Recent works on the observations of single atoms and molecules by conventional high resolution transmission electron microscopes have been introduced. It is emphasized that, for the visualization of atoms by using such microscopes, the improvement of the image cont-rast and preparation of new supporting film with small noises are necessary. It is discussed that the images of heavy atoms such as thorium supported on graphite thin films can be observed with some contrast in the dark field image with tilted illumination. Some theoretical profiles of the image of Th single atoms in bright and two kinds of dark fields images are shown. Some dark field elecron micrographs of Th single atoms in molecules and crystals are also shown together with their bright field images.
Sliding friction between a copper plate and a spherical slider (copper and steel) was studied in a vacuum and air. In the case of a vacuum, specimen surfaces were made clean by means of electron bombardment. The friction of hard sliders (steel and diamond) with various radii against the (100) plane of copper was also studied in air under various loads. Although friction between similar metals is entirely due to adhesion, the main cause of fric-tion between copper and steel is by adhesion only in the case where the surfaces are extre-mely clean, since friction in air is strongly influenced by the resistance due to the bulge formed in front of the slider. Anisotropy of friction is attributable to that of the surface deformation accompanying the sliding of a slider.
Influence of electron microscope gun geometries on the field distribution over a spherical cathode surface is estimated using the axial potential formula given by M. Ploke. Special attention is paid to the field in the immediate vicinity of the cathode surface. The emitting area and cut off bias voltage are analytically calculated including gun geometries. In order to obtain a sufficiently high brightness with a small emission current, it is found that a gun arrangement functions more efficiently, 1) the smaller the cathode height, 2) the larger the Wehnelt diameter in the case of a positive cathode height, 3) the smaller the Wehnelt diameter in the case of a negative cathode height (with the cathode protruding from the Wehnelt aperture), 4) the smaller the Wehnelt-anode distance, 5) the smaller the radius of the cathode sphere. In cases of 1), 2) and 4), there exists a suitable compromise from the viewpoint of insulating problems of the bias circuit. This conclusion is also experimentally confirmed. Furthermore, a design example is given to illustrate the use of calculated results.
A coaxial sputtering system is modified to be able to deposit three layers of film on 57 sub-strates of 60mm × 100mm dimensions. In order to get a better film uniformity, targets have coaxial surfaces with a substrate holder, and special shields are assembled in front of the targets. Space potentials at 1cm in front of the substrates, are measured by using a Langmuir type probe. The potential is -2_??_-3 V when the substrates are made of metal or glass (see Fig. 7). The Effect of target voltages and currents on the probe potentials is measured, and the relation between specific resistivities of tuntalum films sputtered by the system and probe potentials is investigated. It is assumed that if bias sputtering is done by the present system, better uniformities of sheet resistance of tantalum films will be obtained. Bias voltages are applied to the substrate holder, and uniformities of sheet resistances of tantalum films are investigated. The best uniformity is obtained when the substrate bias voltage is +10V (referred to earth potential). It is found that 82.5% of all sheets show variation of sheet resistance of less than ±3% and no sheet shows a variation of more than ±5% (see Table 2).
Photon drag voltage for a sample of p-type germanium has been measured experi-mentally over a wide range of light intensity from 20kW/cm2 to 100MW/cm2 by the use of TEA-CO2 Laser at 10.6 μm. The measu-red value of responsivity was found to be 0.72×10-7 Volt cm/(Watt Ohm) at 50kW/cm2. There was some evidence of a nonli-near dependence for Photon drag voltage on input light intensity.
Conditions of Ion beam scanning are discus-sed to obtain a required uniformity in ion density on a target. It was found that the number of scanning lines could be reduced by the use of ion beams of the cosine curve or the normal distribution curve, out of the many distribution models tried. A method of measuring the uniformity in ion density is also given, and experimental results are presented.