Mechanical properties and thermal stability of bulk glassy alloys depend on their chemical composition ratios, although their detailed local structures especially around free volume have not been clarified yet. In order to know the origin of property dependence on alloy composition in Zr-Cu-Al ternary bulk glassy alloys in a view point of atomic scale, positron annihilation lifetime, coincidence Doppler broadening (CDB) and EXAFS (extended X-ray absorption fine structure) measurements have been employed for eutectic Zr50Cu40Al10 and hypoeutectic Zr60Cu30Al10 bulk glassy alloys before and after structural relaxation by annealing below glass transition temperature Tg .

The result of CDB experiment, which represents the electron momentum distribution around free volume, shows that significant atomic reordering around free volume does not take place by the annealing in each alloy. Besides, CDB ratio profiles for each alloy suggest that the fraction of Zr atom around free volume does not match the chemical composition of each alloy system. Change in positron lifetime, which is proportional to the size of free volume, during annealing for hypoeutectic alloy almost remains unchanged.

The effect of fine M2C particles on the recrystallization temperature and high temperature strength of warm rolled Fe3Al base alloys was investigated. Fe-27Al-1.2C-2Cr-xMo (x: 0.3, 0.9) alloys (in at.%) were arc melted, warm rolled and annealed. TEM observations have revealed that fine M2C particles were present in the alloy containing 0.9% Mo but not in the alloy with 0.3% Mo after warm rolling. The recrystallization temperature increased from 740 °C to 810 °C when the Mo content is increased from 0.3 to 0.9 due to the presence of fine M2C particles. Tensile tests conducted on annealed samples with fine sub-grained matrix have shown that the introduction of fine M2C particles is effective to enhance the proof stress at 600 °C.

We report on a combined structural and electronic analysis of niobium ultrathin films (from 2.5 to 10 nm) epitaxially grown in ultra-high vacuum on atomically flat sapphire wafers. We demonstrate a structural transition in the early stages of Nb growth, which coincides with the onset of a superconducting-metallic transition (SMT). The SMT takes place on a very narrow thickness range (1 ML). The thinnest superconducting sample (3 nm/ 9ML) has an offset critical temperature above 4.2K and allows to be processed by standard nanofabrication techniques to generate air and time stable superconducting nanostructures.

Amorphous Ta-N thin films (14 and 62 nm thick) are deposited on Si substrates by reactive magnetron sputtering followed by Cu film deposition. The interlayer reaction and failure mechanism of the annealed metallization stacks are investigated by resistance measurements, xray diffraction (XRD) and detailed electron microscopy analysis accompanied with electron energy-loss spectroscopy (EELS). Amorphous Ta-N crystallizes at 600°C by a polymorphous transformation to Ta2N. The crystallized Ta2N barrier prevents Cu-Si interaction and intermixing up to 700-800°C, depending on the barrier thickness. Copper appears to be the main diffusing species and reacts with Si at the Ta-N/Si interface to form η˝-Cu3Si. Local Cu-Si reaction enhances the formation of TaSi2 precipitates. Silicon also diffuses, though at a much slower rate, to the surface and reacts with Cu. Local oxidation of Cu3Si occurs upon exposure to air, accompanied by SiO2 formation.

The structure of irradiated material near a primary knock on atom shortly after impact is largely unknown. Molecular dynamics simulations with classical force fields provide the foundation for our current understanding of the resulting cascade. Atomic level structural characterization is often in terms defects within the context of a perfect bulk, however, the choice of the best representation is complicated because the density of defects is high, the material is inhomogeneous and it is not in equilibrium. Here we explore the adaptation of tools typically employed to characterize homogeneous equilibrium liquids to the highly defected region of the cascade. The cascade structure shows some resemblance to that of the liquid or glass phase. The local temperature temporarily exceeds the melting temperature and the free energies of the liquid and defected crystal are comparable. Analysis of cascade structure will be important to the interpretation of first principles calculations of the electronic and magnetic states in cascade structures.

Resonant cavity light emitting diode (RCLED) structure was grown using digital AlGaN/GaN Distributed Bragg Reflector (DBR) and Ag-based p-contact. A five period of InGaN/GaN multi-quantum well (MQW) layers are placed between these two high reflectance mirrors. Digital AlGaN/GaN DBR have a maximum reflectivity of about 60 % at 445 nm and 90 % at 439 nm for 6 period and 12 period, respectively. Ag-based p-contact exhibits an average reflectance of around 85-90 % for a wavelength of 400-600 nm. The light output intensity of the RCLEDs with 12 period digital AlGaN/GaN DBR is higher by a factor of 3 as compared to that of the similar structure without digital AlGaN/GaN DBR at an injection current of 50 mA.

There is widespread interest in developing efficient solar cells derived from conjugated polymers and TiO2. The conjugated polymer can act as a light harvesting dye as well as a hole transport material, and can potentially replace both the ruthenium dye and the I3 -/I- couple in the DSSCs. Herein, we report a novel and facile approach of using conjugated polymer nanoparticles to make conjugated polymer:TiO2 nanocomposite based solar cell. Nanoparticles from poly(3-hexylthiophene) (P3HT) were made using mini-emulsion technique. In this work we report on incorporation of these P3HT nanoparticles into nanoporous titania. Device characteristics made using P3HT nanoparticle sensitized solar cells were measured. These devices showed a short-circuit current density (Jsc) of 0.207 mA/cm2, open-circuit voltage (Voc) of 0.62 V and 0.07% (η) efficiency.

Recently, we have proposed a spin quantum cross structure (SQCS) device toward the realization of novel spintronics devices. In this paper, we have investigated thermoelectric effects in point contacts (PCs) of Ni ferromagnetic metals using SQCS devices, theoretically and experimentally. The calculated results show that the thermoelectric voltage Vq changes from 0.48 mV to 2.12 mV with the temperature difference of PCs increasing from 10 K to 50 K. Also, the magnitude of the theoretical thermoelectric voltage agrees very well with that of the experimental result. PCs of SQCS devices with Ni electrodes can serve as spin dependent thermobatteries.

Oxide-embedded Silicon nanoparticles (OE-Si-NPs) are of great interest for many applications due to unique size effects observed when their size drops below 5 nm (Silicon’s Bohr exciton radius). Some of the suggested applications require patterning of the nanoparticles in an ordered array. Lithographic methods to pattern Si-NPs are common in the literature, however these methods can be costly, and are not time-efficient. Recently, non-lithographic patterning techniques have become very attractive because they are cost-effective and straightforward. In this proceeding we will demonstrate non-lithographic patterning of OE-Si-NPs characterized via AFM and XPS.

We here present, metal nanocrystal (NC) formation statistics (size, density, occupancy or area coverage) on different high dielectric constant (high-K) materials which may be used as tunnel dielectric or intermetal dielectric in flash memory devices. Four important high-K materials viz. SiO2, Al2O3, HfO2 and Si3N4 are chosen for this purpose and the nanocrystal formation statistics has been found to be strongly dependent on dielectric. Among all the four dielectrics, smallest size nanocrystals with largest density are obtained on Al2O3 dielectric while on HfO2 bigger size nanocrystals are formed. This difference in nanocrystal size and density on different dielectrics is attributed to the different surface properties of these materials.

The stability of elongated single- and multi-layered graphene nanoribbons (GNRs) are investigated by molecular-dynamics simulation. In order that GNRs are to be modeled as nanobridges connecting two terminals of electronic devices, the short edges of the GNRs are constrained. The distances between the two constrained edges are gradually increased, and the GNRs are uniaxially strained. The energies and out-of-plane deformations of such uniaxially strained GNRs are examined. The energies of multi-layered GNRs will be lower than those of isolated GNRs because the surface areas of multi-layered GNRs are smaller than the total area of the isolated GNRs. Understanding the relationship between the out-of-plane deformations and strain will lead to the control of the ripple structures of GNRs.

Interface state density profiling of the thermal oxide / n-type 4H-SiC interface which underwent post-oxidation nitric-oxide (NO) annealing showed that an interface state density of approximately 1×1011 cm−2eV−1 could be achieved at around 0.2 eV below the conduction band. It decreased exponentially by two orders to 1×109 cm-2eV-1 at around 0.9 eV from the conduction band. The values are comparable or better than other published work. The low interface state density achieved near the conduction band is important towards improved channel carrier mobility in SiC MOSFETs. A positive flat-band voltage shift of the SiC based MOS capacitor was also observed. The shift reduced under UV illumination. It could be attributed to slow acceptor-like (negatively-charged) traps, which may have contributed to the instabilities observed in drain current and threshold voltage suffered by SiC MOSFETs.

Stable, catalytically active, and inexpensive halogen electrodes are essential for the success of the regenerative hydrogen-halogen fuel cell as a competitive means of large-scale electricity storage. We report the synthesis and electrochemical testing of two novel electrode materials — ruthenium-cobalt and ruthenium-manganese alloy oxides. These alloys were fabricated by wet chemical synthesis methods as a coating on a titanium metal substrate and tested for chloride and bromide oxidation and for chlorine and bromine reduction. These alloy oxides exhibit high catalytic potency and good electrical conductivity good stability, while having a significantly reduced precious metal composition compared to commercial chloride oxidation electrodes made of the oxide of a ruthenium-titanium alloy. We tested alloys with Ru content as low as 1% that maintained good electrochemical activity. Stability tests indicate immeasurably small mass loss.

High-temperature measurements of the spatial distribution of the displacement characteristics of a thickness shear mode langasite (La3Ga5SiO14) resonator are obtained using a laser Doppler interferometer. Thereby, the resonator is excited in the fundamental mode and the third overtone. Further, the resonator is coated with a gas sensitive CeO2-x film which exceeds the metal electrode. In reducing atmospheres the conductivity of the film increases and induces an increase of the effective electrode area. This effect leads to a broadening of the mechanical displacement distribution. The latter depends strongly on the size of the excited part of the resonator which is determined by the effective size of the electrodes. The direct determination of the mechanical displacement at different oxygen partial pressures confirms a model as derived from the electrical impedance of resonator devices [1]. Further, information about the mass sensitivity distribution of resonators is obtained since the property is directly proportional to the amplitude.

Silicon nanowire solar cells were simulated using the Silvaco TCAD software kit. For optimization of speed the simulations were performed in cylinder coordinates with cylindrical symmetry. Symmetric doping was assumed with a dopant density of 1018 cm-3 in the p-type core and inside the n-type shell. In the implementation a cathode contact was wrapped around the semiconductor nanorod and an anode was assumed at the bottom of the rod. Optimization of cell efficiency was performed with regard to the rod radius and the rod length. In both optimization processes clear maxima in efficiency were visible, resulting in an optimal radius of 66 nm with the pn junction at 43.5 nm and an optimal rod length of about 48 μm. The maximum of efficiency with respect to the rod radius is due to a decrease of short-circuit current density (Jsc) and an increase of open-circuit voltage (Uoc) with radius, while the maximum with respect to the rod length is explained by the combination of an increase of Jsc and a decrease of Uoc. Fill factors stay rather constant at values between 0.6 and 0.8. Further, the influence of a back surface field (BSF) layer was surveyed in simulations. Positioning the BSF next to the cathode contact considerably improved cell efficiency. In addition, simulations with a cathode contact on top of the nanowire structure were undertaken. No severe deterioration of cell performance with increasing radius was observed so far in this configuration. Hence, nanorods with much larger radii can be used for solar cells using this contact scheme. In comparison to simulations with wrapped cathode contacts, Jsc and Uoc and therefore efficiency is considerably improved.

Nanoimprint lithography is a low cost method which produces trillions of nanostructures on a substrate. One application of this technology is patterned magnetic media where a single imprint on a disk can create a masking layer with more than a trillion nanostructures. Several challenges exist to imprinting bit patterned media (BPM) at a density greater than 1Tbit/in2. This technology would allow an extension of hard drive magnetic recording at densities greater than 1Tbit/in2. One such challenge is imprint resist mechanical properties where the imprinted masking layer should be free of thickness variations and resist flop-over. Herein we describe the nanoindentation mechanical properties of several imprint resist systems along with analysis of imprinted features of BPM at densities between 200-482 Gdots/in2.

We report electrochemical characteristics of hydrogen terminated charge-transfer doped intrinsic microcrystalline diamond films. Microcrystalline diamond was synthesized by Direct- Current Plasma Enhanced Chemical Vapor Deposition (DC-PECVD) in methane diluted by hydrogen. The diamond films were subjected to further treatment by microwave plasma in pure hydrogen to increase the hydrogen termination of the diamond surfaces and their negative electron affinity. When the diamond is exposed to the ambient moisture, valance electrons tend to tunnel from the first few atomic layers of the diamond surface to the adsorbed water adlayer. This charge transfer process results in the surface of hydrogen-terminated diamond behaving like a p-type semiconductor.

Electrochemical characteristics of hydrogen-terminated diamond films were exposed to an air plasma for depleting the surface hydrogen atoms and then re-hydrogenated the same diamond films with atomic hydrogen. Cyclic voltammetry in 0.1M H2S04 aqueous solution and 0.01M Fe(CN)6 -4/-3+0.1M KCl aqueous solution was applied to reveal high current density and wide potential window for hydrogen-terminated diamond grown on silicon substrates. The faceted surface morphology has been observed by SEM. The crystalline characteristics and carbon phases in the diamond film were examined by Raman spectroscopy.

The industrial dyeing apparatus excavated in Pompeii have been preserved and remain in situ. To understand Pompeii’s economy, and its place in the Roman world, it is necessary to first understand the capabilities of a single industry. Before this study, the size of the dyeing industry was calculated by applying theory to a superficial measurement of the remains. This study was the first to realise that to understand an industry it was necessary to reconstruct and use the relevant parts.

The most comprehensive survey of the apparatus was undertaken. A full-scale physical replica was constructed from materials that physically and thermally matched the originals. This study was the first to define the dyeing cycle time, temperatures reached and fuel type and quantity required. Finite Element Analysis (FEA) was used to model a virtual replica to show the effect of external influences on the materials during use. The lead metal data did not exist before this study. This was the first use of FEA to model an archaeological apparatus or artefact of more than one material. The dyeing industry had been far smaller than originally thought.

Archaeological virtual replications tend to be aesthetic. This study produced a rare physical replication. When this is combined with data from the original survey and physical replicas each apparatus is now ‘preserved by record’ and may be recreated. Some of the apparatus in Pompeii have been amended in an attempt to reconstruct and preserve them. This study has shown that the amendments are incorrect and potentially misleading.

Prior to this study the size of the industry was a controversial ‘unanswerable’ question. This study provided a solid foundation that answered the question and illustrated a new approach, through a method that provided a means of preserving the apparatus for the future.

Monoclonal antibodies are increasingly used in the treatment of cancer due to their enhanced targeting and immune system stimulation properties. Dosage guidelines typically do not account for personal cancer load or metabolism, thereby possibly affecting treatment outcome or causing unwanted side effects. The requirement for an assay that can quickly and precisely measure the concentration of the monoclonal antibody in a serum sample of a patient during therapy is unmet. A bead-based assay with peptide antigen mimetics has been developed to rapidly determine the concentration of antibody drug present in serum specimens with high sensitivity. Alemtuzumab (anti-CD52) and rituximab (anti-CD20) antigen mimetic peptides, as discovered by phage display, were synthesized on 10 um TentaGel resin beads using conventional solid phase peptide synthesis techniques. The beads were modified to allow for multiplexing and microfluidic handling via fluorescent labeling and magnetic functionalization. The antigen-displaying fluoromagnetic particles were incubated with spiked serum samples which allowed free antibody to be captured. Primary antibody detection was performed on alemtuzumab while rituximab detection was used to compensate for non-specific serum binding to the beads. After washing, the beads were incubated with a fluorescently tagged secondary label for detection by flow cytometry. (Results) A fast, low cost, specific assay has been developed with several key techniques which allows detection at low concentration (0.1ug/ml) of spiked samples. Primary to achieving this detection limit was the implementation of a compensation scheme where two antigen mimetic peptides behave linearly (R2=0.996) which enables the calculation of the zero response of the antigen mimetic peptide of interest (alemtuzumab antigen mimetic) while measuring the zero response of the compensatory antigen mimetic peptide (rituximab antigen mimetic) during primary assay measurement. This reduces fluorescence response variation due to variations present due to sample preparation, storage and different patients because of the equivalent interactions these effects have on the compensatory beads. The developed assay is therefore robust against serum variation and enables a lower limit of detection.