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Fine particles of the In-Sb system were prepared by the FGE technique (flowing-gas evaporation technique). The characteristic of the technique is that the formation of the vapor zone and particle growth zone along the flow of inert gas can be controlled by the inert-gas species and the flow velocity. From single-source evaporations, In fine islands grown on the amorphous carbon in the metal vapor zone showed a fiber structure with [111] and [001] fiber axes. In the particle growth zone In fine particles were formed, showing very frequently a characteristic contrast in them due to a lattice defect. Sb fine particles showed amorphous structure. These results may be attributed to the enhanced quenching effect of the FGE technique, already observed in the ordinary gas-evaporation technique. By coevaporation of In and Sb, granular film grew in the metal vapor zone, and fine particles were formed in the particle growth zone. The crystal structure was assigned to be the zincblende type including the wurtzite type of intermetallic compound InSb.

Aluminum cluster ions Al+n are generated by a liquid metal ion source and observed up to n=10 using a magnetic mass analyzer. Relative integrated intensities of cluster ions as a function of n show a distinct step between n=7 and 8, which is explained by the electronic shell model. Cluster ions have lower kinetic energy compared with monomer ions which are accelerated to the full energy. Moreover, energy spread of cluster ions is larger than that of monomer ions. These results are attributed to the difference of ion formation mechanism. In addition to the fully accelerated monomer ions, at a high ion current region there also appear monomer ions with energy deficit which are formed in the same process as cluster ions.

Atomic clusters and nm-sized metal crystallites embedded in metal-MgO composite films are observed by using off-axial imaging conditions in 1 MV high-voltage electron microscopy. Details of the observations of gold, lead and iron clusters and crystallites are reported and the relationship between the existing state of the clusters and the physical properties of the composite films, including conductivity, magnetic and optical properties, is discussed.

Crystallography characteristic of fine particles prepared by the gas evaporation technique is described. The crystal habits observed for fcc and bcc metals, truncated octahedron and truncated rhombic dodecahedron, respectively, are explained by a requirement of the surface energy minimum, that is, Wulff polyhedron. Characteristic crystal structures caused by the small size for fcc and bcc metals are shown as multiply twinned particles and A15 structure, respectively. Multiply twinned particles observed for Wurzite type of structure such as GaN, AIN, CdS are also mentionned. Finally, crystal structures and habits of fine particles accompanying the phase transformation during the growth are described for Ti, Be, Fe and Mn particles.

Thin films of Al-Mn, Al-Fe and Al-Cu-Fe quasicrystalline films are prepared by a successive deposition technique in a vacuum onto air-cleaved sodium chloride surfaces at substrate temperatures of 220–350°C. The growth of the quasicrystals is found as grains of 20–50 nm in size, the five-fold axis being perpendicular to the film surface and the two-fold axis of the quasicrystal parallel to [110] directions of the (111) orientated aluminum film. For the Al-Fe and Al-Cu-Fe system, the rotation of the five-fold axis around the two-fold axes by around 10° can be recognized. Below about 10 at % of manganese or iron content, a coexistence of aluminum and the quasicrystalline grains is observed. High resolution electron microscopy is applied to the quasicrystal films, by which the vertex model with a decoration in Penrose tiling is suggested.

Single crystalline composite films of metals and magnesium oxide (MgO) are prepared by a simultaneous deposition technique and analyzed by electron microscopy. The composite films are found to be composed of epitaxially grown metal crystallites a few nm in size and atomic clusters in MgO single crystals. The growth mechanism is interpreted in a manner similar to that in ordinary vacuum-deposited films, the small difference being the sharp size-distribution due to the co-existence of metal and MgO vapors. The specific resistivity of the films is also measured and analyzed in relation to the discontinuous structures of nm-sized metal crystallites in MgO crystals.

Single crystalline composite films of Au-MoS2 and CaF2-MgO, in which fine crystallites of Au and CaF2 with diameter less than about 20 nm are embedded in MoS2 and MgO, respectively, are prepared by the simultaneous vacuum deposition technique, and characterized by high resolution electron microscopy.

Magnetic property of single crystalline iron-MgO composite films was measured with a SQUID magnetometer. The thermo-magnetic (M-T) curves showed splitting of the magnetization in low temperature, depending on zero-field cooling and field cooling cases. The magnetization (M-H) curves at 5 K after the zero-field cooling showed hysteresis with larger coercive force than that of bulky iron. Systematic study of the relationship between the structure of the composite films and the magnetic property showed that nm-sized iron crystallites embedded epitaxially in MgO films play a main role to the property.

Optical emission and absorption spectra from a growth zone in Cu smoke were measured by using a quartz prism spectrograph and a single-grating spectrophotometer. Atomic lines of Cu, band systems of Cu2 were observed. Two new band systems with 0–0 band heads at 252.88 and 238.79 nm were found. The continuous spectra due to Rayleigh scattering by fine particles were also observed. Variations of density of various species as a function of vertical position were revealed.

Single crystalline composite films of Au-MoS2 and CaF2-MgO, in which fine crystallites of Au and CaF2 with diameter less than about 20 nm are embedded in MoS2 and MgO, respectively, are prepared by the simultaneous vacuum deposition technique, and characterized by high resolution electron microscopy.

A growth of nm-size γ-iron crystallites was found in iron/magnesium oxide (MgO) composite films prepared at 350°C in a simultaneous vacuum-deposition. The relationship between the grwoth condition and structures was systematically studied. The γ-iron crystallites with a thickness of 1−2 nm epitaxially embedded in a MgO single crystal film were found to transform into α-iron ones with increasing the thickness. The thermo-magnetic curves and the electron energy loss spectra of the composite films suggested that the γ-iron crystallites had a high-spin magnetic state similar to that in α-iron crystallites in MgO films previously reported

Recent progress of transmission electron microscope(TEM) enables us to perform electron diffraction from nm-sized areas(nano-diffraction) with a good correspondence with HREM. Nano-diffraction is useful for obtaining local structural information. One of the present authors (NT) applied the method to interfaces of GaAs/AlGaAs superlattices for detection of compositional variation of aluminum(Al) and to nm-sized γ-iron crystallites in MgO for analysis of the strain. Although nano-diffraction has been performed successfully in STEM instruments by Cowley and others, the method in TEM has an advantage in a good compatibility with the structure-imaging method and the established bright and dark-field(BF & DF) imaging methods. In the present paper we report for the first time the detection of lattice strain around interfaces of InP/InGaP strained superlattices as well as results of GaAs/InGaAs, GaAs/AlGaAs and Ge/Si superlattices by using the TEM nano-diffraction method.The nano-diffraction was performed with 200 kV transmission electron microscopes of Cs = 1.2 mm(JEM-2000FX) and Cs = 0.5mm(JEM-2010L Before focusing an election probe, HREM and DF images of the interfaces were taken in the [100] zone axis at 100-400 k in direct magnification.

Isolated amorphous Sb particles are used to obtain information on the crystallization of nanometer-sized particles. The postannealing was carried out between 110 and 150°C for 10 to 90 min and the crystallization ratio was measured by the dark field electron microscopic observation. The activation energy for crystallization shows a particle-size dependence, that is, it increases from 1.85 to 2.01 eV with the decrease in diameter from 30 to 10 nm. The size dependence is discussed in relation to the hydrostatic pressure effect induced by the small surface curvature of the particles.

Lattice bending around the interfaces of strained InP/InGaP/InP superlattices was analyzed by using thickness fringes in the dark-field electron microscopy and nanometer-area electron diffraction patterns. The present paper is complementary to a previous paper about strain detection by using thickness fringes in the bright-field electron microscopy (Jpn. J. Appl. Phys. 30 (1991) L52). By using the two methods, lattice bending around the interfaces of the superlattices with a lattice misfit of 1% was quantitatively evaluated in a three-dimensional form. Comparison between the methods and the usual lattice-imaging method in high-resolution electron microscopy(HREM) is discussed.

A new method for analyzing semiconductor superlattices such as GaAs/Ga 1−x Al 1 is reported: An electron probe of 1–2 nm in size formed in a transmission electron microscope is incident in the [001] direction on a {110} cleaved crystal of the superlattices and scanned around the interfaces in the cross-sectional observation. The nanometer-area diffraction patterns are recorded continuously while scanning the probe. Using this method, the structural and compositional information can be obtained from nanometer-areas in the superlattices by comparing the actual diffraction patterns with the simulated ones.

The structure of PbS layers around 1 nm thick grown on various single-crystal substrates is studied by using high resolution electron microscopy. The substrates used are cleaved NaCl(001) surfaces, BeO films with (00.1) fibre orientation, vacuum-deposited PbTe(001) films, Mg(00.1) plates prepared by the gas evaporation technique and vacuum-deposited Au(111) and Au(001) films. Two kinds of modified structure characteristic of the low thickness are found on NaCl and PbTe. On BeO films, an image reflecting the atomic stacking for PbS islands with three atomic heights and an image of a lead atom chain are obtained. Images interpreted as a lead monolayer are obtained on NaCl and Mg(00.1). An adsorption structure with a new arrangement close to a 4 × 1 structure is found on Mg(00.1) and determination of the adsorption site of the lead atoms is attempted by computer simulation. On Au(111) and Au(001), only diffraction patterns suggesting the growth of a lead monolayer are obtained.

Fine particles of silicon and germanium were prepared by evaporation in argon gas at low pressures, and they were studied by electron microscopy. Relatively large particles showed distinct crystal habits for both materials. A typical habit of silicon was an polyhedron bounded by twenty four {311} and eight {111} faces, and that of germanium, an icositetrahedron bounded by {311} faces. Crystallites with these habits have the diamond structure as usual. However, relatively small germanium particles, which were formed in the inner part of the smoke, showed no distinct habit and had an unknown structure with a tetragonal unit cell, a=5.37 A and c=9.04 A.

Thin films of Al-Mn quasi-crystals are prepared by a successive deposition technique in vacuum onto air-cleaved sodium chloride surfaces. At a substrate temperature of 280 to 330°C, the growth of the quasi-crystals is found to produce polycrystalline films with a grain size of 20 to 50 nm, the composition ratio of aluminium and manganese being about 5:1. No structure change can be found after a heat treatment of the film at 280°C for 8 h, though a trend of grain growth is detected. For a specimen with a composition ratio above 8:1 grown at 280°C, a diffraction pattern due to aluminium with (111) orientation is recognized in addition to that of quasi-crystals, the lattice relation being that the [110] direction of aluminium is parallel to the two-fold axis of the quasi-crystal. A heat treatment at 330°C for a few hours brings about a transformation from quasi-crystalline films to an alloy phase, Al6Mn. High resolution electron microscopy is applied to the quasi-crystal films and the edge length of the fundamental hexahedron of the Penrose tiling has been determined to be 0.47 nm from the structure images.

The structures of Guinier-Preston, G.P., zones and the θ‘-phase are studied by means of high resolution electron microscopy including the lattice image technique. G.P. zones can be observed mainly as black lines in the bright field, but sometimes white lines, depending on the diffraction condition. the θ’-phase appears as black lines aligned in parallel with about 8 A separation, but a different separation can also be recognized. In lattice images, the relative positions of lattice fringes around precipitates which are observed as white lines are measured. The result shows an existence of an asymmetric strain field around the G.P. zones.

The use of evaporated BeO films as specimen supporting films for high resolution electron microscopy is described and it is shown that they are superior to evaporated carbon films. In both the bright and dark field images, the BeO films are perfectly free from noise such as that characteristic of carbon films. Gold particles as small as 7 A in diameter which could not be observed with carbon films become observable with the BeO films. BeO films have the advantage that the specimen can be fixed tightly to them by the extraction technique.

Fine particles of several kinds of bcc metals were prepared by evaporation in an argon atmosphere. They were collected at various growth zones in the smokes and their structures and habits were studied by electron microscopy. Vanadium and iron particles grown in all zones have the ordinary bcc structure. However, chromium and molybdenum particles grown in the inner part of the smokes have the bcc structure, and those in the outer part have the A-15 type structure. Habits of particles with the bcc structure can be generally described in terms of rhombic dodecahedra truncated by six (100) faces with various degrees of truncation from 0 to 100%. The truncated rhombic dodecahedron is a common habit to the bcc metals, though the degree of truncation is dependent on the metal. For vanadium it varies from zone to zone systematically. Molybdenum particles of rounded cube and {211} icositetrahedron are found to have the A-15 type structure in addition to the well known {211} icositetrahedron and rhombic dodecahedron found in chromium.

Composite films of metal-crystallites embedded in 001 and 110 single crystalline MgO films are prepared by the simultaneous vacuum deposition technique. The single crystalline nature is useful for electron microscopy and measurement of the physical properties. The epitaxially grown metal-crystallites of a few nm in size are analyzed by high resolution electron microscopy and micro-diffraction. The heat treatment of the as-grown composite films brings about change of the crystal habit for gold in MgO, grain-growth and phase-transformation for iron and formation of spinel for titanium. The specific resistivity and magnetic property are measured for gold - MgO and iron-MgO composite films to understand the relation between the structures and properties.

A large amount of extremely fine particles of Ag were prepared by vacuum evaporation onto a running oil substrate. The size distribution of Ag particles thus prepared was studied by electron microscopy. It was found that the mean diameter of the particles strongly depends upon the deposition rate, and kind and viscosity of the oil. Particles of mean dimater from 30 to 80 A can be produced. The sticking coefficient on the oil surface for arriving atoms is, in general, smaller than that on a glass surface. The coefficient increases with increasing viscosity for the same kind of oil. Coalescence growth of particles is also detected by heating the oil containing the particles. The heat treatment also enables us to control the practicle size between 30 to 80 A.

A new holographic method utilizing the time-reversal operation of an electron beam has been de- vised to observe separately electric and magnetic phase distributions as interference electron micrographs, which had been unavailable using conventional methods. By this technique, both the magnetization and thickness distributions of three-dimensional cobalt particles have been determined.

TiH2 particles with fcc structure can be produced in an atmosphere of reduced pressure of H2, instead of an ordinary inactive gas, by the gas evaporation technique. The habit of the particles grown in the intermediate zone of a smoke is determined by means of electron microscope to be dodecahedral and consists of 8 {111} and 4 {100}. As in the case of Ti particles, the growth mechanism can be considered as follows: The bcc TiH2 particles initially formed, the high temperature phase, are transformed into fcc structure, the low temperature phase, through the martensite transformation with a slight change of the habit, from the rhombic dodecahedral to simple dodecahedral. For the preparation of amorphous particles, first the quenching rate of a particle, dT/dt was estimated to be more than 104°C/s. The quenching rate was estimated from measurements of the temperature gradient around the evaporation source, dT/dx and the rising velocity of the particles along the convection flow of residual gas, dx/dt. The preparation of ultrafine particles of Pd80Si20 chosen as a test material was attempted. However, the particles showed crystalline rather than amorphous structure.

Holographic interference electron microscopy is presented for investigating the structure of domain walls in plate-shaped cobalt particles. Circular magnetic lines of force are directly observed as contour fringes which overlap individual particle micrographs. These fringes show at a glance how the spin rotates across domain walls. It is also suggested from holographic electron diffraction that the spin stands up in the center of the particle.

Composite films of magnesium oxide and metals (Au, Pd, Pb, Fe, Cr and Ti) are prepared by a simultaneous deposition technique. The mean thicknesses of magnesium oxide and metal are 20 to 25 nm and 1 to 3 nm, respectively. All metals except titanium grow epitaxially as small crystallites of a few nm in size inside single crystalline magnesium oxide films, the thickness of metal crystallites being estimated to be a few atomic layers. For iron-magnesium oxide composite films, the transformation from α-iron to γ-iron is observed by the heat treatment at 500°C for two hours. For titanium-magnesium oxide composite films, titanium grows as crystallites less than 1 nm in size with the structure of Ti1−xO.

Evaporation of iron at a reduced pressure varying from a few to 200 Torr of ammonia causes the growth of several kinds of fine particles of the Fe-N system. The particles thus prepared were studied by means of electron microscopy. At a few Torr of gas pressure, particles of α-Fe (bcc) and γ-Fe (fcc) show the truncated rhombic dodecahedron and mainly needle habits, respectively. The former is characteristic of bcc metals while the latter is a modification of the well-known pentagonal decahedron of multiply twinned particles. The lattice parameter of the γ-Fe is 3.64 ± 0.03 A, which corresponds to the nitrogen content of 2.5 wt%. Above 100 Torr of gas pressure, particles of γ′-Fe 4 N grow. The particles collected on carbon films in the inner and outer zones are sometimes aggregated in clusters.

Thin films of AlMn quasicrystals are prepared by a successive deposition technique in a vacuum onto air-cleaved sodium chloride surfaces at a substrate temperature of 280–330°C. The growth of the quasicrystals is found as random orientated films with a grain size of 20–50 nm for Al-21 at.% Mn. For a specimen of Al-5at.% Mn grown at 280°C, quasicrystals and aluminum with (111) orientation are recognized, the lattice relation being that the [110] direction of the aluminum is parallel to the twofold axis of the quasicrystal. Heat treatment at 330°C for a few hours brings about a transformation from quasicrystalline films to an equilibrium phase Al 6 Mn. High resolution electron microscopy is applied to the quasicrystal films, by which the edge length of the fundamental hexahedron of the Penrose tiling is determined to be 0.47 nm from the structural images.

NaCl(001)へき開面上および(110)硯磨面上にMgOと金属(Au,FeおよびTi)を同時蒸着をすることにより,単結晶薄膜中にエピタキシャル成長をした微結晶が一様に埋め込まれた複合膜を作成し,電子顕微鏡を用いて観察した。MgO-Au複合膜の場合,数nmの大きさのAu微結晶の厚さは高々数原子層であることがわかった。MgO-Fe複合膜の場合,Feは1nm見当の微結晶として成長し,500℃,数時間によりα-Fe鍬結晶の成長,また,1000℃ の熱処理により高温相であるγ-Fe微結晶が室温まで焼入れされることを見いだした。MgO-Ti複合膜の場合は前の二つの場合とは異なって,まず1nm以下の大きさの秩序空孔をもつTi1-xO微結晶として成長し,この試料の1000℃,数分間の熱処理によりMgO膜中にスピネル構造をもつMg2TiO4,微結晶の成長が認められた。

Composite films of metal crystallites embedded in magnesium oxide (001) and (001) single crystal films are prepared by the simultaneous vacuum deposition technique. The epitaxially grown metal crystallites with sizes of a few nm are analyzed. The growth features are also discussed.

Magnesium ultrafine particles have clear-cut habits such as hexagonal plates and polyhedra. When magnesium is evaporated downwards using a tube with holes at the bottom, hexagonal plates are formed exclusively throughout the smoke. Their size is controlled by selecting an inert gas. The growth process of an hexagonal plate can be considered to be a coalescent growth of other hexagonal plates.

In the first part of the experiment, the deposition rate, r (A/min), was changed systematically from about 10 A/min to 10 4 A/min. The epitaxial temperture was found about 150°C higher under the highest deposition rate than the lowest rate. The result was in accordance with the theory proposed by Walton. In the second part of the experiment, in which air- and vacuum-cleaved surfaces were used as substrates, the residual gas in the evaporation chamber was specified to N 2 , O 2 and H 2 O of about 10 -5 Torr. It was concluded that the epitaxial temperature was influenced only by partial pressure of water vapour, P H 2 O . By the combination of the above two results and the results obtained by Ino et al. in ultra high vacua, it is infered on empirical base that the epitaxial temperature depends upon the ratio P H 2 O / r .

AuCu alloy particles were prepared by the vacuum evaporation technique and studied by means of high resolution electron microscopy. The structure of alloy particles just after the deposition was, in general, the ordered structure, AuCu I, and the heat treatment was necessary to obtain AuCu II phase. The simultaneous evaporation technique was more favorable to grow AuCu II particles than the successive evaporation technique. With decreasing particle size, the formation of AuCu II phase turned out to be difficult, and for particles around 100 A in 200 A in diameter, only a portion of AuCu I particles transformed to AuCu II particles. For small AuCu II particles, the distortion of the antiphase domain boundaries and the lattice planes at the periphery of particles were observed through the dark field images the lattice images, besides a zigzag nature of the antiphase domain boundaries.

Techniques of low temperature specimen method for electron diffraction and electron microscopy were developed. Convenient low temperature specimen holders were constructed with a sufficient number of freedoms to adjust specimen settings for various observations. The temperature of specimen support could be varied within a range from liquid nitrogen temperature to +200°C. Contaminations of specimen caused by condensation of residual vapours, which usually occur considerably below -80°C, were practically eliminated by improving the vacuum of the apparatus and by the use of a special shield around specimen. Results of preliminary studies on ice and mercury were briefly described: For ice, the contribution of hydrogen atoms to the diffraction pattern of ice was recognized; for mercury, the solid-liquid phase transition was studied by electron diffraction and the growth of hair-like mercury crystallites was observed by electron microscopy.