at 1060 °C.
TL;DR: In this article, electron microscopy of thin PbTe films was performed on the cleavage face of NaCl with substrate temperatures of 100 and 300 °C and deposition rates of approximately 100 and 1000 A/min, respectively.
Abstract: Epitaxial thin films of PbTe have been prepared by vacuum evaporation onto the (001) cleavage face of NaCl with substrate temperatures of 100 and 300 °C and deposition rates of approximately 100 and 1000 A/min, respectively. Electron diffraction showed the films to be strongly oriented with the (001) planes of the deposit parallel to the substrate. Transmission electron microscopy of thinner films, ≈ 0.2μ thick, showed no significant variation in microstructure with changes in substrate temperature and deposition rate. Such films showed a high density of dislocations, ≈ 5×1010/cm2, the majority of which ran normal to the plane of the film. Many were arranged in low‐angle grain boundaries, the most prominent microstructural feature of the films. These exhibited rotations up to about 2° and the average boundary spacing for these thin samples was estimated at 2000 A. Surface replication of a number of films grown with comparable conditions but varying thicknesses show features that could be indicative of int...
TL;DR: In this article, a method for obtaining atomically smooth (111)oriented single-crystal films of Ag on specially prepared ( 111) monocrystalline NaCl films has been developed.
Abstract: A method for obtaining atomically smooth (111)‐oriented single‐crystal films of Ag on specially prepared (111) monocrystalline NaCl films has been developed. The latter, approximately 100 A thick, were prepared by vacuum deposition onto air‐cleaved mica at 25 °C in pressures of around 10−6 Torr. Ag films deposited on these NaCl films at 270 °C were (111)‐oriented monocrystals with atomically smooth surfaces that compared well with those formed directly onto heated mica. The Ag/NaCl/mica films can be removed easily from their substrates for subsequent transmission electron microscopy by dissolving the intermediate layer in water.
TL;DR: In this paper, the most successful results for optical and transmission electron microscopy of titanium and titanium alloys are described; a special etching procedure is described for revealing grain sizes of the order of 1 micron.
01 Jan 1971
TL;DR: In this article, the phase transformation to the rhombohedral samarium-type structure was studied in Gd-Ce alloys and the experimental techniques used were electrical resistance measurements, elevated-temperature X-ray diffraction studies, optical metallography, and transmission electron microscopy.
Abstract: The nature of the phase transformation to the rhombohedral samarium-type structure was studied in Gd-Ce alloys. The experimental techniques used were electrical resistance measurements, elevated-temperature X-ray diffraction studies, optical metallography, and transmission electron microscopy. Electrical resistance-temperature hysteresis loops were observed in two temperature regions. X-ray studies confirmed that the upper temperature behavior was due to the phase transformation (hcp ⇌ Sm-type or dhcp ⇌ Sm-type). The lower temperature hysteresis loop does not involve a change in crystal symmetry but does coincide with an increased rate in expansion of thea0 parameter such that the axial ratio becomes essentially constant with temperature. Optical and electron microscopy revealed a morphology of fine parallel bands extending across a grain in a single variant. This is consistent with the transformation plane being the basal plane.
TL;DR: The effect of α-particle irradiation (55 MeV, total dose ∼1015 particles/cm2) on the microstructure of ThO2 was studied by transmission electron microscopy.
Abstract: The effect of α-particle irradiation (55 MeV, total dose ∼1015 particles/cm2) on the microstructure of ThO2 was studied by transmission electron microscopy The only as-irradiated damage seen consisted of point defect agglomerations visible as small black spots Subsequent heating to ∼1500°C in the electron microscope caused the spots to grow into loops 50 to 200 A in diameter, but no voids, bubbles, or pores were observed The preferred loop planes were {311}, {110}, and {012}, in that order of frequency
TL;DR: In this article, the fracture surfaces of a fine grained isotopic graphite were examined using two stage plastic carbon replicas and scanning electron microscopy, and large numbers of groups of microcracks were seen in the thin foil, which were shown to occur in the basal plane.
Journal Article•
TL;DR: In this article, the cubic phase generally coexisted in a small amount in films and showed epitaxial orientation, including {111} microtwins, on all substrates, but no appreciable change of the amount of cubic phase was observed on these substrates.
TL;DR: The early stages of crystallisation in a Li2O-SiO2-P2O5 glass were studied by transmission electron microscopy using thin sections prepared from the bulk material by chemical thinning as discussed by the authors.
Abstract: The early stages of crystallisation in a Li2O-SiO2-P2O5 glass were studied by transmission electron microscopy using thin sections prepared from the bulk material by chemical thinning. Small crystalline regions of lithium disilicate were formed, often as several small single crystals joined together around a central core. Possible explanations of the core are discussed in terms of a region of different chemical composition or a central region of disorder. The observations are also compared with the growth of crystal spherulites in polymers.
TL;DR: In this article, the body-centred rhombohedral symmetry of the MnAl(r) phase was investigated by both X-ray powder method and transmission electron microscopy, and the unit cell was concluded to have "body-centered RHombohedral" symmetry, with lattice constants of a=8.96 A and α=89° 1' when the alloy has composition of 43 at. per cent of manganese.
Abstract: MnAl(r) phase is investigated by both X-ray powder method and transmission electron microscopy. The unit cell is concluded to have "body-centred rhombohedral" symmetry, with lattice constants of a=8.96 A and α=89° 1' when the alloy has composition of 43 at. per cent of manganese. Single crystalline electron diffraction patterns also assure this unit cell. Surface etching patterns of the alloy, which often look like arrow feathered patterns, are also observed on transmission electron micrographs. The micro-structure can be interpreted on the basis of above cell and a model of configuration of the subgrains is proposed, boundaries of which, shafts and barbs, are indexed as {100} and {110} respectively.
TL;DR: In this article, the authors demonstrated localized effects on the emission close to twin boundaries and stacking faults in the as-grown crystals, which may be interpreted in terms of changes in band gap at the defect.
Abstract: Defects in wurtzite single crystals of ZnS, ZnSe and CdS have been observed by means of both scanning and transmission electron microscopy. Application of the scanning technique to the observation of cathodoluminescence in these materials has demonstrated localized effects on the emission close to twin boundaries and stacking faults in the as-grown crystals, which may be interpreted in terms of changes in band gap at the defect. This method has also been applied to heavy ion bombarded crystals; in addition, transmission electron microscope studies have been made of these irradiated samples and the annealing behaviour of the radiation damage has been observed. Finally, in-situ optical absorption experiments have been carried out on samples irradiated at liquid nitrogen temperature, and effects on the characteristic exciton absorption have been noted.
TL;DR: In this paper, the effect of chromatic aberration on the resolution of an electron microscope image has been investigated using a model specimen of an unstained biological material with a variation in mass thickness.
Abstract: On the assumption that inelastic electron scattering in a specimen is localized and gives rise to an incoherent beam, an estimate is made of the effect of chromatic aberration on an electron microscope image. A model specimen of an unstained biological material with a variation in mass thickness is used to calculate the incoherent inelastic image; the aberration function is applied to this image to give an image with spherical and chromatic aberration defects. From this procedure, an estimate is made of the loss in resolution for the inelastic image due to chromatic aberration for two specimens of very different mass thickness (40 and 200 mg m−2 of carbonaceous materials) and for objective aperture sizes corresponding to semi-angles of 00025, 0005 and 001 rad (incident electron energy 100 keV). It is concluded that chromatic aberration results in a loss in resolution on a 5-10 A scale within the approximations of this work. The deterioration in resolution due to chromatic aberration is not very dependent on the size of the objective aperture. The conclusions of the present work are consistent with recent experimental work on the effect of chromatic aberration on the electron microscope image.
TL;DR: In this article, the influence of substrate temperature and deposition rate on GaSe thin film structure was investigated, and it was found that the lateral crystallite size increased from 250 A to 5000 A, and at 220 °C large single crystals were formed in the film.