A soft process for the intercalation of different ammonium cations into vanadium pentoxide was developed. By refluxing an aqueous solution containing ammonium , tetramethylammonium (CH3)4N+, and tetraethylammonium (C2H5)4N+ with V2O5 powders, intercalation compounds containing corresponding ammonium cations were obtained. The compound with aniline C6H5NH2 was also synthesized by the same process. The compounds with (CH3)4N+, (C2H5)4N+, and also C6H5NH2 had diffraction patterns consisting of very sharp 00l lines. The spacing for sandwiching the intercalates (the identity period), (CH3)4N+, (C2H5)4N+, and C6H5NH2, was 1.29, 1.31, and 1.39 nm, respectively.

A novel technique has been suggested for synthesis of highly dispersed oxide powders. The method is based on the treatment of aqueous solution of a multivalent metal nitrate (or chloride) by anion-exchange resin in the OH− form. The presented technique yields a stable colloid solution of the corresponding hydroxide with concentration up to 1 M. The subsequent freeze-drying and thermal dehydration results in very fine powder of metal oxide. The individual and multicomponent oxides obtained by the cryosol method were shown to possess unusual properties due to their high dispersity and chemical homogeneity.

Semiconductor-metal co-colloids of CdSey/Au have been prepared by various synthetic pathways. Their microstructure, including that of Au–CdSe(TOPO) co-colloid in a core-shell structure, has been examined by high resolution transmission electron microscopy (HRTEM) and found to be well defined within the 10 nm size range. The optical absorption spectra of the colloids and of various synthesis stages have been obtained.

Layered nanostructures of copper metal and cuprous oxide are electrodeposited from alkaline solutions of Cu(II) lactate at room temperature. No subsequent heat treatment is necessary to effect crystallization. The electrode potential spontaneously oscillates during constant-current deposition. At a fixed current density the oscillation period decreases as either the pH or temperature is increased. The oscillations are periodic in stirred solution, but show period doubling and evidence of quasi-periodic or chaotic behavior in unstirred solution. The phase composition and resistivity of the films can be controlled by varying the applied current density. The resistivity of the films can be varied over ten orders of magnitude. Scanning electron microscopy shows that the films are layered.

Electrochemical thin film deposition in aqueous mixtures containing Cd2+, Zn2+, and thioacetamide has been investigated. It has been found that the atom-by-atom growth of well-crystallized CdS thin film preferentially takes place at the early stage of the reaction, followed by the cluster-by-cluster growth of the poorly crystallized ZnS outer layer, thus resulting in the formation of CdS/ZnS bilayer by a one-step synthesis.

Calcium phosphate growth on cellulose fibers phosphorylated in 1.5 × SBF (simulated body fluid) solution at various temperatures from 36.5–60 °C was studied. Cellulose fibers phosphorylated by using urea and H3PO4 and then soaked in saturated Ca(OH)2 solution at ambient temperature were found to stimulate the growth of a calcium phosphate coating on their surfaces after soaking in 1.5 × SBF solution for as little as one day. Soaking in 1.5 × SBF solution at higher temperature produced a thicker layer of calcium phosphate on the fibers, which may be due to the decrease of solubility of calcium phosphate. The specific surface area of the coatings decreased with an increase of soaking temperature and soaking time in 1.5 × SBF solution.

KxGaxSn8−xO16 (x ≤ 2) powders with hollandite structure were prepared by the sol-gel method using metal alkoxides. Dried gels, when being annealed at 973 K, changed to well-crystallized hollandite powders with about 22 m2/g in BET value which consisted of needle-like crystallites 25 nm wide and 65 nm long in average. The specific surface area was nearly 100 times larger than that of the hollandite produced at 1648 K by the conventional method, and the preparation temperature was lowered by 500 to 700 K. The powders obtained at 973 K were characterized as an attractive porous material showing a pore size distribution profile sharply monodispersed at 10.7 nm in the mesopore range.

A kaolinite-organic intercalation compound containing methanol was proved to be a versatile host for further displacement reaction with alkylamines. Kaolinite-organic intercalation compounds with polar molecules, such as N-methylformamide (NMF) and formamide, were used as the starting materials. After stirring the kaolinite-NMF intercalation compound with methanol, the basal spacing increased to 1.11 nm. The 13C MAS NMR result of the product indicated that methanol was intercalated into kaolinite by partial displacement with NMF. By use of the methanol-treated kaolinite intercalation compound as the intermediate, alkylamines were intercalated into the interlayer space of kaolinite by displacing with methanol.

Epitaxially grown Fe3−xO4 films were prepared on MgO(001) substrates by dipping-pyrolysis process using CO–CO2 gas mixtures. The structure and in-plane alignment of these films were examined by x-ray diffraction θ-2θ scans, β scans (pole figures), and asymmetric ω-2θ scans (reciprocal-space maps). The films heattreated at 500 °C and higher in an atmosphere with pCO/pCO2 = 10−4 had a spinel-type structure and were in an epitaxial (cube on cube) relationship with the substrates.

A series of solid solutions (1 − x) ZrO2 · xY0.857 W0.143 O1.714 (1/7Y6WO12) of metastable cubic phase were synthesized at 800 °C through a polymerized complex method. Lattice parameter a0 of solid solutions varies linearly with Y0.857 W0.143 O1.714 content (x). Crystallization began to occur above 400 °C from amorphous precursor to yield at 800 °C fine powders of 6–10 nm and 19–40 m2/g for crystallite size and surface area, respectively.

The deposition area of diamond film is increased by applying a geometry of multiple cathodes and a single anode in direct current (dc) plasma assisted chemical vapor deposition (PACVD). Each cathode is made of Ta and connected independently to its own dc power supply. The operating pressure is 1.3 × 104 Pa (100 Torr), and methane-hydrogen mixed gas is used as reaction gas. The voltage and the current applied to each cathode are 650 V and 4 A, respectively. The transition from a diffuse glow to an arc is prevented by maintaining cathode temperatures above 2000 °C, which inhibits carbon deposition on the cathodes. Translucent diamond film of 3 in. diameter, thicker than 200 μm, is grown using seven cathodes with 3% CH4–H2 mixed gas for 110 h. The deposition area can be increased further by increasing the number of cathodes.

Oxygen-deficient, tetragonal thin films of YBa2Cu3O6+x with x ≈ 0.25, quenched from the deposition temperature, change to the oxygenated, orthorhombic phase with x ≈ 1, between 200 °C and 400 °C in flowing oxygen. The transition is not reversible in flowing oxygen, and cannot be completely reversed by cooling in flowing argon. We do not observe a transition of the orthorhombic films to the tetragonal phase up to 800 °C in flowing oxygen. We observe that the major impurity phases to appear under nonoptimal annealing conditions are oriented phases of YcuO2 and BaCu2O2, with Y2BaCu2O5 and Y2Cu2O5 conspicuously absent. These conclusions have been drawn from a study that uses perturbed angular correlation spectroscopy to probe the local microstructure of the films.

Using 4-circle x-ray diffraction and transmission electron microscopy, we have studied the microstructure and in-plane orientation of the phases present in thin film composite mixtures of Yba2Cu3O7–δ and Y2O3. We see a high degree of in-plane orientation and have verified a previous prediction for the in-plane order of Y2BaCuO5 on (110) MgO. Transmission electron microscopy shows the composite films to be a mixture of two phases, with YBCO grain sizes of ≈1 μm. We have also compared our observations of the in-plane order to the predictions of a modified near coincidence site lattice model.

Based on a thermodynamic assessment of the W–In–Ga–As quaternary system, the metal W was selected as a thermodynamically stable ohmic contact material to n-In0.53Ga0.47As. As-deposited contacts (on n ∼ 1.4 × 1018 cm−3 In0.53Ga0.47As) had average specific contact resistances of 7 × 10−7 Ω ·cm2 as measured using the transmission line model. The contact resistances remained unchanged after rapid thermal annealing at 400 °C for 1 min or at 600 °C for 1 min, and exhibited no degradation in electrical properties even after long-term annealing at 500 °C for 100 h. Transmission electron microscopic examination of the contacts showed no interfacial reaction. The present investigation demonstrates the power of thermodynamics in identifying stable ohmic contacts to multicomponent semiconductors.

The oxidation behavior of a nanolayered MoSi2/SiC composite material was determined at the temperature range of 400–900 °C in wet oxidation conditions. The samples were produced in the form of thin films using a sputtering technique from two different sources, and a rotating substrate holder, onto silicon single crystals and low carbon steel. For comparison, the oxidations of both constituents, MoSi2 and SiC, produced with the same sputtering technique, were measured separately. The microstructure of the MoSi2/SiC samples was determined with high resolution transmission electron microscopy (HRTEM), and the composition of the sputtered samples was measured using backscattering (BS) of protons. For quantitative determination of oxidation, the nuclear reaction 16O(d, p)17O was utilized. Oxide layers were also analyzed using a secondary ion mass spectrometry (SIMS) and the appearance of the oxidized surface with a scanning electron microscopy (SEM). As expected, the SiC films had both the lowest initial oxidation and steady state oxidation rate. The results show that the oxidation behavior of the MoSi2/SiC nanolayered composite material differs from that of both its constituents and involves a degradation mechanism of its own, resulting in the highest oxidation during the initial phase of the oxidation. A steady-state oxidation rate was observed after the initial transient phase to be the highest for the metastable C40 structure of the single MoSi2 layer. The oxidation rate of the nanolayered structure was retarded by the SiC layers. No signs of pest disintegration were observed on either of the MoSi2 containing coatings during the steady-state phase of the oxidation at 500 °C up to 40 h. Our results show that the oxidation of nanolayered structures can be only in part explained by the oxidation behavior of the constituents and that during the steady-state oxidation of the nanolayered structure the oxidation rate is largely determined by the constituent with the lowest oxidation rate and by the layered structure.

Interfacial precipitation in sol-gel derived, titania-doped diphasic mullite gels was investigated using conventional and high resolution transmission electron microscopy. Rutile, anatase, and brookite precipitated on the interface between {110} planes of mullite and glass pockets in the sintered body. The formation of brookite may be attributable to the Si- and Al-rich environment during precipitation. Each polymorph of titania has a unique morphology and orientation relationship with mullite. Brookite exhibits a truncated pill box shape, and anatase displays a vermicular morphology. Quenching experiments suggest that the precipitates grow and undergo phase transformations during cooling.

(Pb1−xBax) (Zr0.75Ti0.25)O3 ceramics were modified with Y3+ and Nb5+, and their dielectric and electrostrictive properties were investigated as a function of x (0.23 ≤x ≤ 0.33). With increasing Ba2+ content, the axial length (a) was increased and distortion of rhombohedral angle (90°-α) approached to zero, resulting in the increased symmetry of the (Pb1−xBax)0.96Y0.02(Zr0.75Ti0.25)0.98Nb0.02O3 structure. As the Ba2+ content increased, the maximum dielectric constant decreased and the curve of field-induced strain became a parabolic one with lower hysteresis of strain. When 25−27 mol% of Ba2+ was substituted on the Pb2+ sites, the specimens showed excellent electrostrictive properties which were 1.04−1.17 × 10−3 of longitudinal strain and 12–18% of hysteresis of strain at 10 kV/cm.

A system of (1 − x)Pb(Yb1/2Nb1/2)O3 (PYN)–xPb(Mg1/3Nb2/3)O3 (PMN) (0 ≤ x ≤ 1) has been investigated with regard to its phase transition, densification, and dielectric and electrostrictive properties. According to the XRD study, a crystal structure transformed from orthorhombic to pseudocubic at approximately x = 0.22. The superlattice peaks were gradually weakened with increasing x, and disappeared above x = 0.22. Increasing x led to an increase in the maximum dielectric constant and a decrease in transition temperature over the entire composition range. As a result of P-E hysteresis loops, successive phase transitions of ferroelectric-antiferroelectric-paraelectric were observed to occur in the range of 0.18 ≤ x ≤ 0.25 with increasing temperature, while the direct transition into the paraelectric region was found to take place for x ≥ 0.3. From the field-induced strain measurement, high electrostrictive coefficients, 7.3–8.2 × 10−2 (m4/C2), were determined in the PYN-rich range (x ≤ 0.1). Based on the results, a phase diagram of the system was constructed with variations in x and temperature.

The effects of Al and Nb doping on the leakage current behaviors were studied for the Ba0.5Sr0.5TiO3 (BST) thin films deposited on Pt/Ti/SiO2/Si(100) substrate by rf magnetron sputtering. Al and Nb were selected as acceptor and donor dopants, respectively, because they have been known to replace Ti-sites of the BST perovskite. The BST thin films prepared in situ at elevated temperatures showed relatively high leakage current density and low breakdown voltage. However, the BST thin films deposited at room temperature and annealed subsequently in air showed improved electrical properties. In particular, the leakage current density of the Al-doped BST thin film was measured to be around 10−8 A/cm2 at 125 kV/cm, which is much lower than those of the undoped or Nb-doped thin films. The results suggest that the Schottky barriers at grain boundaries in the film interior could determine the leakage behavior in the BST thin films.

Surface morphologies and microstructures of epitaxial (Pb1−xLax)TiO3 (PLT, x = 0.00, 0.08, 0.16, and 0.24) thin films grown on (001) MgO have been investigated using SEM, AFM, and TEM. Surface roughness of PLT films varies severely with La concentration. For 0.08La-PLT film, very smooth surface has been achieved with 9.3 Å of RMS roughness. 0.00La- and 0.08La-PLT films show 90° domain structure, and periodic dimension of the domain is reduced by La substitution. 0.16La- and 0.24La-PLT films show the presence of triangular grains, causing rough surface and poor crystal quality. However, they are distributed uniformly in 0.16La-PLT film while agglomerated in 0.24La-PLT film. Optical propagation losses of PLT films measured by prism coupling technique were 22.3, 6.0, 11.4, and 20.7 dB/cm for x = 0.00, 0.08, 0.16, and 0.24, respectively. Such a variation in optical losses seemed to be due to the surface morphology and abundance of domain boundaries that change continuously as a function of La concentration in epitaxial PLT thin films.