Shadowing growth by glancing angle deposition (GLAD) has been providing self-assembled nanostructures over much larger area for much lower costs since much earlier than the recent advanced top down processes do. In these two decades, significant progress has been made in the development of the well-controlled 3D nanomorphologies such as zigzag and helix. Much effort for theoretical and numerical understanding of the growth mechanism has been also paid in order to improve the morphology. Many researches in academia have been investigating useful properties of nanocolumnar thin films in their laboratory. On the other hand, most companies seem hesitate to introduce GLAD technique into the factory due to the prejudice that the obliquely deposited thin films are not durable and reproducible. In this article, we discuss the progress in glancing angle deposition technology for the practical applications.
A partial pressure gauge was developed with a quartz sensor to measure partial pressures of silane and hydrogen gases in gas mixtures, which are used as the sources of thin film silicon solar cells. The partial pressures were derived from the dependencies on viscosity and molecular weight of these mixtures, which can be measured using the quartz sensor. The partial pressure gauge developed based on this principle measured partial pressures of silane and hydrogen in gas mixtures for 133-1,333 Pa and 0, 20, 40, 60, 80, and 100vol.% silane with resolution of 0.01vol.% for gas mixtures including over 20% silane partial pressures, which are typical preparation conditions for thin film silicon solar cell materials. This pressure gauge can be used in practical application to measure the partial pressures of silane and hydrogen in mixtures.
One of the reasons of a beam loss in a high power accelerator is leakage magnetic field from a magnet at a close beam line, which distorts the beam orbit and makes the beam hit the wall of the beam pipe. The most effective way to shield such leakage field is to cover the beam by the magnetic materials at the nearest space. This means that beam pipes and bellows be made of the magnetic materials. We plan to apply this method to the vacuum chambers of the beam extraction section of the J-PARC 3 GeV synchrotron, where the effect of the leakage magnetic field to the beam orbit is evident. However, there is few proven evidence of the vacuum chambers made of magnetic materials. Therefore we clarify the problems in producing beam pipes and bellows, which satisfy the magnetic and vacuum performance. In this article, we deliver the over view of the magnetic shielding project and our approaches to the problems in producing the vacuum chambers of magnetic materials.
A method for the source apportionment of individual particles was developed by using high lateral resolution time-of-flight secondary ion mass spectrometry (TOF-SIMS). The procedure of this method was optimized through the analysis of some kind of pure metal particles. This method was applied to the aerosol particles collected for a week at Fukue-Island in Japan. As the results, the aerosol particles on characteristic days were classified into 10 clusters with different sources. The variation of pollution aerosols was consistent with that deduced by the bulk chemical analysis. We concluded that the developed method was effective to the source apportionment of suspended particulate matters.
Thiols and carboxylic acids are important molecules for the anchor of Self-Assemble Monolayer (SAM) on metal surface in organic devices. In order to consider whether carboxylate or thiolate adsorbs on various metals, adsorption energies of methanthiolate and acetate on various metals were thermodynamically calculated using basic quantities of formation enthalpies of metal oxides (Hf(MxOy)) and metal sulfide (Hf(MxSy)). The calculations were carried out for the adsorption on clean, O adsorbed, and OH adsorbed surface. The results suggested that methanethiolate adsorbs on all clean metals, and on O and OH adsorbed metals except Ti and Al (the high Hf(MxOy) metals). On the other hand, acetate adsorbed on all O and OH covered metals, and the clean metals except Au, Ag and Pt (the low Hf(MxOy) metals). As the modification of electrodes using SAM is carried out under atmospheric and liquid conditions, it is considered that thiols prefer the adsorption on the low Hf(MxOy) metals to the high Hf(MxOy) metals, on the contrary, carboxylic acids prefer the adsorption on the high Hf(MxOy) metals to the low Hf(MxOy) metals.
In this study, a remarkable feature of the method that fabricates Titanium-Doped Zinc Oxide (TZO) films is used to deposit films in a magnetic field caused by the rare earth magnet, NdFeB arranged between the target and substrate. The magnetic field is applied perpendicular to the plume. As a result, the resistivity of the films fabricated in the magnetic field decreased from 1.26×10−3 to 6.99×10−4 Ω•cm. Furthermore, the average transmittance in the visible wavelength region (400-700 nm) increased from 77.0% to 81.3%, and that in the wavelength region applicable to the tandem type solar cells (400-1500 nm) increased from 84.2% to 85.5% for the films fabricated in the magnetic field. Furthermore, an average transmittance in the wavelength region corresponding to the whole solar spectra (400-2500 nm) was 71.4%.
We have investigated the H2 molecular adsorption on the Ag(111) surfaces. To treat van der Waals (vdW) interaction accurately, we performed first principles calculation based on spin-polarized density functional theory (DFT) with the semiempirical correction term of vdW interaction. We got the value of 36.0 meV as the depth of potential energy with this method. We also found that in-plane diffusion barrier was less than 1.3 meV, and zero-point energy about perpendicular direction to the surfaces was 5.0 meV. Totally, the adsorption energy of H2/Ag(111) was 31.0 meV, which accordingly agreed with experimental value of 25.5 meV. We also calculated the ortho-para H2 conversion rate with the anisotropic potential energy. We found that this anisotropy induced the hindered rotational state, which imposed steric effects and accelerated ortho-para H2 conversion.
We have investigated the converging behavior of argon gas cluster ion beam passed through a glass capillary. The gas cluster ions are attractive as a projectile for SIMS from the view point of minimization of the damages. The cluster ion beam of 5 keV consisting of 500∼3000 argon atoms was injected in the capillary. The inner diameters of the capillary at the inlet and outlet were 0.8 mm and 9.6∼140 μm, respectively. Ion current from the outlet of the all the capillaries were detected. We obtained the converging factor of 2∼7, which depended on the incident ion current. The kinetic energy of the incident ions was found to be reduced by 20∼30% by passing through the capillary. Contrary, the velocity of the ions was not changed. These facts suggest that the cluster becomes 20∼30% smaller in mass by passing through the capillary. As far as we know, this is the first report on the study of the converging of cluster ions by using a glass capillary.
A pulsed corona μ plasma was used to modify the surfaces of microchannel walls of commercial cyclic olefin copolymer microfluidic chips. Pt wire electrodes were inserted into the reservoirs of a chip in order to develop surface discharge along the microchannel inner wall. He, Ar and room air μ plasmas were generated throughout a 60-mm-long microchannel at a crude vacuum of 0.8-30 kPa using a discharge pulse spacing of 5 ms, a pulse duration of 0.7 ms and Vpp of 8-9 kV. He and Ar atomic excitation temperatures estimated using Boltzmann plots were approximately 9,600 K and 23,700 K, respectively, whereas the gas remained at room temperature. The plasma-treated microchannels exhibited highly hydrophilic properties. X-ray photoelectron spectroscopy revealed that the oxygen-containing polar groups such as -C-O-, C=O and -COOH were introduced into the plasma-treated inner walls. Furthermore, microchannels treated by such energetic plasma showed no damage and had smooth surfaces.
We developed a new PDP manufacturing method in which protective layer deposition and sealing were performed continuously in high vacuum (pressure range 10−6 Pa), to keep the protective layer surface as clean as possible (“all-in-vacuum”). The “all-in-vacuum” panel shows high performance: 1) short aging time, 2) low firing voltage, and 3) short statistical time lag. Especially, the short statistical time lag is not obtained once the MgO layer is annealed in ambient air, even though the annealed MgO layer is activated in high vacuum.