Mixed-phase diamond/β–SiC composite films with compositional gradient were prepared by microwave plasma-assisted chemical vapor deposition using a gas mixture of hydrogen, methane and tetramethylsilane (TMS). Single-crystalline silicon wafers, pretreated with diamond nanoparticles before deposition, were used as substrates. The film characterization by scanning electron microscopy, electron probe microanalysis, and energy-dispersive x-ray analysis shows that the contents of diamond and silicon carbide in the films vary with TMS flow rate. Diamond/β–SiC composite films with compositional gradients are achievable by varying the TMS flow rate during the film growth process.

We examined the densification of 12CaO · 7Al2O3 (C12A7), which has a microporous lattice framework with a cavity of approximately 0.4 nm. Fully densified translucent ceramics are obtained when hydrated C12A7 powders prepared as precursors are sintered in a dry oxygen atmosphere at 1300 °C. The average transmittance between 400–800 nm for 1-mm-thick samples is improved up to approximately 70% with a 48-h increase in the sintering time. Dissociation of water molecules at the grain–pore interface into grains which entraps hydroxide ions in the crystallographic cage, and the release of the hydroxide ions into the atmosphere during the sintering procedure are considered to play crucial roles in the pore-annihilation processes.

Effects of an Al2O3 nanothin film between the emitting layer and the sputterdeposited cathode were studied for organic light-emitting diodes (OLEDs) with indium–tin–oxide, NN′-dephenyl-NN′-bis)(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine, tris(8-hydroxyquinoline)aluminum (Alq3), and aluminum (Al) as an anode, a hole transport layer, an emitting layer (EML), and a cathode, respectively. The performance of the OLEDs with sputter-deposited Al cathodes was inferior to that of the OLED with the evaporated Al cathode. However, the insertion of an Al2O3 nanothin film with a proper thickness between the EML and the sputter-deposited Al cathode was effective to alleviate performance degradation of the OLEDs with sputter-deposited Al cathodes in current flow and light emission. It is considered that both protection of EML by Al2O3 from the sputtering damage and higher luminance by the presence of a thin insulating layer between the EML and the cathode alleviated performance degradation of the OLED with an Al2O3 cathode buffer layer. The Al2O3 buffer layer could not alleviate quantum efficiency reduction caused by the sputtering damage.

Magnetic structure and domains of hydrothermal NiZn ferrites were studied through magnetic force microscopy by using different magnetically characterized tips. The magnetic patterns varied according to the tip employed and were correlated to the magnetic induced field generated by these different coated tips. Low-moment tips were found to be the most adequate to study magnetic domains in these hydrothermal ferrites.

The relaxation time scales in a commercial-grade Zr41.25Ti13.75Ni10Cu12.5Be22.5 (at.%) bulk metallic glass were examined using transient and dynamic mechanical experiments. The viscoelastic and sub-Tg relaxations were well described by the Kohlrausch–Williams–Watts relaxation function. A large activation energy (4.0 eV) and small nonexponentiality parameter (approximately 0.5) were observed for viscoelastic relaxation above Tg consistent with the cooperative nature of atomic movements leading ultimately to viscous flow. Conversely, a small activation energy (0.1 eV) and large nonexponentiality parameter (approximately 0.9) were observed for the sub-Tg relaxation suggesting localized atomic adjustments which may involve different structural units or mechanisms. The glass transition was manifested as a decoupling of the sub-Tg and viscoelastic relaxation. The resulting transition temperature determined at a selected time scale was in agreement with the value obtained from calorimetric studies.

Atomic force microscopy (AFM) nanoindentation experiments were performed on a Co(10.1) monocrystal. Using AFM line scans, we deduced the elastic recovery, which is an intrinsic parameter of the studied material. The comparison of these elastic recovery values with those calculated by standard nanoindentation shows a fair agreement for forces higher than 400 μN with an important discrepancy for lower forces. This difference is attributed to tip shape effects and to the AFM cantilever elastic deformation. Furthermore, the material hardness was measured from AFM images of the imprint by considering the lateral dimension L. In this case, the obtained values are practically independent from the applied load. Moreover, a simple model based on geometrical considerations is proposed to correct hardness values calculated from the residual depth.

YBa2Cu3O7−y(Y123) and Nd1+xBa2−xCu3O7−y (Nd123) films were deposited by the metalorganic deposition method, and the growth mechanism of these films was investigated by high-resolution transmission electron microscopy and energy dispersive x-ray spectroscopy. The Y123 and Nd123 films were prepared by spin-coating LaAlO3 (001) and SrTiO3 (STO) (001) substrates, respectively, with solutions including trifluoroacetates. Then, the samples were heat treated at 673 K in a humid O2 gas flow to form amorphous precursor films. Finally, the precursor films were heated at higher temperatures for 0–30 min in a humid Ar/O2 gas flow and cooled rapidly from those annealing temperatures. It was found that CuO crystals with a size of 10–20 nm are segregated in the Y123 and Nd123 amorphous precursor films. In the Y123 quenched film prepared by cooling the precursor film rapidly after the heat-treatment at 1048 K for 30 min, a polycrystalline film including Y2Cu2O5, BaF2, and CuO crystals was found to be generated on the c-axis-oriented Y123 film. In contrast, in the Nd123 quenched films, (NdBa)2CuO4(Nd201) phase was found to be formed first on the surface of the STO substrate. In conclusion, the c-axis-oriented Y123 film is formed by diffusion and reaction of Y2Cu2O5, BaF2, and CuO crystals, and the Nd201 phase reacts with BaF2 and CuO crystals in a humid atmosphere to form a c-axis-oriented Nd123 film.

The possible role of microstructural features in determining the self-affinity of the fracture surface of a cast aluminum alloy is explored in this work. Fracture surfaces generated both in tension and impact tests were topometrically analyzed by atomic force microscopy, scanning electron microscopy, and stylus profilometry. The roughness exponent exhibited the “universal” value ζ ≈ 0.78, and the correlation length ζ was of the order of the grain size. The brittle intermetallic compounds known to be important in crack initiation did not show any correlation with the self-affine parameters of the resulting fracture surfaces in this particular case.

Ordered PbSe crystalline nanowire arrays have been successfully fabricated in the nanochannels of porous anodic alumina membrane by direct current electrodeposition. X-ray diffraction and selected area electron diffraction investigations demonstrate that the PbSe nanowires have a uniform cubic structure. Electromicroscopy results show that the nanowires are quite ordered with diameters of about 50 nm and lengths up to 5 micrometers. X-ray energy dispersion analysis indicate that Pb:Se is very close to 1:1. The optical absorption spectrum of these PbSe nanowires show that there exist two peaks at 280 and 434 nm, respectively, attribute to excitonic absorption peaks.

Phase transformations in synthetic hexacelsian were investigated by hot-stage transmission electron microscopy. A second phase transformation from an orthorhombic to hexagonal structure was identified in the synthetic hexacelsian at approximately 700 °C. The hexacelsian was found to exhibit a sequence of phase transformations on heating of hexagonal (P63/mcm)–orthorhombic (Immm)–hexagonal (P6/mmm). Antiphase domain boundaries, which were observed in P63/mcm and Immm phases, were absent in the P6/mmm phase. Crystal symmetries of the three phases were determined by convergent beam electron diffraction, and space group symmetries were derived by comparison of experimental selected area electron diffraction patterns with computer-simulated patterns.

The present semiconductor cleaning technology is based upon RCA cleaning [W. Kern and D.A. Puotinen, Cleaning Solutions Based on Hydrogen Peroxide for use in Silicon Semiconductor Technology (RCA Rev., 1970) pp. 187–206], a high-temperature process that consumes vast amounts of chemicals and ultrapure water (UPW) [T. Futatsuki, T. Imaoka, Y. Yamashita, and K. Mitsumori, J. Electrochem. Soc., 142, 966 (1995)]. Therefore, this technology gives rise to many environmental issues, and some alternatives such as electrolyzed water (EW) are being studied. In this work, intentionally contaminated Si wafers were cleaned using electrolyzed water. The electrolyzed water was generated by an electrolysis system that consists of anode, cathode, and middle chambers. Oxidative water and reductive water were obtained in the anode and cathode chambers, respectively. When a NH4Cl electrolyte was supplied in the middle chamber, the oxidation–reduction potential and pH for anode water (AW) and cathode water (CW) were +1050 mV and 4.8, and −750 mV and 10.0, respectively. AW and CW deterioriated after electrolysis but maintained their characteristics for more than 40 min, which was sufficient for cleaning. Their deterioration was correlated with CO2 concentration changes dissolved from air. Contact angles of UPW, AW, and CW on DHF-treated Si wafer surfaces were 65.9°, 66.5°, and 56.8°, respectively, which characterizes clearly the electrolyzed water. To analyze the amount of metallic impurities on Si wafer surface, inductively coupled plasma, mass spectroscopy was introduced. AW was effective for Cu removal, while CW was more effective for Fe removal. To analyze the number of particles on Si wafer surfaces, we used the particle measurement Tencor 6220. The particle distributions after various particle removal processes maintained the same pattern. Overflow of EW during cleaning particles resulted in the same cleanness as that obtained with the RCA cleaning process. The roughness of patterned wafer surfaces after EW cleaning was similar to that of as-received wafers. Regardless of process sequence in this work, RCA consumed about 9 l of chemicals, while EW consumed only 400 ml HCl electrolyte or 600 ml NH4Cl electrolyte to clean 8-in. wafers. It was thus concluded that EW cleaning technology would be very effective for releasing environmental safety, and health issues in the next generation of semiconductor manufacturing.

Semiconductive nanocrystals of stannic oxide (SnO2) were precipitated in silica (SiO2) glasses synthesized via a sol-gel route. Kayanuma's equation, which describes the quantum confinement of an electron–hole pair in a semiconductive particle, well explained the absorption-edge shift due to the SnO2 nanocrystals in the optical absorption spectra. The adequate anneal of the SnO2–SiO2 glass ceramics in H2 gas led to the decomposition of the SnO2 nanocrystals and concurrently the production of twofold-coordinated tin atoms (Sn20 ) that provided a violet photoluminescence. The thermal behavior was studied with the x-ray diffraction measurement and photoluminescence and photoluminescence excitation spectroscopy.

A novel aerodynamic pressure-sensitive paint (PSP) was prepared by using the sol-gel process for measuring the pressure distribution variation on an aerodynamic surface with an oxygen-containing gas flow. In this PSP, RuII complexes as oxygen-sensitive probe molecules excited with visible light of 436 nm were dispersed into the organic modified silica matrix film prepared by the sol-gel method. A linear relationship between the emission intensity and the oxygen partial pressure was achieved in the airflow pressure range of 10.1–405 kPa, and the slope that represents the sensitivity of PSP for oxygen quenching reaches 0.75. A pressure distribution map was demonstrated showing a spatial resolution of 0.25 mm.

The adhesion of copper and various dielectric materials to tungsten carbide was studied using interfacial critical debond energies obtained by the four-point flexure method. Tungsten carbide (W2C), films 33.3 nm thick, were vapor deposited onto SiO2, spin-on carbon polymer resin (CPR), chemically vapor deposited organosilicate glass (OSG), and spin-on siloxane-organic polymer (SOP) surfaces using direct-current magnetron sputtering of a W metal target and a methane substrate plasma. Thick copper films (42.5 nm) were vapor deposited onto W2C. Some interfaces were modified by an Ar plasma, 1-nm W deposition, or O2 plasma treatment prior to Cu deposition. A W2C film deposited onto a CPR substrate was annealed for 2 h at 673 K in a 99% N2/1% H2gas mixture. For the untreated dielectric surfaces, the debond energy ranged from 39.9 to 3.95 J/m2. In order of descending adhesion energy, the substrates are ranked CPR, SiO2, SOP, and OSG. Ar plasma treatment of the SiO2 surface increased the debond energy from 20.3 to 41.3 J/m2. The Cu/W2C debond energy was 20.4 J/m2. Ar plasma or 1-nm W deposition treatment to the carbide surface moved the point of delamination from the Cu/W2C interface to the W2C/CPR interface for a Cu/W2C/CPR multilayer structure.

Nanocomposite materials consisting of ZrO2 and Pd phases were prepared by heating the amorphous Zr65Pd35 alloy for 24 h at 553 K in air. The maximum hydrogen absorption amount is about 2.4 mass% (H2/Pd) at 323 K and 2.2 mass% (H2/Pd) at 423 K at hydrogen pressure of 1 MPa. The absorption amount of Pd nanoparticles in the nanocomposite is a few times larger than those for the bulk and powder Pd metals. The remarkable increase in the hydrogen absorption/desorption amounts seems to result from the isolated dispersion state of Pd nanoparticles in the ZrO2 phase containing a tremendously large interface area in the nanocomposite.

A microscopic theory of thermally induced crack healing in poly(methyl methacrylate) is presented. Both laser-induced cylindrical cracks and knife-induced surface cracks were analyzed. For a given temperature, the crack closure rate was constant for both types of cracks. However, the crack closure rate was lower for samples with cylindrical cracks than for those with surface cracks. The former exhibited higher activation energy for crack closure than the latter, because the knife-induced cracks had sharper crack tips. Fracture stress was proportional to surface crack healing time to the one-fourth power for thermal healing at a given temperature. Based on the reptation model of polymer chains, the activation energy of chain diffusion was calculated. The healing process was monitored via fractography and crack closure was confirmed. The results were compared with solvent healing and thermal healing in the literature.

Optical studies of conformal GaAs layers grown on silicon substrates were carried out by cathodoluminescence, photoluminescence imaging, and micro-Raman spectroscopy. These techniques revealed, in the conformal GaAs layers, local variations of the luminescence intensity with the shape of stripes both parallel and perpendicular to the GaAs seed, associated with local variations of tensile stress. The cathodoluminescence and micro-Raman spectra suggest that this distribution of tensile stress plays an important role in the formation of mid-gap states responsible for the variations of the luminescence intensity. The high luminescence emission of the conformal GaAs layers compared to the emission of the GaAs seed grown directly on the Si substrate is consistent with the high quality of the conformal layers.

The LaNiO3 (LNO) thin films were deposited on Si substrate by rf magnetron sputtering. The interface and electrical properties of LNO/Si contacts were investigated. For the deposition at room temperature, an amorphous LNO film with a clean interface was formed on the Si. However, a thin silicon oxide layer of approximately 2.5 nm was formed at the interface between LNO and Si after rapid thermal annealing (RTA) at temperatures ≥450 °C. On the other hand, a highly (100)-textured LNO film along with an interfacial oxide layer of approximately 6.0 nm was obtained for the deposition at 400–450 °C. Nevertheless, if an ion beam etching was applied prior to the high temperature deposition at 400–450 °C, a clean interface at the interface could be obtained for the LNO/Si contacts. Moreover, crystallites with (111) planes grown epitaxially along the (111) planes of Si were found in the LNO films. All the contacts had shown good current–voltage characteristics of a Schottky diode with a barrier height of 0.69–0.78 eV for the LNO/n-Si contacts and 0.60–0.67 eV for the LNO/p-Si contacts, and the barrier height increased with the thickening of interfacial oxide layer. From the measurement of capacitance (C) under reverse bias (Vr) of the contacts made with LNO deposited on the ion-etched Si substrates, a linear relation was observed in the plot of C−2 against Vr except a deviation of linearity in the low-bias part of the curve. This deviation is most likely due to the segregation and inward diffusion of La and Ni near the interface of LNO/Si contacts. Nevertheless, the barrier heights evaluated from an extrapolation of linear part of the plots are reasonably consistent with those obtained from the I–V measurement.

Flame spray pyrolysis (FSP) has been used to synthesize high-surface-area ceria from cerium acetate in acetic acid solution. With the addition of an iso-octane/2-butanol mixture to that solution, homogeneous CeO2 nanoparticles were obtained. The specific surface area of the powders ranged from 240 to 101 m2/g by controlling the oxygen dispersion and liquid precursor flow rates through the flame. Furthermore, for production rates from 2 to 10 g/h a constant average primary particle size could be obtained at selected process parameters. The ceria showed high crystallinity and primary particles with a stepped surface. The powder exhibited good thermal stability and conserved up to 40% of its initial specific surface area when calcinated for 2 h at 900 °C. This shows the potential of FSP made ceria for high-temperature applications as in three-way catalysts or fuel cells.

The new generation of semiconductor metallization is based on Cu-film technology. In this paper we report on detrimental changes in surface morphology of self-passivated-Cu–1 at.% Al films which were magnetron-sputtered on Si substrates. Large voids appeared at grain boundaries after annealing, oxidation at temperatures at or above 500 °C, and cooling to room temperature under vacuum. Grain-orientation imaging with electron backscatter diffraction revealed that preferentially high-energy grain boundaries were voided. Contrary to reports in the literature, void growth was not prevented by the extremely clean ultrahigh-vacuum conditions during film fabrication nor by the strong and very sharp grain texture. Instead, it was clearly correlated with the stable surface oxide on the self-passivated films. Void growth was not found after annealing passivation-free films such as pure Cu or unoxidized Cu–1 at.% Al films.