Compliance with the increasingly stringent environmental laws will force the phasing out of conventional methods for the manufacture of all semiconductor devices. Development of processes with the highest possible material and energy efficiencies is the heart of the present ecological preservation efforts. Besides other benefits, rapid isothermal processing (RIP) also uses less energy than furnace processing. Further increase of material and energy efficiencies is possible by using rapid photothermal processing. Central to this method is the use of quantum photoeffects in conventional RIP systems. This approach can be consolidated with advanced chemical vapor deposition methods that further lower the wastages leading to systems that can give significant improvements over those presently used. Key experimental results and possible future directions are presented.

Micro-Raman spectroscopy is used to monitor the cooling-induced compressive deformation of carbon nanotubes embedded in an epoxy matrix. Young's modulus of single- and multiwall nanotubes may then be derived from a concentric cylinder model for thermal stresses, using the D*-band shift for each tube type. The resulting values of the elastic moduli are in very good agreement with predicted theoretical values, and with the published experimental data set of Treacy et al., Nature (London) 381, 678 (1996).

Electromechanical testing involving simultaneous electrical and mechanical measurements under load was used to study the fiber-matrix interface, the fiber residual compressive stress, and the degree of marcelling (fiber waviness) in carbon fiber composites. The interface study involved single fiber pull-out testing while the fiber-matrix contact electrical resistivity was measured. The residual stress study involved measuring the electrical resistance of a single fiber embedded in the matrix while the fiber was subjected to tension through its exposed ends. The marcelling study involved measuring the electrical resistance of a composite in the through-thickness direction while tension within the elastic regime was applied in the fiber direction.

Amorphous Ni50Pd40Si10 alloy powder was prepared by mechanical alloying. The surface states and catalytic activities of amorphous and crystalline Ni50Pd40Si10 alloy powder pretreated with hydrofluoric acid (HF) solution were studied. The results show that amorphous Ni-Pd-Si alloy powder was easily prepared by mechanical alloying. After treating with HF solution, the number of Pd atoms on the surface of amorphous Ni–Pd–Si powder was obviously higher than that of the crystalline alloy and catalytic activity of amorphous Ni–Pd–Si powder was higher than that of the crystalline one by three times.

A self-assembly technique was used for fabrication of a Si/metal interface in nanometer scale. Fine particles of gold of nanometer-order diameter were generated by a gas-phase condensation method and deposited on a Si substrate. Through a heat treatment and a cooling process, a nanoscopic Si–Au composite structure was formed on the surface of the Si substrate. Then, surface diffusing Si atoms played an important role for fabrication of the Si–Au structure which were epitaxially grown projecting onto the substrate. Furthermore, the Si/Au interface was atomically flat with no mixed-layer formation, and the Au nanoparticles also had the same crystal orientation as that of the Si dots in spite of a large lattice constant mismatch between them. This structure was considered to be fabricated as a result of minimization of the total surface and interface energy of the Si/Au system.

Silicon was pulse biased to −45 kV in a methane plasma generated by microwave excitation in the electron cyclotron resonance (ECR) mode. Hydrocarbon ions were accelerated in the electrical field and implanted into the silicon. Rutherford backscattering (RBS) measurements showed that it is possible to incorporate a concentration of up to 95 at.% C into the Si. Cross-section transmission microscopy (XTEM) showed that the resulting surface layer was amorphous. Annealing at 1250 °C resulted in the formation of 10 to 60 nm thick, crystalline SiC layers.

Structural and bonding characteristics of simplified (Pd, Te) precipitates have been determined in a simulated nuclear French glass using extended x-ray absorption fine structure (EXAFS) and x-ray diffraction. In this sample, these precipitates have a homogeneous composition, with about 10 wt.% Te. They retain a face-centered cubic structure as in pure Pd with a cell parameter which obeys Vegard's law. Pd K-edge EXAFS shows the presence of Te in the Pd coordination shell, with (Pd–Te) distances of 2.80 Å. These distances, higher by 0.05 Å than the (Pd–Pd) distances, may result in a lower packing efficiency of the CFC lattice. The comparison with the average distances derived from x-ray diffraction shows the nonmetallic character of the Pd–Te bond in these precipitates. These bonding modifications may cause the limited solubility of Te in metallic Pd.

The microstructures of PrBa2Cu3Oy during melt processing have been studied for samples quenched at different stages of the thermal cycle. The absence of the Pr2BaCuO5 phase in the Pr–Ba–Cu–O phase diagram, analogous to the Y2BaCuO5 (211) phase in the Y–Ba–Cu–O system, makes it interesting to study the microstructure of PrBa2Cu3Oy (Pr-123) during melt processing. The nature and morphology of the properitectic particles, the nucleation of Pr-123, and the microstructures resulting from melt processing are investigated and discussed as compared with those in YBa2Cu3Oy. At the properitectic stage the morphology of PrBaO3 (Pr-110) particles is angular. Pr-123 is found to nucleate on all Pr-110 particles with a needle-like morphology, whereas in other 123 systems no preferred morphology for the 123 during nucleation is observed. The melt textured microstructure of Pr-123 revealed similar features like domain formation with the trapped properitectic phase. The only difference is the absence of platelet gaps within domains as observed in other 123 systems. All these observations suggest that as compared to other 123 systems the microstructure of the Pr–Ba–Cu–O system behaves differently due to the absence of the analogous 211 phase.

Fine-grained monoclinic zirconia ceramic was made from well-dispersed zirconia sol prepared by the hydrolysis of zirconium chloride oxide octahydrate. Dechlorinated and concentrated zirconia sol was consolidated by pressure filtration. The relative green density of the compact was improved by the following cold isostatic pressing treatment at 400 MPa. The compact was densified by pressureless sintering to >98% of theoretical density in air at 1100 °C, which is lower than that of monoclinic to tetragonal transformation of pure zirconia. The average grain size of the sintered monoclinic zirconia ceramics was 92 nm.

The processes of rapid solidification from liquid to solid and heating from glass to crystalline for Ni3Al are simulated using molecular dynamics method. An amorphous state can be obtained by rapid solidification as long as the cooling rate is sufficiently large, which is very difficult to get in experiment. An fcc-type crystalline is obtained by heating the amorphous with a small heating rate. Based on the pair analysis technique, the microstructures of liquid, supercooled liquid, amorphous, and crystalline states of Ni3Al have been analyzed. Furthermore, the effects of cooling rate and heating rate on microstructures of Ni3Al during rapid solidification and heating processes have been discussed.

Optical transmittance of the nanocrystalline diamond films has been studied as a function of grain size of the diamond powder used for substrate pretreatment and the methane fraction in the source gas. It has been observed that for CH4 fractions below 13%, the films grown on substrates pretreated with finer diamond powder are more transparent, while this trend reverses for CH4 fractions above 13%. These variations in the transparency of the films correlate very well with their corresponding surface roughness. Nanocrystalline/amorphous diamond films with transmittance of greater than 80% beyond 700 nm and with average surface roughness as low as 61 Å have been obtained for CH4 fractions as high as 42% in the source gas. Interestingly, these films do not show an obvious presence of any graphitic carbon, and the structural ordering of the amorphous sp3-bonded phase also seems to be insensitive to the CH4 content of the source gas.

We report very large enhancement of static yield stress for electrorheological fluids by adding ferroelectric nanoparticles of lead zirconate titanate (PZT) or lead titanate (PbTiO3) to ER fluids consisting of 50 μm glass spheres. It is found that the enhancement peaks at certain nanoparticle/microparticle ratios for fixed solid/liquid volume fractions. The results are explained by calculations using an effective medium approach, based on the physical picture that the nanoparticles modify the properties of the liquid and solid components.

Matrix microstructure of a pitch-based carbon-carbon composite was controlled by an iodine treatment. Coal-tar pitch having the softening point of 101 °C was used as a matrix precursor. The iodine treatment was carried out on a pitch-impregnated specimen at 90 °C for 3–20 h. The specimen was carbonized at 800 °C and graphitized at 2000–3000 °C. The carbon yield increased from 73% to 93% by the iodine treatment. Microstructures of carbonized specimens changed from a flow type texture to a mosaic type one by the iodine treatment. The microstructural development to graphitic structure was suppressed by the iodine treatment.

Precipitates in GaN epilayers grown on sapphire substrates were investigated by atomic number contrast (ANC), wavelength-dispersive x-ray spectrometry (WDS), energy-dispersive spectrometry (EDS), and cathodoluminescence (CL) techniques. The results showed that the precipitates are mainly composed of gallium and oxygen elements and distribute more sparsely and inhomogeneously in directions in the sample grown on substrate nitridated for a longer period. Yellow luminescence intensity was imaged to be stronger in the precipitates. The results suggest that the precipitates are formed on dislocations and grain boundaries by substituting oxygen onto the nitrogen site, and result in the formations of deep levels nearby.

Crystalline CdSe particles were prepared by keeping the precursor solutions at temperatures above 60 °C. It was essential to use sodium sulfite as a stabilizing agent for selenium ions and sodium dicarboxylate as a complexing agent for cadmium in the precursor solution. The principal crystalline phase of the samples obtained at 60 °C was a cubic zincblende-type phase, but those prepared at 80 °C coexisted with a hexagonal wurtzite-type phase. The ratio of cadmium to selenium in the samples decreased with an increase of the concentration of selenourea in the precursor solutions, irrespective of the kind of complex agents and the keeping time of the precursor solutions. The band-gap energy of CdSe with an atomic ratio (Cd/Se) of 1 showed a value of 1.74 eV, but that with the ratio of 2.3 gave a slightly smaller value of 1.42 eV.

We have subjected single-walled carbon nanotube materials (SWNTM's) to a variety of organic functionalization reactions. These reactions include radioactive photolabeling studies using diradical and nitrene sources, and treatment with dichlorocarbene and Birch reduction conditions. All of the reactions provide evidence for chemical attachment to the SWNTM's, but because of the impure nature of the staring materials, we are unable to ascertain the site of reaction. In the case of dichlorocarbene we are able to show the presence of chlorine in the SWNT bundles, but as a result of the large amount of amorphous carbon that is attached to the tube walls, we cannot distinguish between attachment of dichlorocarbene to the walls of the SWNT's and reaction with the amorphous carbon.

Zircon-particle-dispersed Al−13.5Si−2.5Mg is a structural composite material being investigated for lightweight, tribological applications. The conventional, powder-processed material, in the temperature range of 22–100 °C, yielded a low coefficient of linear thermal expansion (CTE) of 7.8 × 10−6 °C at 0.15 volume fraction (Vf), a 64% reduction of that of the alloy. The dry sliding wear rate and the coefficient of friction measured by the pin-on-the-plate technique at 4 kg load decreased significantly by 99% and 35.5%, respectively. A significant reduction, by 29%, in wear rate of the alloy was observed to occur only when more than 0.03Vf zircon was dispersed. An x-ray study showed that the interface reaction products consist of compounds of Mg, Ce, Cu, and Nb. Tensile failure of the reaction-sintered parts revealed a ductile mode of fracture, with the path traversing both through voids and the bonded particles while interface failure was observed in parts without Mg. An analysis of both the tribological and tensile properties showed that an optimal performance of this alloy at 0.15Vf zircon is achieved when the Mg content is between 2.5 and 3.5 wt. %.

A substitute additive, HBF4, has been discovered that will replace Hg(NO3)2 catalyst for dissolving aluminum spent nuclear fuels in nitric acid for recovery of usable materials. The catalyst or substitute is necessary to penetrate a protective oxide film that continuously forms on the Al surface in the oxidizing acid. A penetration rate of alloy Al-6061 T6 of 40 mg/cm2-h can be achieved in a continuous dissolution process at 100 °C using a dissolvent of 0.15 M HBF4 in 7 M HNO3 that achieves a steady-state composition of 1.0 M Al3+ and 3.3 M HNO3, while maintaining a corrosion rate of a type 304L stainless steel dissolver vessel of 0.015 mm/mo. The penetration rate of aluminum is correlated with the equilibrium concentration of HF in the system. The postulated mechanism involves dissolution of the alumina film by approximately 0.006 M HF in equilibrium with the HBF4 and complexed aluminum fluoride species in nitric acid, which provide a large semi-buffered supply of HF. This allows the HNO3 to attack the aluminum metal. The small concentration of HF does not compete favorably with HNO3 for reaction with and consumption by Al.

Diamond was deposited at 850 °C by microwave plasma chemical vapor deposition (CVD) on the interlayers with various intensity ratios (ID/IG) of the D band (~1400 cm-1) to the G band (~1570 cm-1) in the Raman spectra. Diamond could be grown only on the interlayers with higher ID/IG (≤1.95), and Nd was slightly increased to 3 × 106/cm2with ID/IG. The predeposition at 350 °C, which decreased the full-width at half-maximum of the broad D band, further increased Nd to 5 × 107/cm2. With 300 ÅA Pt overlayer on the interlayer, Nd was much more enhanced to 8 × 107/cm2. We suggest the sp3 bonded carbon clusters within the interlayer contribute to diamond nucleation, but they should be survived against atomic hydrogen etching during diamond deposition by increasing the sp3/sp2 ratio, by increasing the degree in clustering, or by protecting them with overlayer.

Optical studies have been performed on amorphous films of the system Ge10Se90-xTex where (x = 20, 30, 40). The study revealed that as the Te content is increased, the optical band gap (Eg) was found to decrease. Photoinduced effects were studied on thin films samples irradiated with either white light or uv light. The shift in Eg due to photoirradiation disappears upon annealing the films at a temperature below the glass transition temperature. The effect of γ-radiation up to 8 kGy on the optical band gap was also investigated, and no detectable shift of the optical band gap was observed. The relationship between the optical band gap and both the average heat of atomization and the average coordination number of the compositions under investigation was studied.