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The effect of dislocations, grain boundaries and bulk recombination on minority carrier lifetime in multicrystalline silicon were studied by developing a new model. Minority carrier lifetime was measured using the carrier density imaging (CDI) technique, grain boundaries were then mapped and characterized by electron backscatter diffraction (EBSD) and sub grain boundaries were found to be recombination active and dominating the number of active grain boundaries.

Interface motion and equilibrium were studied within the setting of a one-dimensional chain of harmonic oscillators. The interface demarcates regions of differing elastic stiffness and accretes through isothermal fluctuation theory, while the motion of each mass is governed by a simple force balance.

The stress gradients in CrN films are described by the net sum of three contributions, which includes tensile stress, compressive stress and thermal stress. The tensile stress due to grain boundaries depends on the height in the film, the thermal tensile stress is not dependent on film thickness and compressive stress is caused by ion peening.

X-ray diffraction mapping is used to show concave crystal plane curvature in silicon carbide substrates from five commercial suppliers with two suppliers producing wafers with

A report on fine-grained polysilicon layers with a grain size of only 0.1-0.2 [mu]m that shown an open-circuit voltage of 536 mV is presented. Phosphorus spikes along the grain boundaries enhance the junction area and determine the collection and the recombination volumes.

The Nd self-diffusivity is studied in nanocrystalline Nd-rich Nd2Fe14B. Grain-boundary diffusion coefficients D(super Nd)(sub GB) are derived from the analysis of the diffusion profiles.

A simple method to estimate the effective biaxial modulus of cubic polycrystalline films with an arbitrary [hkl] fiber texture is presented. For an arbitrary [hkl] fiber axis, analytic expressions are given for the Voigt and Reuss bounds, followed by proving that these two bounds coincide if, and only if, the fiber axis is equivalent to [100] or [111] when the constituent grains are anisotropic.

The article, on the basis of the Boltzmann equation, proposes a model that includes scattering from both film surfaces and grain boundaries. The quasiclassical electrical transport in metallic films is studied.

Issues are presented concerning the research which has been carried out into superconductor bicrystal grain boundaries. The use of thin films of high-temperature cuprates in superconducting quantum interference devices is discussed.

Grain boundary migration effects on hillock formation in AI thin films is examined.

The Sigma3(111) grain boundary in tungsten was studied to simulate the properties and show the effects of many-body interactions on grain boundary resistance.

The built-in field produced by charged grain boundaries between crystalline blocks in bulk and thin films was investigated.

X-ray photoelectron spectroscopy (XPS) was used in determining the grain boundary diffusion of titanium through platinum thin films. Results indicate that diffusion is a function of film thickness when the latter goes beyond 200 angstroms. The diffusion kinetics remains constant when the thickness is higher than 200 angstroms and when the temperature varies from 200 to 600 degrees C. Alloy formation was not detected since there was no observable shift in the XPS Pt peak position.

Research was conducted to examine both current-voltage (I-V) and capacitance-voltage (C-V) characteristics in Nb-doped BaTiO3 bicrystals to verify the potential barrierd model. Device simulation analysis illustrates that potential barrier with a semiconductor-insulator-semiconductor structure can consistently interpret the observed characteristics rather than the double Schottky barrier. Results show that the low-frequency excess capacitance observed even at zero bias is attributed to the spatial distribution of the acceptor states in the insulating layer.

Research was conducted to examine thin films of La0.67Ca0.33MnO3 on SrTiO3 bicrystal substrates which were prepared using pulsed laser ablation. Full epitaxial growth was shown by X-ray diffraction on both sides of the bicrystal substrate. The low- and high-field magnetoresistance was measured as a function of magnetic field, temperature and current. An explicit dependence of the spin polarization on the applied current in the grain boundary region is proposed.

A detailed low temperature magnetic investigation of Fe(sub x)Rh(sub 100-x)fcc nanocrystalline alloys derived by ball milling with Fe contents within the range (26

Research was conducted to examine the electrically active grain boundary structure of ZnO polycrystals using a combination of scanning electron microscopy (SEM) and scanning tunneling spectroscopy (STM). Reduced surface band gaps were observed through current imaging tunneling spectroscopy at the charged boundaries imaged by SEM-based remote electron beam induced current (REBIC). REBIC contrasts in SEM and STM images are not comparable due to the different excitation conditions and signal generation volume of each method.

Research was conducted to examine a simple kinetic analysis of interfacial diffusion accompanied by intermetallic compound formation. The kinetics of compound formation were added based on Fisher's grain boundary diffusion model which led to the development of an analytical solution. The solution was compared to experimental data calculated from the penetration of the solder along the electroless Ni interface.

A study was conducted to analyze the transport characteristics of artificial grain boundaries formed in different thin films prepared on bicrystal substrates. Current-voltage curves were determined by applying a low frequency sinusoidal current as a function of magnetic field and temperature. Experimental results indicated that magnetoresistance may be unrelated to tunneling.

Research was conducted to examine the dynamics of grain growth and the pinning effect of grain boundaries on magnetic domain walls in FeCo soft magnetic alloys. Grain growth was observed to occur at temperatures above 600 degrees C. By keeping the same ordering parameter for all samples investigated, the effect of grain size on magnetic properties was determined. Results also demonstrate that grain boundaries serve as pinning sites for the magnetic domain wall movement.

Grain boundary wetting can provide useful electrical and mechanical properties in grain boundaries of many solids yet the kinetic mechanism of grain boundary wetting remains ambiguous. A study therefore describes observations of grain boundary wetting in metals made under relatively controlled conditions. Among other results, the kinetics of stress relaxation and the role of atomic penetration ahead of the groove root in the grain boundary wetting kinetics require further studies.

Scanning and transmission electron microscopies and atomic force microscopy were used to characterize the topography and crystallography of YBa2Cu3O7-d bicrystal films deposited on SrTiO3 bicrystals. The results of the study reveal that crystal misorientation as well as boundary inclination can differ substantially in terms of the fixed macroscopic bicrystal parameters. It is theorized that the variations account for the gap between predicted and observed junction behavior.

Research was conducted to examine critical current in high Tc grain boundary junctions. The objective is to prove that semiconductor junctions have a S-alpha-N-beta-I-N-beta-S-alpha structure and that grain boundary junction critical current density Jc is related to reduced normal resistance. Results demonstrate that many natural and artificial grain boundaries have a S-alpha-N-beta-I-N-beta-S-alpha structure which has a wide applicability to the study of YBCO grain boundary physics.

A least squares fitting procedure, GBFIT, is described which analyzes data from the tail regions of diffusion profiles to the Whipple/Suzuoka equations for grain boundary. Basic equations were extended to include diffusion within the gain boundary so that the GBFIT can be applied to Harrison's type B and/or C kinetics. Examples of the use of GBFIT are shown in which experimental diffusion profiles in polycrystals and bicrystals are examined.

A Monte Carlo simulation that factors in the electrostatic and configurational energies associated with charges at the grain boundary is used to calculate the equilibrium charge density and free energy of tilt grain boundaries as a function of their misorientation. Results show that equilibrium charge density increases with the grain-boundary angle and nears a saturation value. At large-angle grain boundaries, the equilibrium charge density closely matches experimental values for large-angle tilt boundaries in GaAs.

Computational methods were employed in the examination of the role of ideal grain boundaries in composite-type permanent magnets. Results verify the importance of ideal intergranular exchange interaction in obtaining a sufficiently high coercivity and high remanence. The linear dependences of remanence for a 20 nm mean grain diameter and a 50% alpha-iron volume fraction were also determined.

Research was conducted to examine the influence of temperature and interface charge on the grain-boundary conductivity in acceptor-doped SrTiO3 ceramics using a numerical simulation technique. The potential barrier's temperature behavior at the grain-boundary core and the theoretical explanation for the behavior are presented. Results indicate that the electrical characteristics of the grain boundaries can be influenced deliberately by decorating the grain boundaries with suitable dopants.

A model is proposed for polycrystalline semiconductor grain-boundary-limited conduction. The model represents a coefficient of current nonuniformity, the bulk parameters mean free path and carrier effective mass, the grain boundary parameters barrier width and height. It was found to consistently interpret Hall measurements and temperature conductivity in polycrystalline SnO2 thin films with various Sb concentrations.

A study was conducted on the characterization and synthesis of Nd2Fe14B-25 bol % Fe nanocomposite magnets. The milling time and heat treatment temperature required for synthesis were optimized by enhancing the volume fractions of hard and soft spaces. Microstructural characterization shows that grain growth occurs and magnetic properties deteriorate at high treatment temperatures.

A hybrid approach which combines titanium magnetron sputtering and graphite laser ablation was used in synthesizing nanocrystalline TiC/amorphous carbon composite films at near room temperature. Transmission electron microscopy, x-ray diffraction analyses and x-ray photoelectron spectroscopy were employed in examining the film microstructure. The films were made up of 10 nm sized TiC crystallites inside a sp3 bonded a-c matrix and exhibit a 32 GPa hardness and excellent plasticity.

The radio frequency sputtering method was employed in preparing Cd1-xNixTe nanostructured thin films formed with spherical-like microcrystallites with broad grain size distribution. Films with adverage diameters of 26, 30 and 35 nm exhibited Ni concentrations of 15%, 10% and 5%, respectively. Results also reveal that grain size declines and the optical band gap energy exhibits a 7.5 meV/at % as the films' Ni content enhances.

A study was conducted on the different approximations to the Whipple model for grain boundary diffusion. Approximations include those for calculating grain boundary diffusivity from experimental data. An algorithm was proposed for avoiding the approximations. Results reveal that the algorithm is robust despite the presence of moderate experimental error and that it can be used to reduce the influence of such errors.

The result of the study of the interaction of iron with the grain boundary in boron-doped multicrystalline silicon shows the formation of a well-defined iron depletion layer of length 20 micro meters around the grain boundary. The electron-beam-induced-current technique is used to contaminate the sample with iron. The diffusion length of the iron related carriers shows a temperature dependence and this confirms the formation of a new recombination channel.

Undoped amorphous-Si (a-Si) films are deposited as a function of deposition temperature on fused quartz substrates by low pressure chemical vapor deposition using 100% disilane. The texture of these poly a-Si films is significantly influenced by the deposition temperature of the initial films which serve as the substrates. The films grown below a temperature of 530 degrees Celsius exhibit a dominant (100) texture and beyond this temperature, a (111) texture. A decrease in deposition temperature results in a reduction of the nucleation rate.

Analysis of defect development and crystal growth in amorphous silicon thin films by examining the solid phase crystallization of the films using high-resolution transmission electron microscopy reveals that the grains have a dendritic or elliptical shape and display extrinsic and intrinsic stacking faults and extended screw, perfect and Shockley dislocations. Defects in the stacking sequence of the amorphous crystalline interface, crystal growth front intersection and twin plane jumps are responsible for the faults in the grains. The stacking faults and twins enhance grain growth in the (112) direction.

An analysis of the correlation between temperature and resistivities of NbN films suggested that a majority of the NbN films formed by reactive dc sputtering at high pressure are characterized by a negative temperature coefficient of resistivity. A grain-boundary scattering model yields results which correspond to the experimental results more closely than the theoretical results derived from an electron localization model. This indicates that grain boundary scattering determines the pathway of transport in sputtered films while defect scattering and impurity scattering do not significantly influence the transport mechanism.

Cooperative manner of grain boundary sliding is exhibited in direct observations with a scanning electron microscope at different structural levels of superplastic shear deformation in the Lead-Tin eutectic alloy. Microscopic level study of the alloy shows that orientation and shape of shear surfaces varies with deformations. Shear surfaces at the beginning have lens-type shape, but when there is an increase in strain, the surfaces become S-shaped.

Anomalous superconducting critical currents which are associated with magnetic flux pinning are found in 14 degree(001) tilt grain boundaries of YBa2Cu3O(7 to delta). This indicates that no interfacial structure can be associated with the misorientation of YBa2Cu3O. The geometry of the grain boundary corresponds to the special interface within the coincidence of constrained lattices which explains the anomalous superconducting behavior of YBa2Cu3O grain boundaries. The tetragonal-to-orthorhombic phase transformation influences the grain boundary structure and properties. This provides new methods for production of high-current superconductors.

An experiment investigates the electromigration characteristics and kinetics of damage formation for Al(Cu,Si) line segments on a continuous W line and two-level interconnect in the Al(Cu)/W. The drift velocity technique is used in the measurement of the mass transport as a function of temperature. The kinetic process is not controlled by dissolution of the Al2Cu precipitates but by electromigration of Cu along the grain boundaries.

The thermoelastic characteristics of twist grain-boundary superlattices on the (100) plane in fccCu and Au were investigated. The results showed that the in-plane and out-of-plane thermal-expansion coefficients featured a strong anisotropy. A complicated interplay of the structural order arising from the interfaces determined the thermal expansion of the superlattices. Thermal expansion was associated with the elastic characteristics of the superlattices.

The effect of hot pressing on the superconducting, microstructural and grain boundary characteristics of high quality fine grained PbMo6S8 was investigated using scanning electron microscopy and ac-susceptibility measurements. The results showed that the hot pressing process induced densification and improved grain connection. However, inhomogeneities such as Pb and S deficiencies at the interface effectively limited the critical current density.

The grain-boundary and dislocation self-diffusion coefficients in silver were directly determined using an Ag radiotracer during experiments in type-C kinetics conditions. The results showed that an implanted, mass-separated carrier free Ag radiotracer enhanced the sensitivity for measuring grain-boundary penetration profiles. In contrast with conventional methods, the technique allowed penetration profiles to be distinguished.