We report the characterization of white light emitting devices fabricated using conjugated polymer blends. Blue emissive poly[9,9-bis(4′-n-octyloxyphenyl)fluorene-2,7-diyl-co-10-(2′-ethylhexyl)phenothiazine-3,7-diyl] [poly(BOPF-co-PTZ)] and red emissive poly(2-(2′-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene) (MEH-PPV) were used in the blends. The inefficient energy transfer between these blue and red light emitting polymers (previously deduced from the photoluminscence (PL) spectra of the blend films) enables the production of white light emission through control of the blend ratio. The PL and electroluminescence (EL) emission spectra of the blend systems were found to vary with the blend ratio. The EL devices were fabricated in the indium tin oxide [poly(3,4-ethylenedioxy-thiophene)-poly(styrenesulfonate)] (ITO/PEDOT-PSS)blend/LiF/Al configuration, and white light emission was obtained for one of the tested blend ratios.

Thin films with a nominal composition close to Ti62.5Si37.5 were deposited on NaCl substrate at room temperature by pulsed laser ablation to study the evolution of the intermetallic compound Ti5Si3 using a combination of high-resolution and in situ transmission electron microscopy. The as-deposited amorphous films contain Ti-rich clusters, which influence the phase evolution and the decomposition behavior of the amorphous film. These clusters influence the nucleation of a metastable fcc Ti solid solution (ao = 0.433 nm) with composition richer in Ti than Ti62.5Si37.5 as the first phase to crystallize at 773 K. The Ti5Si3 nanocrystals form later, and even at 1073 K they coexist with fine fcc Ti-rich nanocrystals. Subsequent Ar+ ion-milling of the crystallized film results in a loss of silicon. The composition change leads to the dissolution of the Ti5Si3 nanocrystals and evolution of a new metastable Ti-rich fcc phase (ao= 0.408 nm).

The structure of hypoeutectic, hypereutectic, and eutectic Ti–Fe alloys produced in the shape of arc-melted ingots was found to consist of the ordered Pm-3m TiFe and disordered BCC Im3m β–Ti solid solution phase. The dimensions of the ingots were about 25–40 mm in diameter and 10–15 mm in height, and their structure was studied by x-ray diffractometry and scanning electron microscopy. The rectangular parallelepiped-shaped samples 2.5 × 2.5 × 5 mm in size cut from the central part of the ingots exhibit a high strength of about 2000 MPa, except for Ti60Fe40, and a certain ductility. The relatively low density of Ti (4.5 Mg/m3) implies high strength/density ratio for the studied alloys. These alloys are characterized by the low cost of the alloying element Fe and, compared to most of the high-strength non-equilibrium materials, do not require additional injection mold casting or rapid solidification procedures.

Carbon nitride powder with an atomic N/C ratio of 1 has been prepared by reaction of cyanuric chloride with sodium metal. X-ray diffraction, Fourier transform infrared spectra, and x-ray photoelectron spectroscopic data provide substantial evidence for a graphite-like sp2-bonded structure composed of building blocks of s-triazine rings bridged by carbon-carbon atoms in the bulk carbon nitride. The electron-microscopy results reveal that the material is spherical particles with an average diameter of 50 nm. The optical properties and thermal stability are also characterized. Based on the experimental results, it is deduced that the structure of as-prepared material carbon nitride has polyether structure.

The effect of the doping by compounds with bivalent and trivalent cations (BN, Al2O3, MgO + SiO2) on the diffuse reflectance spectra (ρλ) and the integral solar absorptance (as) and their changes at irradiation (with 30 keV electrons, 3 keV protons, and electromagnetic radiation that imitates solar spectra) of the reflecting thermal control coatings based on ZrO2 powders is examined. The coating based on untreated ZrO2 pigment and the coatings based on the pigments treated with 1 and 3 mass% of Al2O3 nanopowder were subjected to simultaneous action of electrons, protons, and electromagnetic radiation that imitates action of these irradiations on geostationary satellite orbit. After that, the comparative investigations of the changes in spectral reflectance and solar absorptance of these coatings were carried out.

The mechanical testing technique for in situ nanoindentation in a transmission electron microscope is described and is shown to provide real-time observations of the mechanisms of plastic deformation that occur during nanoindentation. Here, the importance of this technique was demonstrated on an aluminum thin film deposited on a single-crystalline silicon substrate. Significant results include direct observation of dislocation nucleation, characterization of the dislocation distribution created by indentation, and the observation of indentation-induced grain boundary motion. The observations achieved by this technique provide unique insight into mechanical behavior studied with conventional instrumented nanoindentation techniques and also provide microstructural-level understanding of the mechanics of ultrasmall volumes.

A comprehensive approach is presented for defining hydrogen activation and absorbing kinetics in heterogeneous Mg2Ni/Ni powder composites that were subjected to mechanical refinement. Hydriding tests were performed under conventional hydrogen dissolving and under reactive milling. Irrespective of the absorbing mode, the absorption kinetics is deceleratory throughout. Under conventional thermodynamic conditions, the hydriding rate depends strongly on the microstructural features of both the absorbing Mg2Ni intermetallic and the Ni phase. The latter plays an important role in the dissociative chemisorption of hydrogen. Under milling the hydrogen uptake and the hydriding kinetics also depend on the intensity of the milling processing, IM (watt g−1), with the absorption rate increasing exponentially with IM. The mechanical treatment was found effective even when thermodynamic absorption reached saturation level. Hydriding rates, mechanochemical gains, and instantaneous mechanochemical yields (mol J−1) were used to compare the processes on an absolute scale and to spotlight possible mechanisms controlling kinetics trends and absorbing features under milling.

Isothermal crystallization kinetics of amorphous Ga–Sb–Te films was studied by means of a time-resolved optical transmission method. Thin films with compositions along the pseudo-binary tie-lines Sb7Te3–GaSb and Sb2Te3–GaSb in the ternary phase diagram were prepared by the co-sputtering method. Crystallization of GaSbTe films reveals a two-stage process: an initial surface nucleation and coarsening (Stage 1) followed by the one-dimensional grain growth (Stage 2). The kinetic exponent (n) value in Stage 1 shows strong dependence on film compositions, while that of Stage 2 is less dependent. The activation energy in Stage 1 increases with increasing GaSb content and reaches the maximum values at compositions close to GaSb, but a decreasing trend was observed in Stage 2. Kinetics parameters between isothermal crystallization of thin films and non-isothermal crystallization of powder samples analyzed by differential scanning colorimetry [J. Mater. Res. 19, 2929 (2004)] are compared. The kinetic parameters in Stage 1 show much correspondence with those of non-isothermal cases in comparable kinetic exponents but with lower activation energies. The discrepancies between nonisothermal and isothermal kinetics are attributed to the sample morphology and the constraint effects.

Stress-induced migration is one of the problems related to the reliability of metal interconnections in semiconductor devices. This phenomenon generates voids and disconnections in the metal interconnections. The purposes of this work are to establish the stress-induced model based on atomic migration and theoretically clarify the temperature characteristics of void formation and disconnection using the presented model. First, the stress-induced migration model based on atomic migration in which the driving force is the gradient of elastic potential is presented. Next, to clarify the temperature characteristics of stress-induced migration, the presented model is applied to the formation of voids and disconnections and the results of theoretical analyses are compared with experimental results. It was found that the temperature characteristics of the void formation show various patterns depending on the void interval, and the temperature characteristics of the disconnection show various patterns depending on the void interval and void radius. These theoretical results are in agreement with the experimental results.

This study investigated the vibration fracture properties of Sn–Ag–Cu alloys with various Cu contents. Results show that the microstructure becomes finer with a higher Cu content. This leads to a lower damping capacity, higher deflection amplitude, and thus inferior vibration fracture resistance under a constant vibration force. It is of interest that when the Cu content reaches 1.5 wt%, the specimen possesses the highest damping capacity and greatest vibration life. The presence of massive primary Cu6Sn5 intermetallics probably accounts for this phenomenon.

The tin–silver–copper eutectic is a three-phase eutectic consisting of Ag3Sn plates and Cu6Sn5 rods in a (Sn) matrix. It was thought that the two phases would coarsen independently. Directionally solidified ternary eutectic and binary eutectic samples were isothermally annealed. Coarsening of the Cu6Sn5 rods in the binary and ternary eutectics had activation energies of 73 ± 3 and 82 ± 4 kJmol-1, respectively. This indicates volume copper diffusion is the rate controlling mechanism in both. The Ag3Sn plates break down and then coarsen. The activation energies for the plate breakdown process were 35 ± 3 and 38 ± 3 kJmol-1 for the binary and ternary samples respectively. This indicates that tin diffusion along the Ag3Sn/(Sn) interfaces is the most likely the rate-controlling mechanism. The rate-controlling mechanisms for Cu6Sn5 coarsening and Ag3Sn plate breakdown are the same in the ternary and binary systems, indicating that the phases evolve microstructurally independently of one another in the ternary eutectic.

Lead titanate (PbTiO3) is a ferroelectric/piezoelectric material widely used in medical ultrasound transducers and infrared detectors. It is also important as an end member of morphotropic solid-solution systems such as Pb(Zn1/3Nb2/3)–PbTiO3 (PZN–PT) and Pb(Mg1/3Nb2/3)–PT (PMN–PT) that exhibit exceptional electromechanical properties as oriented single crystals. The float-zone technique has been used to grow pure crystals of lead titanate. To the best of the authors’ knowledge, this is the first time that the growth of this compound by the float-zone technique has been reported. The principal advantage of the float-zone technique is that no container is required so that a uniform distribution of chemical constituents can be obtained while eliminating problems of heterogeneous nucleation and metal contamination at the container wall. Although large single crystals were not obtained in the current study primarily due to instabilities of the molten liquid zone, the combined results of characterization by electron probe microanalysis, x-ray diffraction, specific heat, and dielectric permittivity measurements show that the float-zone crystal growth technique can produce lead titanate crystals of high chemical and phase purity. However, the results show that to obtain large single crystals, the stability of the molten zone at low cooling rates must be improved.

The load-bearing capacity of self-lubricating W–S films can be improved by doping with nitrogen or carbon. In this study, the chemical composition, the atomic bonding, the structure, and the surface and cross section morphologies of sputtered W–S–C(N) films were analyzed. The addition of the doping element leads to a progressive broadening of the x-ray diffraction (XRD) peaks indicating a loss of crystallinity. In W–S–N films, amorphous structure could be obtained. In W–S–C films, W–C compounds were detected in conjunction with the hexagonal WS2 phase. For the highest C contents, a nanocomposite structure, including those phases and graphite, was suggested for the film. X-ray photoelectron spectroscopy results showed different types of bonds in the W4f peak in good agreement with the XRD results, i.e., when W–C(N) compounds were indexed W–S, W–C, and W–N bonds are present in the W4f peak. For the highest C content film, the detection of C–C bond in the C1s peak confirmed the formation of graphite.

Diamond-like carbon films were synthesized by electro-deposition technique from an organic liquid (a solution of alpha- and beta-pinenes in n-hexane) on silicon substrate at room temperature and at room pressure. The x-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectra, Raman spectra, photoluminescence (PL), and x-ray absorption near edge structure (XANES) spectra analysis were used to study the properties of the diamond-like carbon (as-deposited and annealed) films. The XRD measurement indicated that the film contains some diamond-crystalline phases whereas Raman spectra did not show any prominent diamond-like peak. PL intensity as higher for the as-deposited film and decreased with high-temperature vacuum annealing. FTIR spectra showed the presence of sp3 hybridization C–H bonds and their intensity decreases at higher annealing temperature. C and O K-edge XANES spectra showed that π* (sp2) intensity significantly decreases when the annealing temperature is 600 °C.

The distinctive finding of unstable displacement bursts of indent depth observed in nanoindentation is thought to be linked to the dislocation emission phenomenon. However, because of a lack of understanding of the surface physics of the contact area, the explanation of the instability mechanism remains vague. In this paper, an effect of the surface roughness on the displacement bursts was experimentally investigated using single-crystalline aluminum. The surface properties of samples with several degrees of roughness of less than 10 nm were measured using atomic force microscopy. The discussion focuses on the relations between critical values of the load at the displacement bursts and the burst width.

Nanocrystalline BaTiO3 particle–polymer hybrid was synthesized by polymerization and hydrolysis of [2-(methacryloxy)ethoxy]triisopropoxytitanium (MEPT) and barium alkoxide. The precursor for hybrid was synthesized from prepolymerized MEPT and barium alkokide, which was then hydrolyzed to form BaTiO3 particle–polymer hybrids below 100 °C. BaTiO3 particles increased in crystallinity when the amount of water for hydrolysis increased. The nanocrystalline particles were identified to be BaTiO3 by electron diffraction. Nanometer-sized BaTiO3 particle–polymer hybrid was shaped to a film with a dielectric constant of 8.2 at 10 kHz. A suspension consisting of the hybrid and silicone oil responded to a direct-current field, exhibiting a typical electrorheological behavior.

The friction and wear behavior of Si3N4-based composites against AISI-52100 steel were investigated in the ball-on-disk mode in a nonlubrication reciprocation motion. It has been found that under the conditions used, all the ceramic components exhibited rather low friction and wear coefficients. For monolithic silicon nitride materials, high friction coefficients between 0.6 and 0.7 and wear coefficients between 1.63 × 10−8 and 1.389 × 10−6 mm3/N · m were measured. The contact load was varied from 100 to 300 N. By adding titanium nitride, the friction coefficients were reduced to a value between 0.4 and 0.5 and wear coefficients between 1.09 × 10−8 and 0.32 × 10−6 mm3/ N · m at room temperature. All materials and worn surfaces as well as wear debris were investigated by means of scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, and transmission electron microscopy (TEM) before or after the tribological tests. The TEM micrographs of wear track revealed plastic deformation through twins and cracking along grain boundary which play an important role in the fracture mechanism.

Hexagonal graphitic BN (h-BN) is interesting as a second phase for high-temperature structural ceramics because it has the same crystal structure as graphite, for which fracture strength and Young’s modulus increase with increased temperature. In this study, high-temperature mechanical properties of Si3N4/BN nanocomposite were evaluated to clarify the effect of fine h-BN particles at elevated temperatures. As a result, we found that high-temperature strength and hardness of the nanocomposite were maintained up to high temperatures; also, its Young’s modulus increased gradually, concomitant with elevated temperatures up to 1400 °C. Finally, these properties were compared with those of monolithic Si3N4 and Si3N4/BN microcomposite.

The direct current (dc) conductivities and organic field-effect transistor (OFET) characteristics of a class of octa-substituted liquid crystalline (discotic mesophase) phthalocyanines (Pcs) are discussed. These molecules self-organize into columnar aggregates with large coherence lengths (up to approximately 300 nm). Langmuir–Blodgett films of these molecules were horizontally transferred to either interdigitated microelectrodes (IME) or OFET substrates, so that current flow could be measured either parallel or perpendicular to the column axis. Twenty-eight bilayer films of these Pcs on the IME substrates showed anisotropies in dc conductivity up to 50:1, whereas similar Pc films showed anisotropies in field effect mobilities of approximately 10:1, for a variety of W/L ratios (source/drain dimensions and spacing). Field-effect mobilities of 1 to 5 × 10-6 cm2·V-1·s-1 were determined from OFET measurements, along the Pc column axis, whereas charge mobilities measured from the space charge limited current regime on the IME substrates were in the range of 10-4 cm2·V-1·s-1. Conductive tip atomic force microscopy measurements on the apprximately 500-nm length scale showed that the conductivity anisotropy can be as high as 1000:1 when the Pc columns are intimately contacted to an adjacent Au bond pad.

A low-temperature (320–480 °C) metal-organic chemical vapor deposition (MOCVD) process was developed for the growth of ruthenium and ruthenium oxide thin films. The process used bis(ethylcyclopentadienyl)ruthenium [Ru(C5H4C2H5)2] and oxygen as, respectively, the ruthenium and oxygen sources. Systematic investigations of film formation mechanisms and associated rate limiting factors that control the nucleation and growth of the Ru and RuO2 phases led to the demonstration that the MOCVD process can be smoothly and reversibly modified to form either Ru or RuO2 through simple and straightforward modifications to the processing conditions–primarily oxygen flow and substrate temperature. In particular, films grown at low oxygen flows (50 sccm) exhibited a metallic Ru phase at processing temperatures below 480 °C. In contrast, films grown at high oxygen flow (300 sccm) were metallic Ru below 400 °C. Above 400 °C, a phase transition was observed from Ru to RuOx (0 < x < 2.0) to RuO2 as the processing temperature was gradually increased to 480 °C.