The present investigation is the first comprehensive comparative study of x-ray diffraction (XRD) and transmission electron microscopy (TEM) results to address the important issue of fcc Ti formation in nanoscale multilayers. Ti/Al multilayers with 7.2 and 5.2 nm composition modulation wavelengths were studied by reflection and transmission XRD as well as transmission electron diffraction (ED), high-resolution TEM, and energy-filtered TEM. Previous reports have claimed deposition of fcc Ti in multilayer systems. Our results demonstrate that the Ti in Ti/Al multilayers deposits in the hcp form and that fcc Ti is merely an artifact of producing specimens for cross-sectional TEM.

We discuss substrate temperature ramping effects during chemical vapor deposition of aluminum on nucleation density, texture, surface roughness, and resistivity of the resulting films. Results from three different process protocols are presented. Ramping the temperature down during the deposition from 673 K resulted in a larger fraction of small nuclei compared to deposition at a constant temperature of 573 K. From among the protocols studied, the lowest surface roughness was obtained by initially depositing for a short time while ramping the temperature down from 673 K, followed by deposition at 573 K, compared to all the other films. The same process protocol resulted in the highest Al(111) texturing, highest reflectivity, and lowest resistivity.

A lithium reduction technique to condition spent fuel for disposal has been developed at the Argonne National Laboratory. There is a need to ensure adequate vessel longevity through corrosion testing and, if necessary, materials development. Several ferrous alloys and tantalum specimens were submitted to a corrosion test at 725 °C for thirty days in an argon atmosphere, using a lithium-chloride salt saturated with lithium metal and containing small amounts of lithium oxide and lithium nitride. The samples did not show dimensional or weight change, nor could corrosion attack be detected metallographically. The lithium-saturated salt system did not show any behavior similar to that of liquid lithium corrosion. From testing in other gas compositions, it appears that the presence of oxygen in the system is necessary to produce severe corrosion.

Two- and three-layer composite models were developed using a beam vibration theory, and the models were applied for measuring Young's moduli of thin metallic films. The Cr, Ni, and Co-coated Si wafer composites (two-layer composite) and (Cr/Ti/Si) composites (three-layer composite) were produced by radio-frequency (rf) magnetron sputtering and used to test the developed models. Young's moduli of (Cr) films obtained by the three-layer composite model agree well with those of (Cr) films obtained by the two-layer composite model, considering (Ti/Si) as the one layer and (Cr) as the other layer. This suggests that moduli of multilayer films may be obtained by using a two-layer composite model repeatedly.

Iron oxide films were prepared by the polymer precursor method with alkaline metal (Li, Na, and K) ion doping. Alkaline metal ions were used to regulate the thermal decomposition process of the cation-citrate complex, that is, the precursor of the film. The spinel iron oxide films were obtained by firing the precursor with the alkaline ion doping [Na/Fe (atomic ratio) ≧ 0.2 and K/Fe (atomic ratio) ≧ 0.2] at 773 K for 5 min in air. The formation mechanism of the spinel iron oxide films was investigated by differential thermal analysis (DTA) and x-ray photoelectron spectroscopy (XPS) measurements. Formation of the carbon-iron oxide complex was observed, and this reduction atmosphere induced the formation of the spinel iron oxide films. This method gave the spinel iron oxide films of which nanostructures are controlled.

Thin films of La0.6Ca0.4MnO3 (LCMO) have been produced on (001) oriented LaAlO3 (LAO) and yttrium-stabilized zirconia (YSZ) substrates by liquid-delivery metalorganic chemical vapor deposition (LD-MOCVD). X-ray diffraction (XRD) analyses showed that the films were epitaxially grown on LAO substrates and were monocrystalline at a thickness of less than 500 Å. At a thickness of greater than 500 Å, the films became polycrystalline but maintained their high texture (preferred crystalline orientation). Films grown on YSZ were always polycrystalline but were also highly oriented. Regardless of the substrate, the 1500 Å thick polycrystalline films exhibited substantially significant magnetoresistance ratios even above room temperature.

Pb1−xCaxTiO3 thin films with x = 0−0.3 for pyroelectric applications were deposited on platinized silicon wafers by chemical solution processing. Ca-substitution for Pb in PbTiO3 results in a reduced c/a ratio of the unit cell, which, in turn, leads to better pyroelectric properties. Control of nucleation and growth during rapid thermal annealing to 650 °C allowed the formation of either highly porous or dense (111) oriented films. The inclusion of pores creates a matrix-void composite with the low permittivity desired for pyroelectric applications, resulting in a high figure of merit. The growth mechanisms for the microstructural evolution of both dense and porous films were analyzed by x-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Rutherford backscattering spectrometry and allowed establishment of microstructure/property relationships.

An aluminothermic reaction starting with inexpensive MoO3, SiO2, and Al powders was utilized to prepare molybdenum disilicide (MoSi2) powders by the micropyretic/combustion synthesis process and leaching. The combustion-synthesized product was porous and could readily be crushed into powders. X-ray diffraction (XRD) analysis revealed that the product of such a reaction consisted of α–Al2O3, MoSi2, and a small amount of Mo(Si,Al)2 and Mo5Si3. The reason for the formation of Mo(Si, Al)2 phase is discussed. MoSi2 powders were obtained by leaching out the Al2O3 from the synthesized powder mixtures in boiling phosphoric acid solution. The synthesized MoSi2 powders, including a small amount of Mo(Si, Al)2 and Mo5Si3, were very fine with an average particle size of about 1 μm.

The bombarding energy dependence of bonding structure in amorphous carbon interlayer and its effect on diamond nucleation density (Nd) were studied. Amorphous carbon (a-C) interlayer was deposited by magnetron sputtering. Interestingly, the intensity ratio (ID/IG) of the D band (∼1400 cm−1) to the G band (∼1570 cm−1) in the Raman spectra and the optical band gap of the a-C film were found to be inversely proportional to the sputtering power, that is, to bombarding energy. When diamond was subsequently deposited at 800 °C by microwave plasma chemical vapor deposition (CVD), diamond could be grown only on the interlayers with higher ID/IG (≥2.20), and Nd was increased up to 2 × 106/cm2 with the increase of ID/IG ratio, that is, with the decrease of the bombarding energy. We experimentally confirmed that the amount of the sp3 bonded carbon clusters within the interlayer was dependent on the bombarding energy of the particles, determining the diamond nucleation density. We suggest that the transformation of the amorphous carbon into graphitic carbon should be effectively prevented for the diamond nucleation on the a-C interlayer.

The effects of substrate cleaning, nitridation time, and substrate temperature in the range 800–1000 °C on the microstructure of AlN/Si(111) films grown by simultaneous plasma-assisted molecular beam epitaxy have been investigated. It has been demonstrated, using a combination of conventional and high-resolution transmission electron microscopy, that the interface structure, the film defect structure, and the film surface roughness are strongly related. The formation of single crystal 2H–AlN films with atomically flat surfaces occurs at 800 °C for conditions of 2.5 nm/min growth rate on very pure, atomically flat Si substrates.

A low-temperature (>450 °C) thermal chemical vapor deposition (CVD) process was developed for the growth of TaNx from the reaction of tantalum pentabromide, ammonia, and hydrogen. Studies of process reaction kinetics yielded two sequential rate-controlling steps, with an activation energy of 0.45 eV for the kinetically limited reaction regime. Additionally, a systematic design of experiments approach examined the effects of key process parameters, namely, substrate temperature, source temperature, and hydrogen and ammonia flows, on film properties. A wide CVD process window was established for nitrogen-rich amorphous TaNx with contamination below 1 at.%. Film conformality was higher than 95% in nominally 0.30 μm, 4.5: 1 aspect ratio, trench structures.

Structure and composition of the ferroelectric Pb(Zr, Ti)O3 layers in a capacitor of the ferroelectric random-access memory (FeRAM) device having a density of 64 k were investigated by transmission electron microscopy (TEM) together with the energy-dispersive spectroscopy (EDS) technique. The 250 nm thick PZT layer derived by the sol-gel route showed a 2–3% Pb-deficient, 3–4% Ti-deficient, and 5–7% Zr-excess composition at the top electrode interface compared to the bulk composition when they were as-fabricated. The local compositional nonuniformity became more critical as the integration process proceeded, which seriously degraded the ferroelectric hysteresis and the device yield. The major cause of the compositional variation was the outward diffusion of Pb through the capping barrier TiO2 layer during annealing at 650 °C. The AlN capping barrier layer was also not effective in suppressing the diffusion of Pb. However, the Al2O3/TiO2 double capping layer was very effective in suppressing the outward diffusion of Pb, and excellent ferroelectric characteristic was expected.

Formation of TiSi2 in titanium on nitrogen-implanted (001)Si with a thin interposing Mo layer has been investigated. The presence of a Mo thin interposing layer was found to decrease the formation temperature of C54–TiSi2 by about 100 °C. A ternary (Ti, Mo)Si2 phase was found to distribute in the silicide layer. The ternary compound is conjectured to provide more heterogeneous nucleation sites to enhance the formation of C54–TiSi2. On the other hand, the effect of grain boundary for decreasing transformation temperature was found to be less crucial. For Ti/Mo bilayer on 30 keV BF2+ or As+ + 20 keV, 1 × 1015/cm2 N2+ implanted samples, a continuous C54–TiSi2 layer was found to form in all samples annealed at 650–950 °C. The presence of nitrogen atoms in TiSi2 is thought to lower the silicide/silicon interface energy and/or the silicide surface energy to maintain the integrity of the C54–TiSi2 layer at high temperatures.

A versatile procedure of sputter deposition, well-adapted for getting a large range of Te/M ratios (with M = Zr or Nb), has led to the synthesis of several highly anisotropic zirconium and niobium polytellurides in thin film form. Upon tuning the two key parameters of the process, i.e., the Te percentage in the target and the substrate temperature during the deposition, preparation of systems ranging from ZrTe0.72 to ZrTe6.7, on the one hand, and from NbTe1.28 to NbTe7.84, on the other, has been achieved. Besides their amorphous or crystalline (with or without preferential orientations) behavior and their relationship to known structural types, the most striking feature of these films is their large departure from the stoichiometry of the bulk MTex reference compounds. This peculiarity, together with the possible changes of composition under annealing, are described and interpreted in terms of variable amounts of Te and M atoms trapped or intercalated within the parent structures.

Hard and transparent diamondlike carbon (DLC) films have been prepared on room-temperature substrates by using a C2H2–Ar plasma immersion ion processing (PIIP) method. The optical properties of the DLC films with different thicknesses deposited on PMMA (polymethyl methacrylate), silicon wafers, and glass plates were systematically examined. It was found that careful control of substrate bias voltage was needed for favorable growth of DLC films with low atomic hydrogen content, high hardness and wear resistance, and excellent optical properties. The resultant DLC films exhibited a low friction coefficient, high optical gap energy, and very high optical transmittance both in infrared and visible light ranges. The study confirmed that C2H2–Ar PIIP with low negative bias voltages and suitable C2H2/Ar gas ratios can produce optically transparent and hard DLC films on optical materials.

2-[3-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidine)-1-propenyl]-1,3,3-trimethyl-3H-indolium idoide (HICI) dye-doped SiO2 particles were synthesized by sol-gel method. Dimension, diameter, distribution, and homogeneity of the particles are closely related to the positively charged dye concentration, corresponding to the zeta potential of the particles. When the dye concentration reaches about 7.8 × 10−4 mol/mol SiO2, corresponding to the isoelectric point of the particles, the maximum particle size and the most homogeneity can be reached.

Highly photostable CdS nanoparticles modified with an alkyl group were prepared by an improved microemulsion technique using hexanethiol as cosurfactant. The surface-modified CdS nanoparticles catalyzed the photo-oxidation of 4-chlorophenol via continuously bubbling oxygen under uv light. The photocatalytic oxidation activity of the CdS nanoparticles was enhanced due to the formation of their compact CdS cores with strong chemical surface modification by heat treatment.

The effects of an electric field on phase separation in CBP (CaOB2O3P2O5) have been studied. It was discovered that an electric field can inhibit the process of phase separation in CBP glasses. If the electric field strength is increased, the inhibiting effect will increase, too. The mechanism of phase separation in an electric field has been discussed in light of the ir spectrum of CBP glasses.

Unsupported films and thin rods were prepared by the sol-gel method from solutions of triethoxysilane and methyldiethoxysilane. Measurements of elastic modulus, density, glass transition temperature, and refractive index were performed at different aging times. Results showed a large increase of the elastic modulus with aging time, which was related to the progressive condensation taking place in the xerogel network, as shown by solid-state nuclear magnetic resonance (NMR). The stiffness increase was shown to correspond to higher glass transition temperature and larger density and refractive index. Different increasing rates of the physical and mechanical characteristics were observed for films and rods during aging. This behavior was related to the different loss rate of the pore liquid, which affects the network evolution in the wet gel.

Bulk amorphous alloys of PdxNiyFe80−x−yP20 (25 ≤ x ≤ 60, 20 ≤ y ≤ 55, x + y ≥ 60) were prepared by a flux-melting and water-quenching method. Seven-mm diameter glassy rods of Pd40Ni40−xFexP20 (0 ≤ x ≤ 20) were studied in greater detail. For these alloys, the difference between the crystallization and glass transition temperatures ranges from 102 K for x = 0 to 53 K for x = 20. In this composition range, the reduced glass transition temperature, Trg, ranges from 0.66 to 0.57. The change in density upon crystallization ranges from 0.24 ± 0.04% for x = 0 to 1.33 ± 0.24% for x = 10. The partial molar volume of Fe in amorphous Pd40Ni40−xFexP20 alloys is significantly larger than the molar volume of (metastable) fcc Fe. This, as well as a comparison with the molar volumes of crystalline compounds, suggests chemically selective Fe–Pd bonding in these glasses.