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Shock-induced elastic-plastic deformation in pure aluminum is examined at 4 GPa peak stress by measuring wave profiles in thin samples under plate impact loading. The combination of large elastic wave attenuation in thin samples and differences in sample thicknesses has shown a consistent picture of shock propagation in pure aluminum where time-dependent elastic-plastic response is confined to material very near the impact surface.

The generality of hole-current-related degradation is understood by examining the behavior of 9,10-diarylanthracenes (DAAs), which is the important class of blue-fluorescing light-emitting-layer hosts. The effects of unipolar currents in tris(8-quinolinolate)aluminum (Alq) and 2-t-butyl-9,10-di(2-naphthyl)anthracene (TBADN) are studied.

Molecular dynamics simulation is used for examining the interface and surface structure of transition metal (TM) (Fe, Co, Ni) thin film deposited on Al(001) substrate at atomic level. The different structural and intermixing characteristics at the interface are described in terms of lattice matching, cohesive energy and local acceleration effect.

The structure and dielectric characteristics of Ba[[([Fe.sub.0.9][Al.sub.0.1]).sub.0.5][Ta.sub.0.5]][O.sub.3] solid solution are examined. The studies have shown that the low-temperature dielectric relaxation has originated from the mixed-valent structure of [Fe.sup.2+]/[Fe.sup.3+], which has played a role in the hopping of the charge carriers between them and the improvement in the dielectric characteristics in the Al-substituted Ba[([Fe.sub.0.5][Ta.sub.0.5])[O.sub.3] ceramics.

([Ba.sub.0.6][Sr.sub.0.4])Ti[O.sub.3] (BST) thins films are deposited on (100) and (110) oriented LaAl[O.sub.3] (LAO) single-crystal substrates by radio-frequency magnetron sputtering system. The current-voltage (I-V) measurement has shown that the leakage current density of BST films grown on LAO (110) is reduced when compared to that of BST films grown on LAO (100).

77.3 K Self-oscillations is described in a 30-period weakly coupled GaAs/[Al.sub.0.3][Ga.sub.0.7]As superlattice (SL). The analysis of frequency spectra of self-oscillations under external sinusoidal force in frequency-locked regime at different fixed voltages has showed that current oscillations detected in the structureless regions of the I-V characteristic of weakly coupled SLs are forced oscillations.

The thermal expansion coefficients of the hexagonal SiC polytypes 4H and 6H and the Al and N dopants are determined. A set of the room temperature lattice parameters in dependence on doping with N, Al, and B is obtained.

A high-performance millimeter wave absorber composed of a series of aluminum-substituted [epsilon]-iron oxide nanomagnets are prepared. The aluminum-substituted [epsilon]-iron oxide is very economical and hence these materials are very useful for industrial applications.

Photoelectron spectroscopy was employed to identify Al-related interfacial dipole in the Hf[O.sub.2][Al.sub.2][O.sub.3]/Si[O.sub.2] gate stack. The dipole located at the Al-silicate interface between [Al.sub.2][O.sub.3] and Si[O.sub.2] could find potential applications in metal-oxide-semiconductor devices.

A study was conducted to explore the capacitance characteristics related to voltage and frequency of n(+)-GaN/[Al.sub.x][Ga.sub.1-x]N heterojunction ultraviolet (UV)-infrared (IR) photodetectors. The Al fraction in the barrier layer was observed to significantly change the positions of the interface trap states relative to the Fermi level.

The low-temperature absorption spectra between 1700 and 350 nm and the low-temperature vacuum ultraviolet absorption spectra between 400 and 190 nm for [Er.sup.3+]:YAl[O.sub.3] (YAP) are reported. The crystal-field wave functions for the ground-state manifold of [Er.sup.3+]([4f.sup.11]) are used to calculate the orientation-dependent anisotropic magnetic susceptibility as a function of temperature over the Curie-Weiss region.

Off-axis holography is used for measuring the electrostatic potential profile across AlGaAs/AlAs/GaAs heterostructures containing n or p-doped AlGaAs layers. The electrostatic potential has dropped at the epilayer/substrate interface and the corresponding sheet concentrations of charge due to interfacial impurities are determined.

The kinetics of oxides growth in the GaAs surface are analyzed by using in situ x-ray reflectometry (XRR) method on a GaAs/AlAs multilayer system showing the possibility to model reaction process at the surface by means of XRR. Total reflection x-ray fluorescence analysis of twin samples has confirmed that the oxidation process is promoted by x-ray exposure and has shown the presence of a richer As oxide phase at the surface of the x-ray irradiated samples.

The effect of the surface treatment of Al nanoparticles on the electrical properties of linear low density polyethylene composites is examined. The improved electrical properties are attributed to the good dispersion and special electrical feature of the surface-treated nanoparticles in the polymer matrix.

The magnetotransport properties of 100 nm wide parabolic quantum wells are studied and an enhancement of the Hall resistance is observed in one sample but not the other. The interaction correction to the Drude conductivity is extracted, where the extracted interaction correction has increased with increasing tilted angle.

The analysis has shown the efficient energy transfer from Si nanoparticles (NPs) to [Er.sup.3+] ions in a nonsilica-based material [Al.sub.2][O.sub.3]. The results have shown that a higher percentage of [Er.sup.3+] ions are sensitized by Si NPs and have stressed the importance of controlling the dopant distribution at the nanoscale to achieve improved device performance.

The fabrication and analysis of organic light-emitting devices (OLEDs) with a cohosted emitter of various component ratios is described. The parameters exploring the energy transfer process, the spectra overlap integrals and Forster's radius is calculated for understanding the dependence of luminance efficiency of the resulted OLEDs on the measured composition ratio.

The different metallization schemes, namely, Ag, Al, In, and Sn to SnS films are examined to understand the crucial task of selection of Ohmic contacts for the fabrication of efficient SnS devices. All M/SnS structures, except Ag/SnS, showed excellent Ohmic behavior over the voltage range from -10 to 10 V at room temperature and their thermal stabilities are examined by annealing them at different temperatures.

A study is conducted to examine the structural evolution and microscopic and bulk magnetic properties of Fe/Al multilayer thin films with an overall atomic concentration ratio of Fe:Al = 1:2 prepared by ion-beam sputtering. The as-deposited multilayer structure (MLS) is influenced by the Fe and [Fe.sub.3]Al-like region formed at the interface.

The development of an analytic solution to space charge limited currents with exponentially distributed traps is reported. The newly developed analytic solution is able to predict a voltage dependent slope and much higher current magnitudes compared to conventional solution due to critical contribution of background carriers.

Monochromatic and white beam synchrotron x rays are used to study the deviatoric strains and full elastic strains in passivated Al conductor lines with near-bamboo structures during electromigration (EM). The experimental and numerical calculations using Eshelby model and finite element method (FEM) method indicated that the EM is observed mainly along the top and bottom interfaces, with less EM flux near the edges of the line than near the center.

The full Penn algorithm (FPA) is adopted to derive the energy loss function for the calculation of differential inelastic mean free paths (IMFPs). The results of the energy distributions and the secondary electron emission yields for Al and Cu have agreed well with the experimental results.

Two different bipolar resistive switching behaviors of Ti[O.sub.2] film in metal-insulator-metal (MIM) structures (Al/Ti[O.sub.2]/Pt/substrate and Pt/Ti[O.sub.2]/Al/substrate) are described. The nature of the resistive switching phenomena in various binary oxide materials is explained by a combination of the bulk effect and the interface effect that occur between the metal electrode and oxide materials.

Conducting atomic force microscopy and scanning surface potentials microscopy are used for studying the nanoscale surface electrical properties of aluminum zinc oxide (AZO) films that are prepared by pulsed laser deposition (PLD) at various substrate temperatures for use as anode materials in polymer light-emitting diodes (PLEDs). The low-temperature condition for PLD has reduced the yield rate of impurities when AZO vacuum evaporation is performed on a plastic substrate, thus supporting various applications of AZO films.

Multiscale simulations are performed to examine the nucleation of dislocations in a single-crystal Al sample and analyze the role of unavoidable indenter roughness. The studies have shown the underlying dislocation nucleation mechanism for atomically rough indenters is dependent on temperature, with surface nucleation favored at lower temperatures.

The possibility of bandgap engineering in binary systems of oxide insulators is explored by studying the photoconductivity of nanometer-thin Hf oxide layers containing different concentrations of cations of different sorts (Si, Al, Sr, or Ce) deposited on (100)Si. Photoconductivity is shown as a feasible method to trace phase separation in nanometer-thin layers of binary systems of metal oxides.

Low temperature photoluminescence spectroscopy is used for analyzing the effects of the postgrowth thermal annealing on the electronic structure ad carrier dynamics of GaAs/AlGaAs quantum dot and quantum ring structures grown by droplet epitaxy. The modifications of the photoluminescence band depending on the thermal annealing temperature are interpreted by using a simple model based on the Al-Ga interdiffusion.

X-ray diffraction method is used for structural characterization of the monocrystalline phase and the orientation of the Yb doped [Lu.sub.3][Al.sub.5][O.sub.12] single crystal fibers grown with various [Yb.sup.3+] ion concentrations. The results revealed that the micro-pulling down technique is capable of producing single cyrstalline materials with uniform distributions of active dopants and optical quality comparable to that of bulk crystals created by conventional melt growth techniques.

The specific characteristics of the dielectric properties of a MnZn ferrite/Al based composite in which conducting filler (Al) with high-resistance oxide overlay ([Al.sub.2][O.sub.3]) enables to effect on charge transport and thus control the [epsilon] in the material are reported. The analysis of the efficiency of hybrid composites (HCs) with different types of conducting filler as electromagnetic wave absorbers (EWAs) indicated that the matching frequency of EWAs is controlled in the radio-frequency range through an appropriate choice of the type of conducting filler.

Temperature-dependent photoluminescence (PL) spectroscopy is used to study the effects of exposure to ambient air on the optical property of Al-doped ZnO nanorods. The results showed that the room temperature optical properties of Al-doped ZnO nanorods is not influenced by exposure to oxygen-rich atmosphere but might degrade the electrical properties due to reduction of the Al donors.

A wet chemical and an electrochemical route is used to obtain [Al.sup.3+]-doped ZnO nanocrystals. The feasibility of incorporation of [Al.sup.3+] in ZnO nanocrystals might find potential use in obtaining ferromagnetic ordering in ZnO nanocrystals and in other applications where thin conducting nanocrystalline films are required.

Charge injection properties of the other alkali-metal fluorides at the tris-(8-hydroxy-quinolinato) aluminum ([Alq.sub.3])/electron injection layer/Al cathode interface of organic light emitting diodes are analyzed. The studies have shown that the device performance is equivalent for the alkali-metal fluorides despite the major difference in electronegativities.

The sputter ripple formation in polycrystalline metal thin films of Al, Co, Cu and Ag is studied by 16.7 keV [Ar.sup.+] and [O.sub.2.sup.+] ion bombardment as a function of angle of ion incidence. The lower values of lateral straggling widths as those extracted from the measured critical angles using the Bradley and Harper theory has shown a highly anisotropic deposited-energy distribution.

The Mg[Al.sub.2][O.sub.4] (MA) microwave dielectric material is added to prepare barium strontium titanate (BST) composite and to analyze the relation between the internal vibrational modes and the microwave dielectric properties of the BST composite. Raman analysis has shown that the incorporation of MA lowers deterioration on B-site ordering of AB[O.sub.3] perovskite structure.

The effect of a magnetic field on the photocurrent in an aluminum tris(8-hydroxyquinolate) based organic light emitting diode is measured and the contribution to the organic magnetoresistance of both electrons and holes is identified. The changes are due to the magnetic field dependence of the scattering of electrons and holes with excited states within the device.

The reactive magnetron sputtering of ScN and YN onto [alpha]-[Al.sub.2][O.sub.3] single crystal substrates is described that has resulted in a single-orientation epitaxy. The mobility power laws described for ScN and YN has shown that these materials might display very high mobility at low carrier concentration.

First principles calculations are used for studying the impact of Al incorporation on the effective work function of a TiN/Hf[O.sub.2] interface. The studies have shown that the shift of the work function has increased with increasing the Al concentration at the interface.

The electrical and thermal properties of quaternary icosahedral [Al.sub.71-x][Ga.sub.x][Pd.sub.20][Mn.sub.9] (x = 0, 2, 3, 4) quasicrystals are measured in accordance with the guiding principle of weakly bonded rigid heavy clusters (WBRHCs). The studies have shown that the control of the thermoelectric properties in these materials is the main obstacle for them from being a good thermoelectric material.

The degradation behaviors of Al-doped ZnO (AZO) films epitaxially grown by pulsed laser deposition (PLD) as well as the underlying physics of thermal annealing effects on the reversible change in electrical properties are examined. A photoluminescence study has indicated that oxygen interstitial is a critical parameter that has allowed for the reversible control of the electrical conducting properties of AZO films.

Raman and infrared (IR) spectroscopies are applied for the examination of optical phonons in relaxed [In.sub.x][Al.sub.1-x]As alloys grown by molecular-beam epitaxy on GaAs. Analytical expressions are obtained for the frequency variation with In composition for the optical phonon modes and also the variations in their intensity and linewidth.

The strained-tetrahedron model is used for interpreting published extended x-ray absorption fine structure data on the wurtzite structure of epitaxial GaAlN thin films grown on a sapphire substrate. The studies have shown that beyond a concentration of 50 percent of Al, these thin films have grown less homogeneously regardless of the method of preparation.

Pure ZnO and aluminum doped ZnO films (ZAO) are prepared by sol-gel method and the effect of Al doping on the microstructure and electrical properties of the films is examined. The results have shown that the transformation from granular to columnar structure is observed in pure ZnO films with the increase in heating time while in aluminum doped films little structural changes have occurred even after a prolonged heating time.

The gas electron diffraction (GED) method along with quantum chemical calculations were used to determine the molecular structures of chloro(phthalocyaninato)aluminum(III) (ClPcAl) and chloro(phthalocyaninato)-gallium(III) (ClPcGa). The results from calculations showed all the molecules to have [C.sub.4v] symmetry with the metal atom above the plane defined by the four inner cavity N atoms and an almost planar macrocycle.

Near-lattice-matched GaN/AlInN multiple quantum wells (MQWs) are examined by using the diamond anvil cell high-pressure method. The studies have shown that despite of minimizing piezoelectric component in such a structure, there is still large built-in electric field originated from the spontaneous polarization characteristic for nitrides crystallizing in wurtzite structures.

The synthesis of [Ce.sup.3+]-doped yttrium aluminum garnet nanophosphors with sizes near 30 and 250 nm is reported. The results from the size-dependent electron-longitudinal-optical-phonon coupling show that the coupling strength decreased from the bulk material to the nanophosphors of much smaller sizes.

The studies of AlGaAs/InGaAs/GaAs metal-oxide-semiconductor-pseudomorphic high electron mobility transistors (MOS-PHEMTs) with [Al.sub.2][O.sub.3] as a gate dielectric oxide prepared in low-temperature liquid phase deposition (LPD) are presented. The studies have demonstrated the use of LPD [Al.sub.2][O.sub.3] as a suitable candidate for future gate insulator applications.

A study is conducted to compare the electrical and structural properties of AlN/GaN heterostructures grown by molecular beam epitaxy on sapphire with those of AlGaN/GaN heterostructures. The composite buffer of the structure could be made semi-insulating by proper choice of the Fe doping in GaN(Fe) and the thickness of unintentionally doped GaN layers.

The Mg[F.sub.2]/Al omnidirectional reflectors (ODRs) are used to enhance the light extraction of GaN-based light emitting diodes (LEDs.). The results showed that the ODRs consisting of Mg[F.sub.2] and Al yield the angle-integrated reflectivity of 96.6%, which enhanced the output of LEDs by a factor of 1.23.

The photophysical properties of axial-bonding types (terpyridoxy)aluminum(III) prophyrin (Al(PTP)), bis(terpyridoxy)tin(IV) porphyrin (Sn[(PTP).sub.2]) and bis(terpyridoxy)phosphorus(V) porphyrin ([[P[(PTP).sub.2]].sup.+]) are analyzed. The results have clarified the role of the internal molecular structure and the reduction potential for electron transfer from the terpyridine ligand to the excited porphyrin.