Microwave dielectric properties of the solid solution between Ba(Ni1/3Nb2/3)O3 and Ba(Zn1/3Nb2/3)O3 were investigated. Samples were prepared by the conventional mixed oxide method as well as the Pechini method. Sintered samples were analyzed using x-ray diffraction and scanning electron microscopy, and their microwave dielectric properties were measured by the post resonator method. The sample prepared by the Pechini method revealed excellent dielectric properties, i.e., permittivity of 35.6, quality factor of 5700 at 10 GHz, and very small temperature coefficient of resonant frequency. Order-disorder behavior of this solid solution system was found to depend on processing parameters. Variation in microwave dielectric properties was discussed in terms of the order-disorder behavior, chemical composition, mixture rule, etc.

The chemical reactions between hyperthermal species from a methane plasma and the boron nitride surface have been studied. In this work we report an x-ray photoemission study of the boron nitride with varying degrees of carburization. The carbon ions react, forming C–B and C–N bonds; for surface carbon concentration, smaller than ,∼0.30, C–B bonds are formed, while for higher surface carbon concentrations C–N bonds are also observed. In addition, the binding energy difference between the N1s and B1s core levels increases with increasing carbon content of the film. These chemical shifts are interpreted in terms of the decrease of the ionicity of the material as a consequence of the increase in the number of C–B and C–N bonds. For surface carbon concentration higher than 0.30, amorphous carbon is also formed that grows and finally forms a surface layer. The valence band spectra of the BNC compounds show that the density of states filling the gap at about 15 eV between the two characteristic peaks of the valence band of BN, marking the nitrogen 2s orbitals and the boron and nitrogen 2p electrons and the orbital hybridization between the 2s of boron and 2p states, increases with increasing carbon fluence as a consequence of the hybridization with carbon orbitals.

The effect of excess bismuth on the ferroelectric properties of SrBi2Ta2O9 (SBT) thin films having a perovskite-like layered structure was investigated for excess bismuth contents ranging from 0% to 100%. For the first time, a limited solid solution of SBT and Bi2O3 was shown to exist when the amount of excess Bi was less than 50%. The formation of a solid solution enhanced the grain size and a-b plane orientation of the films, resulting in substantial improvement in the ferroelectric hysteresis properties of the films. On the other hand, when the amount of excess Bi exceeded 50%, Bi2O3 appeared as a second phase which led to high leakage current and poor ferroelectric hysteresis curves. 30–50% excess Bi content was found to be the optimum composition with respect to grain size, crystallographic orientation, and single phase formation. Within this range, SBT films exhibit low leakage current density (˜10−9 A/cm2) and maximum remanent polarization (2Pr ˜12 µC/cm2).

Pb(Zr0.52Ti0.48)O3 (PZT) thin film on Pt/RuO2 double electrode was successfully prepared by using a new alkoxide-alkanolamine, sol-gel method. It was observed that the use of Pt/RuO2 double electrode reduced leakage current, resulting in a marked improvement in the leakage characteristics and more reliable capacitors. Typical P-E hysteresis behavior was observed even at low applied voltage of 5 V, manifesting greatly improved remanence and coercivity. Fatigue and breakdown characteristics, measured at 5 V, showed stable behavior, and no degradation in polarization was observed up to 1011 cycles.

Transmission electron energy loss spectroscopy was used to obtain local dielectric properties in barium titanate. The high frequency dielectric function of the material was studied dynamically during the cubic-to-tetragonal (c → t) phase transformation in conjunction with the effect of a small amount (0.9%) of donor dopant (niobium). In order to obtain the local dielectric function during the phase transformation, Kramers–Kronig relations were applied to the energy loss measurements. The optical excitations in the energy loss spectra were consistent with band structure results from the literature. The Re (1/∈), real part of the inverse dielectric function, obtained from the energy loss data indicated a change at the phase transformation. Specifically, a broadening of the valence plasmon excitation is observed which is attributed to the order-disorder nature of the t → c transformation. A 0.4 eV shift in the volume plasmon was observed in the Nb-doped sample in all regions (within grains as well as at grain boundaries), indicating a uniform incorporation of the dopant in the lattice. In this paper, the changes in the dielectric function, such as shifts in collective excitations, are attributed to a large contribution from loosely bound Nb electrons. Furthermore, it is demonstrated that it is possible to obtain local (≈10 nm) physical property of a complex material dynamically at relatively high temperature.

Polycrystalline LSCO/PNZT/LSCO ferroelectric capacitor heterostructures were grown by pulsed laser deposition using a composite conducting barrier layer of Pt/TiN on poly-Si/Si substrate. The growth of the ferroelectric heterostructure is accomplished at a temperature in the range of 500–600 °C. This integration results in a 3-dimensional stacked capacitor-transistor geometry which is important for high density nonvolatile memory (HDNVM) applications. Transmission electron microscopy shows smooth substrate-film and film-film interfaces without any perceptible interdiffusion. The ferroelectric properties and reliability of these integrated capacitors were studied extensively at room temperature and 100 °C for different growth temperatures. The capacitors exhibit excellent reliability, both at room temperature and at elevated temperatures, making them very desirable for HDNVM applications.

Carbon nitride films have been synthesized at low substrate temperature by Ar+ sputtering a graphite target with concurrent N+ assisted bombardment. It was disclosed that N+ bombardment with low energies of 150–400 eV and beam densities of 0.16–0.23 mA cm−2 was favorable to grow carbon nitride films with high N/C atomic composition ratios of 0.47–0.56. The spectra of x-ray photoelectron spectroscopy and infrared spectroscopy show that the low energy N+ bombardment activates nitrogen atoms to combine carbon atoms in unpolarized covalent bonds. Under the 150–300 eV and 0.16–0.23 mA cm−2 N+ assisted bombardment, the formed films are identified by transmission electron microscopy to possess the β–C3N4 microcrystalline structure. The films exhibit an extremely high hardness of 5260 kgf/mm2, a high resistivity of 4.8 × 1012 Ω × cm, and excellent optical transmittance. Friction and wear tests show that carbon nitride films on steel substrate can perform the even wear in low friction coefficients of 0.05–0.16 while raising wear loads up to 20 N.

The mechanism of the 1:1 nonstoichiometric short-range ordering in donor-doped Pb(B′1/3B″1/3)O3-type relaxor perovskites was examined using the La2O3-doped Pb(Mg1/3Nb2/3)O3 (PMN) system as a typical example. Based on the dielectric analysis and the transmission electron microscopy (TEM) observation, the observed increase in the degree of diffuse phase transition (DPT) in the presence of La2O3 was interpreted as the enhancement of the 1:1 nonstoichiometric short-range ordering accompanied with the growth of the negatively charged nanodomains. The mechanism of the defect process responsible for the 1:1 nonstoichiometric short-range ordering was elucidated by analyzing the electrical conductivity of the La-doped PMN system as a function of the partial pressure of oxygen. It was shown that the substitution of La3+ ions for Pb2+ ions in the A-site sublattice of perovskite PMN produced the positively charged sites with a concomitant generation of electrons for the electronic compensation. This expedites the growth of the nonstoichiometrically ordered nanodomains in a disordered matrix.

The diffuse phase transition (DPT) characteristics and the associated defect mechanism of Na-doped Pb(Mg1/3Nb2/3)O3 (PMN) relaxor perovskite were studied. The enhanced DPT and the decrease in the intensity of the superlattice reflection were observed in the presence of Na2O. These contradictory observations were interpreted in terms of the inhibition of the growth of the 1 : 1 nonstoichiometric short-range ordered domains and the increase in the microcompositional fluctuation of the B-site cations caused by the formation of negatively charged Na′Mg sites. The mechanism of the associated defect process was then elucidated by analyzing the electrical conductivity as a function of the oxygen partial pressure. It was shown that the substitution of Na+ ions for Mg2+ ions in the B-site sublattice of perovskite PMN produced the negatively charged sites with a concomitant generation of oxygen vacancies () for the ionic compensation. This expedites the enhancement of the compositional inhomogeneities of the B-site cations and suppresses the growth of the nonstoichiometrically ordered nanodomains in a disordered matrix.

BaTiO3 thin films were deposited by metal-organic chemical vapor deposition at 840 °C on two differently treated (100) MgO single crystal substrates. One MgO substrate was only mechanically polished and the other substrate was polished and then annealed at 1100 °C for 4 h in oxygen. Observation by transmission electron microscopy showed that the BaTiO3 thin film deposited on the unannealed substrate was fine-grained and that the whole film was epitaxial (100) in nature. In contrast, the film deposited on the annealed substrate consisted of large, (100)-oriented, epitaxial grains within which were distributed (110)-oriented grains with random in-plane orientations. These differences in BaTiO3 films deposited on differently treated substrates are discussed with reference to the surface structure of the MgO substrate and nucleation kinetics of BaTiO3 thin films on MgO.

The synthesis and characterization of mesostructured zirconia and titanium oxides are presented. The samples were investigated by x-ray powder diffraction (XRD), transmission electron microscopy (TEM), and atomic force microscopy (AFM). XRD and TEM revealed only lamellar structures for both materials, whereas AFM could detect locally restricted initial stages of cubic or hexagonal phases in a globally lamellar Ti oxide.

A high-resolution electron microscopy study of β–SiC nanoparticles formed by C+-implantation of single crystal silicon with subsequent annealing has been carried out. The as-implanted sample had a trilayered structure, in which the surface layer, A, and the bottom layer, C, were crystalline but damaged, and the middle layer, B, was amorphous. After annealing this structure, β–SiC particles were formed throughout the trilayered structure but with different forms: a few epitaxial β–SiC nanoparticles in layers A and C, and more random nanoparticles in layer B. The β–SiC nanoparticles, in the size range 2–8 nm, should be responsible for the blue-emitting effect of the silicon-based porous β–SiC.

The amount and defect type of substitutional nitrogen in synthetic diamond strongly influences crystal strength. There is an optimum amount of nitrogen that yields the highest compressive fracture strength for crystals derived from common growth conditions. It is postulated that the role of nitrogen is to charge-balance vacancies created during growth. If too little nitrogen exists in the diamond, vacancies are not charge-balanced and may serve as crack initiation and/or propagation sites. Excess nitrogen above that required to charge-balance vacancies may weaken the lattice by adding local strain to the crystal. IR microscopy indicates that most of the substitutional nitrogen in synthetic diamond is increased in the vicinity of the intersections of growth sectors on the crystal surface. Most surface IR-visible nitrogen is biased toward the (111)–(100) intersection. The bias in incorporation of substitutional nitrogen at external growth sector intersections (i.e., edges and corners) of an industrial high-grade saw diamond crystal influences the progression of fatigue by microfracture during cutting of hard stone.

Insulating epitaxially grown SrTiO3 thin films were prepared on (100)MgO substrates by metal-organic chemical vapor deposition (MOCVD). Semiconductive SrTiO3 thin films were obtained by the rapid cooling after reheating in reduction atmosphere. The microstructure, crystal structure, and electrical properties of these films were investigated. The electrical properties varied by the composition of films and heat-treatment conditions, i.e., the heating temperature, the oxygen partial pressure, and the cooling rate after the annealing. Change of the resistivity of the film was attributed to that of the carrier concentration. Mobility of films was unchanged, and the value was almost the same order of that of bulks. The lowest resistivity of 0.1 Ω·cm was obtained when a sample of Ti/Sr = 1.0 was heated at 1200 °C under 10−15 Pa of PO2 and then rapidly cooled. This value is similar to that of bulks (100 –10−1 Ω · cm).

The samples of Upilex R polyimide (PI) were irradiated with 90 keV N+ ions to the fluences from 5 × 1014 to 2 × 1017 cm−2, and sheet resistance (Rs) and thermoelectric power (TEP) were measured in dependence on the ion fluence and the sample temperature. The Rs achieves its minimum for the ion fluence of 1 × 1017 cm−2, and from the measured temperature dependence of Rs it may be concluded that the ion beam modified PI exhibits semiconductor properties with charge transport governed by the variable range hopping mechanism. The measured TEP of the PI samples irradiated to the fluences above 1 × 1016 cm−2 is low (the order of μV/K). Such properties are typical for metals, and the conclusion is that the charge transport in the irradiated PI samples is contributed by the mechanisms which are characteristic for both semiconductors and metals. The role of conjugated double bonds was examined by measuring absorption UV-VIS spectra. The number of the conjugated double bonds correlates with observed Rs, and the width of the forbidden band, determined from UV-VIS spectra, is a decreasing function of the ion fluence.