A novel synthesis of high density aligned carbon nanotubes in the liquid-phase has been demonstrated. Carbon nanotubes have been grown on Si substrate in methanol, and other alcohols by using Fe catalyst. Hollow multiwall carbon nanotubes external diameters ranging from 6 to 26nm standing well on the Si substrate were obtained. The growth rate of carbon nanotubes was∼several microns per minutes. The large difference in temperature between the substrate surface and the liquid can cause very high nucleation density and high growth rate and affect the growth direction of the carbon nanotubes. Very few amorphous components was produced among the carbon nanotubes because reaction proceed only on the hot substrate and no reaction can proceed in the liquid phase. This simple method can promise to give a large scale production of the carbon nanotubes.
Electrolytic production of Zn-Al2O3 composite coatings was tried in sulfate solutions containing Zn2+ and Al3+ ions by codepositing Al3+-compound formed due to pH rise in the cathode layer. The results obtained are as follows: (1) The Zn-Al oxide composite was obtained under the conditions that hydrogen evolution was significantly accelerated by the suppression of Zn deposition. Addition of stearyle benzyl ammonium chloride (C-18 benzyl) to the baths was effective for an increase in Al content in the deposit and Al was codeposited in trivalent state in the deposits; (2) The partial polarization curves of Zn were shifted to the less positive direction due to the suppressed rate of Zn deposition by additive C-18 benzyl (3) X-ray diffraction patterns of the deposited composites showed that the Al3+-compound that existed in the deposits was θ-Al2O3 (4) TEM observation revealed that the codeposited Al2O3 with a small size of 10 to 100nm was homogeneously dispersed in the deposits.
In mixed solutions of ethylene glycol and water, Al-Nd alloy films were anodized at 1mA cm-2 up to 100V. Al-10wt.% Nd and Al-3wt.% Nd sputtered films were used as substrates, and electrolytes containing various kinds of solute were used. After annealing at 300°C, FT-IR spectrum and dielectric strength were measured for each sample. By anodizing in the electrolytes, the species originating from the ethylene glycol are incorporated into the oxide films, as well as the anions of the solute. As a consequence of the incorporation, the electrical properties of the anodic films are varied. Whereas various kinds of electrolyte were used for two kinds of Al-Nd substrates, FTIR peak position associated with Al-O stretching vibration and the dielectric strength had a certain relationship. Therefore, it is considered that the insulating property mainly depends on the microstructure of the oxide films, and that the influence of a change in the oxide film composition is very small.
Diamond like carbon (DLC) and silicon containing DLC (Si-DLC) films were deposited by EBEP (electron beam excited plasma)-CVD. The effects of CF4 plasma treatment and Si-inclusion on DLC film on surface energy, nanoindentation hardness and nanoscratching properties were investigated. DLC and Si-DLC films were surface modified by CF4 plasma treatment. CF4 plasma treatment decreases surface energy evaluated by the liquid drop method. Si-inclusion decreases the nanoindentation hardness. CF4 plasma treatment decreases nanoindentaion hardness of DLC film, however increases the hardness of 20% Si containing DLC film. Micro wear depth increases by Si-inclusion evaluated by nanoscratch test. CF4 plasma treatment increases the micro wear of DLC film, however decreases the micro wear of 20% silicon containing DLC film. Friction coefficients of both DLC and Si-DLC films were decreased by CF4 plasma treatment.
To improve the reliability of high-density magnetic systems, a new thin protective layer against wear and corrosion must be applied on magnetic disk media. Various low-energy beams produced from N2, O2, CF4 and CH4 plasma were irradiated onto Co-Cr-Ta magnetic media, and then the effects on hardness, corrosion resistance and magnetic coercive force were studied, and the following results were obtained. (1) To clarify the relationship between hardness and plasma state, plasma spectroscopy analysis was performed. The hardness was affected by ion and radical quantities in the plasma. (2) Various low energy beam irradiations increase the surface Vickers and nanoindentaion hardness. Especially, nitrogen and CF4 beam irradiations increase the hardness. The modulus of dissipation in deformation energy decreases with hardness increase. (3) Various low energy beam irradiations remarkably improve corrosion resistance evaluated from natural corrosion voltage in distilled water and physiological salt water solution. (4) Proper energy beam irradiation slightly degrades the magnetic coercive force of a magnetic disk.
We have analyzed the interfaces in Auger depth profiles, for the Ni/Cr multilayer specimen, the GaAs/AlAs superlattice specimen and the InP/GaInAsP multilayer specimen, using curve fitting process by the logistic function. In consequence, the calculated fitted profile curves are in very good agreement with the measured points. Moreover, it has been found that the depth resolution function is expressed by two parameters of the interface-width and the asymmetry. In this report, we recommend that the surface roughening effect and atomic mixing effect are clearly shown using these two parameters.
Miniaturizing an electron device, characterization of ultra shallow region and ultra thin film is becoming important, and then high depth resolution has been required of the secondary ion mass spectrometry (SIMS). A measured depth profile is generally spread rather than the actual distribution because of atomic mixing and roughness caused by ion irradiation. We need a development not only in SIMS measurement procedure but also in analysis technique to presume a true depth distribution from a measured depth profile. In this paper, we report the evaluation of the depth resolution in SIMS data for boron nitride multi-delta-doped silicon and for isotope separated silicon dioxide on natural abundance silicon dioxide using physical model and we will demonstrate to presume a true depth distribution.