An aqueous nitrate metalorganic deposition (MOD) process was used to form a 30-nm-thick c-axis-textured ceria (CeO2) layer on a yttria-stabilized zirconia (YSZ) single-crystal substrate. X-ray diffraction showed the CeO2 layer was an (001) oriented film with a ω-scan full width at half-maximum of 1.47°. The average roughness of the ceria films, measured by atomic force microscopy, was about 5 nm. Critical current densities of up to 3.6 × 106 A/cm2 were measured on a 0.35-μm Ba2YCu3O7−x (YBCO) layer deposited over this cap layer using a trifluoroacetate (TFA)-based MOD ex situ process. The physical vapor deposition-derived ceria cap layer used in the most common coated conductor buffer layer stacks may be replaced by such a MOD processed film.

Carrier lifetime degradation in crystalline silicon solar cells under illumination with white light is a frequently observed phenomenon. Two main causes of such degradation effects have been identified in the past, both of them being electronically driven and both related to the most common acceptor element, boron, in silicon: (i) the dissociation of iron-boron pairs and (ii) the formation of recombination-active boron-oxygen complexes. While the first mechanism is particularly relevant in metal-contaminated solar-grade multicrystalline silicon materials, the latter process is important in monocrystalline Czochralski-grown silicon, rich in oxygen. This paper starts with a short review of the characteristic features of the two processes. We then briefly address the effect of iron-boron dissociation on solar cell parameters. Regarding the boron-oxygen-related degradation, the current status of the physical understanding of the defect formation process and the defect structure are presented. Finally, we discuss different strategies for effectively avoiding the degradation.

Mode I steady crack growth was analyzed to determine the toughening due to domain switching in ferroelectric ceramics. A multi-axial, electromechanically coupled, incremental constitutive theory is applied to model the material behavior of the ferroelectric ceramic. The constitutive law is then implemented within the finite element method to study steady crack growth. The effects of mechanical and electrical poling on the fracture toughness are investigated. Results for the predicted fracture toughness, remanent strain distributions, and domain switching zone shapes and sizes are presented. Finally, the model predictions are discussed in comparison discrete switching models and to experimental observations.

Formation and morphology of D022 compound Ni3V in γ face-centered cubic (fcc) matrix phase were investigated to understand fundamentals for controlling microstructure of alloys strengthened by Kurnakov-type geometrically close-packed (GCP) intermetallics. The D022 phase with plate-shaped morphology coherently precipitates in the γ + D022 two-phase region above the T0 line in Ni–V binary alloys. Due to the negative and positive lattice misfits along the a-axis and the c-axis of D022 (δa < 0 < δc), an invariant line exists between the two phases, and the morphology of D022 phase is changeable by controlling the two factors; the misfit strain ratio δc/δa is a decisive factor to determine the habit plane defined by the invariant line and one of the a-axes of D022, whereas the magnitude of |δa| is responsible for the shape of D022 phase with either prism or plate. These findings were extended to Ni–Fe–Nb–V system by partial replacement of Ni and V with Fe and Nb, respectively.

We report a simple modified polymeric precursor route for the synthesis of highly crystalline and homogenous nanoparticles of lanthanum calcium manganese oxide (LCMO). The LCMO phase formation was studied by thermal analysis, x-ray powder diffraction, and infrared spectroscopy at different stages of heating. These nanocrystallites (average particle size of 30 nm) possess ferromagnetic–paramagnetic transition temperature (Tc) of 300 K, nearly 50 K higher than that of a single crystal. The Rietveld analysis of the powder x-ray diffraction data of the nanopowders reveals significant lattice contraction and reduction in unit cell anisotropy-these structural changes are correlated to the enhancement in Tc.

Gold nanorods 100 nm in diameter were grown within polycarbonate membranes as templates by the electrodeposition technique. A low-temperature sulfidation process was used to make gold sulfide nanoshells around the nanorods with a thickness of ∼7 nm. Optical absorption measurements were carried out on sulfide-coated gold nanorods obtained by dissolving the polycarbonate membrane. Several peaks were observed. These were analyzed on the basis of longitudinal and transverse modes of gold nanorods, the core–shell structure of gold–gold sulfide, and the presence of nanoparticles of gold. Theoretical analysis was carried out using a modified Mie scattering formalism. Satisfactory agreement between experimental results and theoretical fits were obtained.

High-temperature oxide melt drop solution calorimetry was used to study the energetics of formation of cubic silicon nitride prepared at high pressure. The standard enthalpy of formation of c-Si3N4 is −776.3 ± 9.5 kJ/mol. The calorimetric measurement of Si3N4 in 3Na2O·4MoO3 solvent was validated by comparing the enthalpy of formation for β–Si3N4 with previous work using alkali borate solvent. The enthalpy of transformation from β– to c-Si3N4 is 80.2 ± 9.6 kJ/mol. This value appears consistent with the observed synthesis conditions, which do not represent reversed equilibrium reactions.

An investigation of Ni–Cu alloys electrodeposited from aqueous bath, using bothdirect current (dc) and pulsed current (pc) deposition techniques, has revealed many interesting features: A modulated structure with typical layer thickness of 90 and75 nm of copper-rich and nickel-rich layers, respectively, is formed in dc plating. A surprising observation was that the modulation direction was parallel to the substrate, unlike in the case of artificial multilayers wherein it is along the growth direction. No such compositional modulations were observed in pc-plating in the present work. Spinodal phase separation, accompanied by L10 ordering, was found to have occurred in the as deposited samples in both the cases. The size of the deposited crystals in both the cases has been found to be in the range of 2.5–30 nm. Detailed high-resolution transmission electron microscopy has shown that the atomic arrangements are nearly perfect right upto the boundaries of the nanosized grains.

This paper presents an investigation on the corrosion behavior of five solders by means of polarization and electrochemical impedance spectroscopy (EIS) measurements. The Sn–9Zn and Sn–8Zn–3Bi solder, in comparison with the Sn–3.5Ag–0.5Cu and Sn–3.5Ag–0.5Cu–9In solder, were tested in 3.5 wt% NaCl solution and 0.1 wt% adipic acid solution, respectively. The Sn–37Pb solder was for reference in this work. The polarization curves indicated that the Sn–9Zn and Sn–8Zn–3Bi solder showed the worst corrosion resistance both in the salt and acid solutions, in terms of corrosion-current density, corrosion potential, linear polarization resistance, and passivation-current density. Meanwhile, the Sn–3.5Ag–0.5Cu solder remained the best corrosion characteristics in both solutions. It was found that due to microstructure alteration, Bi additive to the Sn–9Zn solder improved the corrosion behavior in the salt solution, whereas decreased that in the acid solution. However, the additive of In degraded the Sn–3.5Ag–0.5Cu solder in both solutions. The EIS results agreed well with the noble sequence of the five solders subjected to the two solutions with polarization. The equivalent circuits were also determined. Nevertheless, the four Pb-free solders exhibited acceptable corrosion properties since there was not much difference of key corrosion parameters between them and the Sn–37Pb solder.

Nano-sized Bi2V0.9Cu0.1O5.35 powders were synthesized via a mechanochemical route from the component oxide mixture. However, a ball-milling duration of over 30 h was needed to ensure a high phase purity. Otherwise, the milled samples had poor sinterability and low sintered density since expansion occurred during sintering.

Mechanical properties and micro-plastic deformation behavior of five bulk metallic glasses (BMGs) were studied by instrumented indentation. These materials included La60Al10Ni10Cu20, Mg65Cu25Gd10, Zr52.5Al10Ni10Cu15Be12.5, Cu60Zr20Hf10Ti10, and Ni60Nb37Sn3 alloys. Remarkable difference in deformation behavior was found in the load–displacement curves of nanoindentation and pileup morphologies around the indents. Serrated plastic deformation depended on the loading rate was found in Mg-, Zr-, and Cu-based BMGs. The subsurface plastic deformation zone of typical alloys was investigated through bonded interface technique using depth-sensing microindentation. Large and widely spaced shear bands were observed in Mg-based BMG. The effect of loading rate on the indentation deformation behaviors in different BMGs was elucidated by the change of shear band pattern.

Experimental investigations by high-resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction show that during sputter-deposition of Ti–B–N films amorphous materials, e.g., TiB2 and BN, are found to precipitate at the grain boundaries, resulting in a decrease in grain size when the boron concentration or the amount of amorphous phase increases. To understand these experimental observations, we have used Monte Carlo simulations to investigate the effect of the amorphous phase precipitation on grain growth during film deposition. Our simulations demonstrate that the precipitation of amorphous phase at the grain boundaries can lower the grain growth exponent and thus leads to a low grain growth rate, particularly in the case of large amounts of amorphous phase. As a result, an exponential decay in grain size with the amount of amorphous phase can be observed in our simulations, which is in reasonably good agreement with the experimental results.

We have studied structure and electrical properties of Si1−YGeY:H films deposited by low-frequency plasma-enhanced chemical vapor deposition over the entire composition range from Y = 0 to Y = 1. The deposition rate of the films and their structural and electrical properties were measured for various ratios of the germane/silane feed gases and with and without dilution by Ar and by H2. Structure and composition was studied by Auger electron spectroscopy (AES), secondary ion mass spectroscopy (SIMS), and Fourier transform infrared (FTIR) spectroscopy. Surface morphology was characterized by atomic force microscopy (AFM). We found that the deposition rate increased with Y, maximizing at Y = 1 without dilution. The relative rate of Ge and Si incorporation is affected by dilution. Hydrogen preferentially bonds to silicon. Hydrogen content decreases for increasing Y. In addition, optical measurements showed that as Y goes for 0 to 1, the Fermi level moves from mid gap to the conduction band edge; i.e., the films become more n-type. No correlation was found between the pre-exponential and the activation energy of conductivity. The behavior of the conductivity γ-factor suggests a local minimum in the density of states at E ≈ 0.33 eV for the films grown with or without H-dilution and E ≈ 0.25 eV for the films with Ar dilution.

We have studied the preparation of silver-gold alloy nanoparticles based on the phase transfer of metal precursors from aqueous phase to organic solution by a fatty amine at room temperature. Silver-gold nanoparticles were synthesized with different molar ratios (2:1, 1:1, 1:2). Ultraviolet-visible absorption spectra suggested the formation of alloy phases. The elemental Ag:Au ratios in the bimetallic nanoparticles determined by energy dispersive x-ray analysis (EDX) were consistent with the Ag:Au molar ratios used in the feeding solution. Transmission electron microscopy (TEM) revealed the formation of a uniform size distribution of Ag:Au nanoparticles (around 5 nm). X-ray photoelectron spectroscopy (XPS) showed that the composition in the outer part of the Ag:Au nanoparticles was similar to that obtained by EDX analysis, which indicates the formation of homogeneous silver-gold nanoparticles. Silver-gold alloy nanoparticles on a gram scale can be obtained with this method.

Here we demonstrate the synthesis of a new type of layered poly(3,4-ethylenedioxy- thiophene) (PEDOT)/MoS2 nanocomposite via flocculation of delaminated MoS2 with subsequent in situ oxidative polymerization of 3,4-ethylenedioxythiophene. The resulting nanocomposite was characterized by Fourier transform infrared spectroscopy, powder x-ray diffraction, x-ray photoelectron spectroscopy, thermal analysis, transmission electron microscopy, and four-probe electrical conductivity measurements with respect to temperature. X-ray diffraction results indicated that the exfoliated MoS2 and PEDOT are restacked to produce a novel nanoscale composite material containing alternate nanoribbons of PEDOT in between MoS2 with a basal distance of ∼1.38 nm. The nanocomposite, which could be used as a cathode material for small power rechargeable lithium batteries, has also been demonstrated by the electrochemical insertion of lithium into the PEDOT/MoS2 nanocomposite, where a significant enhancement in the discharge capacity is observed, compared to that of respective pristine molybdenum disulfide.

Gd-doped ceria solid solutions have been recognized to be leading electrolytes for use in intermediate-temperature fuel cells. In this paper, the preparation, solubility, and densification of Gd0.1Ce0.9O1.95 ceramics derived from carbonate co-precipitation are reported. The dissolution of Gd2O3 in CeO2 lattice was identified to be completed during the co-precipitation process by studying the lattice parameter as a function of temperature. After calcination at 800 °C for 2 h, the nano-sized Gd0.1Ce0.9O1.95 powder (∼33 nm) with a nearly spherical shape and a narrow particle-size distribution was obtained. This calcined powder has high sinterability and maximum densification rate at ∼1000 °C. Sintering at 1300 °C for 4 h yielded over 97% relative density with near maximum. The grain size increased with increases in sintering temperature. The ionic conductivity of these pellets was tested by alternating current impedance spectroscopy to elucidate the contribution of intragranular and intergranular conductivity to the total ionic conductivity. It was found that sintering temperature does not affect intragranular conductivity, though intergranular conductivity was strongly influenced by grain size, grain boundary area, and relativity density. This pellet sintered at 1500 °C for 4 h showed a high ionic conductivity of 5.90 × 10−2 s/cm when measured at 750 °C. The characterization and structural evaluation of the as-received powders were carried out using x-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller, and dilatometer and impedance analysis.

A borate glass, phosphate glass, and silicate glass were converted to hydroxyapatite (HA) by soaking the substrates in a solution of K2HPO4 with a pH value of 9.0 at 37 °C. The weight loss of the substrates was studied as a function of time. Unlike the silicate glasses, the reaction processes of the borate glasses and phosphate glasses were bulk dissolution. X-ray diffraction and scanning electron microscopy revealed an initially amorphous product that subsequently crystallized to HA. The data suggest good bioactive characteristics for the borate and phosphate glass and the potential use of them as a favorable template for bone-tissue formation.

Size-tuned ZnO nanorod arrays (NRAs), aligned well vertically and laterally, were synthesized by catalyst-free, metalorganic chemical vapor deposition on GaN-buffered Al2O3 (0001) substrates by adjusting the O/Zn precursor ratio in the reactor. Their electrical transport properties were investigated using field effect transistors based on individual ZnO nanorods. We find that the carrier concentrations and mobilities in the nanorods are not very sensitive to the change of the precursor ratio. This suggests that altering the precursor ratio is a way of fabricating size-tuned ZnO NRAs with quite consistent electrical properties.

Three-dimensional simulations for relieving the current crowding effect in solder joints under current stressing were carried out using the finite element method. Three possible approaches were examined in this study, including varying the size of the passivation opening, increasing the thickness of Cu underbump metallization (UBM), and adopting or inserting a thin highly resistive UBM layer. It was found that the current crowding effect in the solder bump could be successfully relieved with the thick Cu UBM or with the highly resistive UBM. Compared to the solder joint with Al/Ni(V)/Cu UBM, for instance, the maximum current density in a solder bump decreased dramatically by a factor of fifteen, say from 1.11 × 105 A/cm2 to 7.54 × 103 A/cm2 when a 20-μm-thick Cu UBM was used. It could be lowered by a factor of seven, say to 1.55 × 104 A/cm2, when a 0.7-μm UBM of 14770 μΩ cm was adopted. It is worth noting that although a resistive UBM layer was used, the penalty on overall resistance increase was negligible because the total resistance was dominated by the Al trace instead of the solder bump. Thermal simulation showed that the average temperature increase due to Joule heating effect was only 2.8 °C when the solder joints with UBM of 14770 μΩ cm were applied by 0.2 A.

Two cubic boron nitride (c-BN) thin films (thickness, 80 nm), which were grown on silicon by mass-selected ion beam deposition and thin diamond film-coated silicon by magnetron sputtering technique respectively, were investigated by x-ray absorption near-edge spectroscopy (XANES) at the B K-edge. The angular dependences of the XANES recorded in fluorescence yield (FY) were used to show that the preferable orientation of the sp2-bonded turbostratic BN (t-BN) basal planes at the interfacial layers between the top c-BN film and Si substrate is normal or nearly normal to the substrate, which is consistent with previous transmission electron microscope analysis. The angular dependence was also used to show that the film deposited on diamond-coated Si has a higher relative amount of ordered t-BN at its film-substrate interface than the film on Si substrate. This work that shows a technique to determine the thin film structure, especially the interfacial structure between the thin films and their substrates x-ray absorption fine structure is a powerful mode.