Solid state electronics is the most rapidly advancing technology and requires wide spread knowledges in science, technology, and social, economic and polytical sciences to make the R & D investment the most efficient. This necessitates the closest communications and coopera-tion of large numbers of research and development groups in various institutions, private companies, and societies from basic researchers to service engineers as well as from material researchers to systems engineers. Unfortunately, Japanese society is not well organized for the need, resulting in inefficient R & D activities. This paper will discuss these problems, and present how important and urgent to the advancement of Japanese solid state electronics of solving these problems, by presenting few current topics in solid state electronics such as electroluminescence devices, glass semiconductor devices and bulk effect functional devices.
In this paper the preparation of evaporated E. L films of ZnS; Cu, Mn, CI phosphor was reported and the optical and electrical properties as well as the waveforms of the emitted light waves was compared for both thin films and thick films. The electroluminescent brightness follows the equation B=B0exp(-b/√V) over a certain range of alternating voltage, but its dependence with voltage was different in thin and thick films. In thin films the electrolumi-nescent brightness changed remarkably with the direction of the applied voltage but not so in thick films. The brightness and waveforms in thick films mainly depend on voltage where as in thin films they depend on current. The brightness waves of Al-SiO-ZnO cell in which SiO was inserted between the Al electrode and the ZnS film was similar to those of thick films on the voltage dependence, so in thick films an insulation layer, which seems to play a role in the excitation mechanism of E. L, appears to be formed between the Al electrode and the ZnS film.
It is known that spot focussed ultrasonic waves are sensitive to the internal irregularity of metals. Using these waves, a study was made on the relation between ultrasonic penetration and anisotropy of texture. As a result, we found that ultrasonic penetration changes when an inclined sheet of the specimen comprising the texture is rotated about an axis perpendicular to the surface. This phenomenon may be attributed to the elastic anisotropy of the texture. It appears, therefore in highly anisotropic metals such as copper or brass, but not in aluminium or an isotropic sample.
The changes in film temperature during the vapor deposition were measured directly by making use of a thin film thermocouple deposited on mica substrate. It is shown that, in the initial stage of film growth, films such as of Au, Ag, Cu show a rise in film temperature to a maximum value and after assuming the peak it maintains an almost constant value. The film thickness at which the temperature takes its maximum value is almost independent of deposition rate. As regard such changes in temperature, the effective increase of emissivity of films and metallurgical changes in the structure during deposition are an important factor in determining the rise in film temperature. From the measurment of emissivity, the rise in film temperature was also analyzed under certain assumptions and compared with experimental results.
The correlation between the red component of thermoluminescence and the red-Cu lumines-cence center in Cu-activated ZnS phosphors was investigated. The red component peaks of thermoluminescence were observed at about 120°K, 140°K and 190°K. Thermoluminescence spectra at each peak temperature was composed of 640 μm and 680 μm, emission bands. The mechanism in charge transfer involved in thermoluminescence is discussed on the basis of the above results, the thermal quenching of electron spin resonance signal for red-Cu luminescence center and the emission spectra.
Nickel-chromium films of various compositions were deposited on glass substrates by electron beam evaporation of the alloy nickrome with a bulk composition: Ni 80%-Cr 20%. The nickel chromium ratio of the deposited films was determined by X-ray fluorescence analysis. The resistivity and temperature coefficient of resistance were measured as a function of film composition, film thickness and deposition rate. The resistivity and temperature coefficient were nearly constant unless the nichel content in the films exceeded 60%, and changed remakably above a nickel content of 60%. The change of electrical properties in films seems to be due to some nature of the transition metals such as nickel and chromium.