Spectroscopic Ellipsometry (SE) was chosen to study thin film growth in atomic layer deposition (ALD). It was shown that Cauchy model had limitations in predicting the ultrathin film thickness at initial few deposition cycles, and the fitting results depend on wavelengths range greatly. Effective Medium Approximation (EMA) model is capable of predicting ultrathin film’s physical properties. Our experiments on Al2O3 growth give supporting evidence on the applicability of EMA model, where it is used to successfully explain the initial nucleation and island like growth. EMA model can be extended to be used for Palladium thin film, which can give reasonable thickness and void content.

Effects of adding Erbium(Er) to Aluminum Nitride thin films on their structural and piezoelectric are reported along with stability of the films after annealing them at temperatures up to 600° C. The thin films samples were deposited on the (001) p-type silicon substrates by reactive magnetron sputtering, using the Er alloyed Aluminum targets with Er atomic concentrations of 0, 1, 3 and 4% and the magnetron sputtering power of 200 W. The samples were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). XPS analysis was used to confirm the stoichiometry of AlN phase, Er atomic content and its possible chemical state in the films. Results show that alloying with Er results in higher piezoelectric coefficient d33 as compared to that in Er-free AlN thin films. Structural analysis of the films by XRD shows the shift of (0002) AlN peak to lower 2θ values upon Er doping, indicating the presence of uniform internal compressive stress.

Papers in the Appendix were published in electronic format as Volume 1534

Ternary nanocomposites of poly (lactic acid) (PLA) were produced by melt blending with two types of elastomers and five types of organoclays to obtain improved mechanical properties such as tensile strength, modulus and impact strength. One of the elastomers is a random copolymer of ethylene and glycidyl methacrylate (E-GMA) and the other one is a random terpolymer of ethylene-butyl acrylate-maleic anhydride (E-BA-MAH). Organically modified montmorillonites (OMMT) were utilized as nanofillers. XRD, DSC, tensile and impact tests were done on the injection molded samples. FTIR, SEM and TEM analyses are still in progress. As preliminary results, thermal analysis showed that the addition of compatibilizers and organoclays does not have a distinct effect on the thermal properties of the composites, and no evidence of nucleation activity of compatibilizers or organoclays was found. For all types of organoclays, the nanocomposites produced with E-GMA exhibited better mechanical properties in comparison to nanocomposites containing E-BA-MAH, especially for the impact strength.

Wehave investigatedthe thickness dependence of air exposure of copper phthalocyanine (CuPc) layerson molybdenum trioxide (MoO3) with ultraviolet photoemission spectroscopy (UPS). It was found that after the air exposure, the WF of MoOx dropped severely. Meanwhile, with ∼10 ÅCuPcthin films covered on the top, there is no big change of the MoOx WF before and after the air exposure.

To better understand the mechanisms of creation and rupture of conductive filaments in resistive switching devices such as Cu/TaOx/Pt, with Cu and Pt being the active and inert electrodes, respectively, a device with limited supply of active metal electrode has been manufactured and electrically characterized. The limited supply of active metal has been realized by depositing a thin (delta) Cu layer (δ-Cu), 6 nm and 12 nm thick, on TaOx, resulting in a Pt/δ-Cu/TaOx/Pt device structure. The limited active metal supply i) has a direct impact on the onresistance (Ron) of the Cu bridge, and leads, after several conventional set-reset cycles, to ii) pulsating behavior, when device turns on and off repeatedly, to iii) symmetric switching behavior with respect to applied voltage polarity, when the device can be set and reset both at positive and negative bias, and to iv) volatile switching behavior.

Applications that produce a large amount of heat, such as combustion engines, can benefit from high temperature thermoelectrics to reduce the amount of energy lost. Superlattice (SL) structures have shown reduced thermal conductivity at room temperature and below, suggesting applicability at high temperatures may be possible. This reduction could greatly increase the thermoelectric figure of merit. The Si/SiGe material system is studied here for high temperature application. Two growth temperatures of 300 C and 500 C are examined. Two superlattice periods were studied (8 nm and 20 nm) to determine the effects of lattice spacing on thermal conductivity. Laser Flash Analysis is applied to determine the thermal diffusivity, hence thermal conductivity, from 100 C to 500 C. Thermal diffusivity was found to be an order of magnitude lower than the constituent alloy at 100 C. Superlattice spacing and growth temperature showed little effect on the diffusivity within the error of this measurement.

A new three-dimensional cell shape index using the AFM height images of cells cultured on cell substrates was defined. The new cell shape index revealed quantitative cell spreading information of cells that is not included in the conventional cell shape index. The quantitative morphometry of rat cerebral cortical astrocytes cultured on four different kinds of cell substrates were investigated using the conventional and the new cell shape index, and the results were compared. The new cell shape index showed the quantitative astrocyte spreading and stellation behavior that agrees with the AFM height images of astrocytes.

The influence of higher processing temperatures on the formation reaction of Cu(In,Ga)(Se,S)2 thin films using a three step reactive annealing process and on the device performance has been investigated. High process temperatures generally lead to the formation of larger grains, decrease the amount of void formation and their distribution at the back Mo/Cu(In,Ga)(Se,S)2 interface, and lead to a much faster formation reaction that shortens the overall reaction process. However, high temperature processing also leads to a decrease in device performance. A loss in open circuit voltage and fill factor could be attributed to enhanced interface recombination processes for the samples fabricated at higher process temperatures, which itself may be caused by a lack of Na and subsequent poor passivation of interface defect states. The lack of Na resulted in a decrease in free charge carrier concentration by two orders of magnitude.

Papers in the Appendix were published in electronic format as Volume 1534

In this study the PANI/PHBV blends were prepared and thermal properties, crystallization behavior, microstructure of the blends were investigated. The PANI/PHBV blends were prepared by dissolution of PANI (emeraldine base doped with dodecylbenzenesulphonic acid, DBSA) and PHBV in chloroform and films were obtained by casting. PANI amount in the blend was varied from 0.1 to 1% wt. PANI/PHBV blends were characterized by FTIR spectroscopy and the thermal behavior were analyzed by differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). FTIR spectra of the pure PHBV and PANI/PHBV blend had similar peaks. However, blends spectra show an enlargement of bands, due interaction of the chain PANI with PHBV matrix. The crystallization behaviors were investigated using DSC, with at a scanning rate of 10oCmin−1. Curve of pure PHBV showed two melting peaks (159.1°C and 172.3°C). With the increase of PANI amount in the PHBV matrix, both of the melting peaks became wider and shifted to lower temperatures. The decrease trend of first and second melting points with increase of PANI amount, suggests a reduction in the crystallinity of the blends.

Studies of carrier motion in a variety of nanostructures have indicated that a modified Drude model can be applied, by considering carrier bound motion from backscattering mechanisms and localized oscillator modes. Based on the results of these studies a model of damped harmonic oscillation modes is suggested to evaluate transport parameters in piezotronic devices. Here, the case of a system subject to static and low frequency piezoelectric fields is considered which corresponds to typical working conditions of nanogenerators and, as a working example, the response of ZnO nanowires excited by sound waves is analyzed.

Graphene composites (GCs) have attracted much attention recently. It is interesting to explore thermal properties of GCs in which graphene filler concentrations are tunable. Here, we use 3ω method to measure the thermal conductivity of GCs synthesized from reduced graphene oxide (RGO) dispersed in polystyrene. To avoid the detrimental effect of lithography processes to GCs, we have developed a novel method employing polyvinyl alcohol and poly(methyl methacrylate) (PMMA) as a holder film to transfer micrometer-sized metal heaters/sensors onto GC surface. Room temperature measurements of the thermal conductivity of GCs are performed. The thermal conductivity is enhanced by ∼ 35 % when adding 5 vol.% of RGO filler concentration. Our measurements will be helpful to probe and understand the thermal transport properties of graphene based composites.

We have analyzed the hopping movement of a new ionic solid electrolyte by calculating defect formation energies and activation barriers. The role of the lattice during diffusion was established. Thermodynamic properties were determined by means of first principles and phonon calculations at working temperatures. The new solid electrolyte, an antiperovskite, Li3-2xMxAO (in which M is a higher valent cation like Ca2+ or Mg2+ and A is a halide like Cl- or Br- or a mixture of halides), was studied either pure or doped. Moreover, we present experimental ionic conductivity data for these novel solid state ionic conductors for the doped and the pure solid electrolyte from room temperature and up to ∼253 °C. In this paper, we compare the ionic conductivity of the latter solid electrolyte with other fast ionic conductors.

In this paper, we present a work plan for the dissemination of refreshable, photoactuatable tactile displays to the visually impaired, serving both Lab-to-Market and Lab-to-Classroom initiatives. The work plan is designed in accordance with the logic model, which identifies an overlap amongst classroom, market, and laboratory. This overlap seems to nucleate when a technology in developmental phase is deployed in a classroom with high affinity to such technology. In this scheme, students are stakeholders whom help decide both content and applications to be included in the developing curriculum, and provide technology feedback, effectively leading to increased consumer acceptance. The identified Lab-to-Market-to-Classroom continuum could be the missing link where to nurture sustainable scientific, technological, and curricular development.

The evaluation of the redox conditions in the Swedish ILW-LLW repository, SFR-1, is of high relevance in the performance assessment. The SFR-1 repository contains heterogeneous types of wastes, of different activity levels and with different materials in the waste and in the matrices and packaging. Steel and concrete-based materials are ubiquitous in the repository. The assessment presented in this work is based on the evaluation of the redox conditions and of the reducing capacity in 15 individual and representative waste package types in SFR-1. A combination of the individual models is used to determine the redox evolution of the different vaults in the repository. The results of the model indicate that in the initial time after repository closure, O2 is consumed through degradation of organic matter and metal corrosion during the initial time after repository closure. Afterwards, the system is kept under reducing conditions for long time periods, and H2(g) is generated due to the anoxic corrosion of steel forming magnetite as main corrosion product. The time at which steel is depleted varies with the amount and characteristics of steel and ranges from 5,000 to over 60,000 years. After complete steel corrosion, the reducing capacity of the system is mainly given by magnetite. The calculated redox potential under the chemical conditions imposed by the massive amounts of cements in the repository is in the order of -0.75 V (at pH 12.5). In case of assuming that the Eh of the system is controlled by the interaction between Fe(III)/Magnetite as a result of groundwater/magnetite interactions, redox potentials in the range -0.7 to -0.01V are calculated, considering the uncertainty in the pH prevalent in the system If the absence of oxic disturbances the Eh of the repository system would be kept reducing. In the event of oxidising and diluted glacial meltwater intrusion, magnetite would gradually convert into Fe(III) oxides, buffering the redox potential of the system and preventing it from oxidation for long time periods.

In this work we report on opportunities for a colossal reduction in lattice thermal conductivity (LTC) of graded micro-nanoporous structures with inhomogeneous porosity which leads to the considerable improvement in thermoelectric figure of merit ZT. We employ the effective medium theory to calculate the LTC of a porous media with hole pores of variable radius and show that porous materials with inhomogeneous porosity are expected to have stronger reduction (about 30 times!) in thermal conductivity than those with pores of equal sizes. Such a reduction is caused by enhanced scattering of thermal phonons with the pore boundaries. We have studied the variations of the LTC as a function of porosity, pore sizes, geometry and the number of pore groups with different sizes. Our theoretical results show excellent agreement with experimental data.

This paper describes an alternate two-step metallization scheme for porous dielectrics. The patterned dielectric surface is first treated in a plasma etch chamber where the dielectric surface is coated with a very thin carbon-based film. This is followed by electroless copper deposition. The plasma post-etch treatment (PET) film seals the pores of the dielectric, minimizes dielectric damage, and functionalizes the dielectric to enable electroless plating.

We use data over an extended Q range from 0.01 to 100Å-1 from the recently commissioned NIMROD instrument at the ISIS pulsed neutron source to develop a multi-scale inverse modeling procedure which will provide insight in to the phase transformations of polymer systems. The first level of our procedure is atomistic and we use internal coordinates (bond length, bond angles and torsion angles) to define the polymer chain in full atomistic detail. Values were assigned to each internal coordinate within the chain using a stochastic Monte Carlo method in which the probabilities were drawn from distributions representing the possible range of values. Using this approach, random chain configurations could be rapidly built and the intrachain structure factor calculated utilizing a small set of parameters and compared with the experimental function. Parameters representing the probability distribution functions were systematically varied using a grid search to find the values which gave the best fit to the structure factor for Q > 3Å-1 in order to determine the details of the chain conformation in the molten phase. This process was repeated for data over the same extended Q range obtained at lower temperatures where the polymer was expected to crystallize. Polymers crystallize via chainfolded thin lamellae crystals. Such crystals give rise to an intense peak at Q ∼ 0.03Å-1. This scattering can be calculated using a lamellar stack model, coarse-grained from the single chain structure. We describe this approach using data obtained on the crystallization from the melt phase of perdeuterated polymers. The objective here is to follow the three key length scales; the chain folded lamellar thickness of ∼ 10nm, the crystal unit cell ∼ 1nm and the detail of the chain conformation is ∼ 0.1nm.

We have proposed new magnetic memories using parallel-aligned nanowires without mechanical moving parts, in order to achieve the ultra high transfer rate of more than 144 Gbps for Super Hi-Vision TV. In the magnetic memory using nanowires, the data are stored as the magnetic domains with up or down magnetization in magnetic nanowires, and the domains are shifted quite faster by applying optimum current along the nanowire direction for data writing and reading purpose. Since the electric circuits and the insulation space between the neighbor nanowires are necessary for moving the magnetic domain walls, the areal recording density is essentially reduced as compared with that of conventional hard disk drives. In this study, in order to increase the areal recording density of magnetic nanowire memory, we have tried to act one magnetic nanowire as the virtual multiple data tracks. The shallow scratched trench was introduced using scanning probe microscopy along the length direction on the surface of a single nanowire to form multiple internal tracks, and we have succeeded in realizing a couple of virtual tracks states.