Si nanowires (SiNWs) were synthesized by gold (Au)-catalyzed chemical vapor deposition (CVD). To control the morphology of SiNWs, the growth parameters were systematically changed and they were studied by transmission and scanning electron microscopes and Raman spectroscopy. We found that the shape of SiNWs is strongly affected by the growth rate, which could be controlled by the total pressure. The analysis of Fano-type spectral shape of boron (B)-doped SiNWs revealed that at least as high as 10¹⁹ cm^-3 active B atoms can be doped in situ during the growth. By using SiNWs as channels, back gate type field effect transistors (FETs) were fabricated on p-type silicon wafers. The best performance (I_ON/I_OFF>10⁷, S∼1 V/dec, V_th∼ -1 V, a hysteresis∼2 V, and mobility∼200 cm²/Vs) was obtained for SiNWs with core-shell structures. These performances are better than those of poly-Si thin film transistors.

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  Metal nanowire formation and annihilation are controlled using a solid electrochemical reaction simply by applying a bias voltage to an ionic conductor, such as Ag₂S and Cu₂S. This controlled formation and annihilation of a metal nanowire can be achieved both on the surface of the ionic conductor and inside of the ionic conductor, by placing a counter electrode with a gap and without a gap between the ionic conductor, respectively. A new type of a nanodevice called “Atomic Switch” has been developed using the controlled formation and annihilation of a nanowire. It shows novel characteristics, such as easy operation, simple structure, low power consumption. Recent development of an atomic switch using a metal oxide enables to integrate it with CMOS devices.

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  The current definition of the meter has been based on ‘the speed of light’ since 1983. Length standard measurements are performed using laser interferometers and are generally conducted in air. Specifically, a long length (referred to as “distance”) is measured in air. The accuracy of distance measurements in air is limited by the refractivity of air, which can be determined with an accuracy of only approximately 10^-8. For smaller uncertainties, we must measure distances in vacuum. For example, both laser strain meters, which are used for tectonic measurements, and laser interferometer gravitational wave detectors employ long-baseline interferometers in vacuum. Since the sensitivity of gravitational wave detectors become worse by residual gases in vacuum, a pressure of less than 10^-5 Pa is required for laser beam paths in the interferometer.

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  Because diamond has extremely superior characteristics in many physical properties and device performance indices compared with main current semiconductor materials, it is highly expected as “an ultimate semiconductor material.” Diamond is an ever-evolving material for semiconductor production, and this fact is supported by the technology for synthesizing high quality diamond called the chemical vapor deposition (CVD) method. Till now, various specific techniques have been proposed and used to implement the CVD method. Recently, the microwave plasma CVD method has been becoming standard. As demonstrated by the history of the production of semiconductor materials such as silicon, diamond synthesis requires not only an increase in the crystalline quality of produced diamond but also the production of large size diamond crystals. These efforts are accelerating in the world, but, on the other hand, a breakthrough or significant advance in the development in diamond synthesis technologies is required. In other words, the microwave plasma-assisted CVD method is now becoming a standard technique for diamond synthesis, but one of the important aspects in future diamond research includes determining whether this method can be a perfect final approach for synthesizing large diamond crystals quickly and effectively.
  This paper discusses the characteristics of diamond when used as a semiconductor device substrate, together with the microwave plasma-assisted CVD method which is currently one of the representative diamond synthesis methods. Also this paper describes the cathodoluminescence method usually used to evaluate synthetically produced diamond.

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  Structure and properties of indium tin oxide (ITO) films deposited by pulsed dc magnetron sputtering with or without inductively coupled rf plasma assist have been investigated for various O₂/(Ar+O₂) flow ratios. With inductively coupled rf-plasma assisted, (1) crystallinity of ITO films becomes high and (2) resistivity of ITO films decreases, in particular, for rf power of 150 W. Relationship between carrier concentration, n, and hall mobility, μ, is satisfied with the relationship of μ∝n^-2/3 for ITO films deposited by pulsed dc sputtering without rf-plasma. Hall mobility of ITO films deposited by rf-plasma-assisted pulsed dc sputtering hardly decrease as carrier concentration increases in comparison with relationship of μ∝n^-2/3. Lattice scattering of carrier electron is decreased by high crystallinity of ITO film deposited by pulsed dc sputtering with rf-plasma. In addition, scattering of carrier electron is decreased at grain boundary due to high packed density of ITO films deposited by rf-plasma-assisted pulsed dc sputtering. Increase of carrier density hardly causes the decrease of hall mobility. It is presumed that ITO film with high cystallinity results from the enhancement in the energy transferred to the surface of a growing film due to the increase in ion fraction and ion energy in the combination of pulsed dc and inductively coupled rf discharges.

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  Characteristics of the plume plasma produced by UV (λ=308 nm) laser ablation of a hot-pressed hexaganol boron nitride (h-BN) target have been investigated in a high vacuum at a laser power density ranging from 0.1 to 3.2×10⁸ W/cm². Time-resolved detection of the ablated species has been achieved by using a quadrupole mass spectrometer and an ion probe. The average kinetic energy of ablated B⁺ is much larger than that of B, and increases with an increase in the laser power density, whereas the acceleration of neutral B is limited. The ionization degree in the plasma varies from 0.1 to 15% with increasing laser power density. The angular distributions of the ion flux and the total particle flux can be fitted by a cosine or a bicosine function and strongly depend on the laser power density.

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