Several diverse types of UH3-based hydrides can be prepared by hydrogenation of bcc U-based alloys. Pair Distribution Function (PDF) analysis using high-energy X-rays identified that the (UH3)1-x Mox hydrides are nanocrystalline, with the structure motif based mainly on the β-UH3 structure. α-UH3 represents a minority component. On the other hand, PDF of the (UH3)1-x Zrx hydrides corresponds well to the α-UH3 crystal structure. All the hydrides are ferromagnetic, with the Curie temperature T C reaching up to 203 K.

Fabrication methods and performance characteristics of spiral stretchable interconnects fabricated using drop-on-demand printing of silver reactive inks are discussed. This work details ink optimization, device fabrication, and device characterization while demonstrating the potential applications for reactive inks and new design strategies in stretchable electronics. Devices were printed with an ethanol stabilized silver diamine reactive ink and cycled to 160 % over 100 cycles with less than 10% increase in electrical resistance. Maximum deformation before failure was measured at 180% elongation. A novel method for fabrication of a stretchable electronics device has been studied and verified.

For exploring the prospect of higher-k dielectric phase engineering on a highmobility substrate, films of Hf1-xZrxO2 withvarying x-values (0 ≤ x ≤ 1) were deposited onAl2O3 passivated Ge substrates using atomic layerdeposition (ALD) with a cyclic deposit-anneal-deposit-anneal (DADA) scheme. Theevolution of monoclinic to higher-k tetragonal structure with increasingZrO2 concentration was probed by grazing incident x-raydiffraction and partial reciprocal space maps using the highly brilliantsynchrotron x-ray source at the Cornell High Energy Synchrotron Source (CHESS).A primarily amorphous/nano-crystalline matrix of the asdeposited films changedto randomly aligned grains of nanocrystalline MO2 (M=Hf, Zr)after post deposition annealing at 800 °C for 200 seconds. In contrast,the DADA films annealed for same thermal budget showed high degree of preferredorientation along certain crystallographic directions. With increasingZrO2 content, the structure of the films changed from a monoclinic toa tetragonal phase. A lower amount of ZrO2 (x = 0.33) wasrequired for stabilizing the tetragonal phase in films grown onAl2O3 passivated Ge substrate as compared to similarfilms grown on a Si substrate via the same DADA process (x ≥0.50).

Accurately predicting fission gas releases (FGR) from high burn-up fuels during off-normal conditions, such as a loss-of-coolant accident (LOCA), is an important, major challenge. A significant step forward would be to identify and assess the basic mechanisms causing this FGR. A helpful way of better understanding these basic mechanisms is to separate these effects and to perform irradiations on materials simulating the nuclear fuel. Mesoporous or dense CeO2 and UO2 samples (with thin film geometry) were selected for these studies as materials representative of irradiated fuels. A basic mechanism to obtain a better understanding of FGR is described and a new methodology using thin film samples is developed to test the validity of this mechanism.

We recently demonstrated a sub-bandgap photoresponse with our wafer-scale Au/TiO2 metallic-semiconductor photonic crystals (MSPhC). The sub-bandgap energy with 590 nm peak could be absorbed in the form of hot electron and injected to TiO2, which provides 5.28 times more energy for photolysis than that of energy absorbed to flat TiO2. If the solar energy already absorbed above 700 nm could be injected to the catalyst, higher than 10 times improvement will be achieved, and above 20% solar to fuel efficiency will be feasible with the robust but inefficient TiO2 catalyst. In order to achieve photocurrent near and above 700 nm spectrum, we deposited gold nanorods on the surface of MSPhC to incur localized surface plasmon (LSP) modes absorption and subsequent injection to the TiO2 catalyst. We used electrophoretic deposition (EPD) method to deposit nanorods on the top, sidewall and bottom well surface of the photonic nanocavities. The deposition of nanorods was achieved reasonably uniform and sparse not to block the optical cavities of MSPhC. Flat gold surfaces were tested at 4 different suspension densities to get the optimum gold nanorods density. Under 10V applied electric field, positively charged gold nanorods at the concentration of 6.52×1013 #/mL could deposit MSPhC surface with the density of 230 #/µm2, which was reasonably uniform and sparse. Preliminary tests show an absorbance increase near 700 nm on flat device coated with gold nanorods. Photocurrent measurement is under way to demonstrate the enhanced hot electron transfer over full visible light and near-infrared solar spectrum.

We report preparation and characterization of colloidal gold nanorods (AuNR) with plasmon absorbance over 950 nm and an aspect ratio of 7.2 by tuning silver nitrate concentration and the CTAB/BDAC ratio during growth. Samples were analyzed by scanning transmission electron microscopy, X-ray diffraction, UV-vis absorption spectroscopy and measurement of zeta potential. Addition of 170 μM silver nitrate to the CTAB-containing reaction mixture allowed preparation of AuNRs with a maximum absorbance peak at 941.8 nm and a yield around 96%. Optimization of the BDAC/CTAB ratio allowed for a further redshift of the absorbance maximum to 954.0 nm, but with poorer yields.

In this paper the defects generated by ion implantation in 4H-SiC DIMOSFET (Double Implanted MOSFETs), and their evolution after annealing process, have been studied in detail. The point defects generated by the source or body implantation process have been detected by micro-photoluminescence (µPL) and the effect of these defects on the electrical characteristics of the DIMOSFET has been studied. The role of the annealing process has been carefully investigated by using different temperatures. It appears fundamental for the restoring of the crystal damage. The effect of the ion implantation dose has been investigated as well. By reducing the source ion implanted dose a large decrease of point defects has been detected and a considerable improvement of the electrical characteristic of the DIMOSFET has been observed.

A method for creating pH maps in microchannels containing liquid/liquid and liquid/gas phases comprised of water and CO2 is demonstrated. It is based on a glass slide coated with nanoparticles exhibiting metal-enhanced fluorescence. The time resolution is better than 500 ms, limited by the fluidic control. This work opens the way for new in situ measurements of physical dissolution and chemical reactions in dynamic CO2 gas-liquid systems.

Recent developments in a number of fields call for high-throughput, high-resolution imaging of large areas. Examples are reconstruction of macroscopic volumes of mouse brain tissue, or wafer defect inspection. To address these needs, we have developed a multi-beam, single column SEM which utilizes an array of 61 or 91 electron beams and detectors in parallel. The total possible detection speed of the multiple beam SEM is the single detection speed times the number of beams. In the same time a single beam SEM creates an image of several million pixels size, the multi-beam SEM produces between several hundred million and one billion pixels. Herein we demonstrate the capabilities of generating massive data sets using the multi-beam SEM on a variety of samples including brain tissue serial sections and semiconductor test wafers.

We report fully-printed top-gate-bottom-contact organic thin-film transistorsusing substrates prepared from cellulose nanofibers and commercially availableprinting inks to fabricate the devices. Gravure printing was used to coat thesubstrate with a polymer resist to decrease the surface roughness and close thesurface. Transistor structures were fabricated using inkjet printing forconductors and gravure printing for the dielectric and semiconducting layers.The obtained transistor performance is compared to that of similar transistorson plastic substrate.

3C-SiC devices are hampered by a high crystal defect density due to the hetero-epitaxial growth of these films, which results in the presence of stacking faults (SF). In this paper high growth rate CVD processes have been used to try to reduce the SF density in 3C-SiC films. In a first step a high growth rate (30 μm/h) has been used to grow 50 μm thick 3C-SiC layer on (100) Si. Then the silicon substrate was removed via etching and a further 3C-SiC growth was performed with a higher growth rate (90 μm/h) at a higher temperature (1600 °C) to obtain a final thickness of 150 μm. The SF presence and density were evaluated by TEM analysis performed on as-grown samples and SEM analysis on KOH etched samples with various thicknesses. A decrease of SF density was observed with an increase of 3C-SiC film thickness, with the best results (500/cm) obtained for the thickest sample. The 3C-SiC film quality and orientation was evaluated by XRD are correlated with film thickness and SF density.

The behavior of nanostructures under high strain-rate conditions has been object of interest in recent years. For instance, recent experimental investigations showed that at high velocity impacts carbon nanotubes can unzip resulting into graphene nanoribbons. Carbon nanoscrolls (CNS) are among the structures whose high impact behavior has not yet been investigated. CNS are graphene membranes rolled up into papyrus-like structures. Their unique open-ended topology leads to properties not found in close-ended structures, such as nanotubes. Here we report a fully atomistic reactive molecular dynamics study on the behavior of CNS colliding at high velocities against solid targets. Our results show that the velocity and scroll axis orientation are key parameters to determine the resulting formed nanostructures after impact. The relative orientation of the scroll open ends and the substrate is also very important. We observed that for appropriate velocities and orientations, the nanoscrolls can experience large structural deformations and large-scale fractures. We have also observed unscrolling (scrolls going back to planar or quasi-planar graphene membranes), unzip resulting into nanoribbons, and significant reconstructions from breaking and/or formation of new chemical bonds. Another interesting result was that if the CNS impact the substrate with their open ends, for certain velocities, fused scroll walls were observed.

High purity UO2 powder samples were subjected to accelerated aging under controlled conditions with relative humidity ranging from 34% to 98%. Characterization of the chemical speciation of the products was accomplished using X-ray photoelectron spectroscopy (XPS). A shift to higher uranium oxidation states was found to be directly correlated to increased relative humidity exposure. Additionally, the relative abundance of O2-, OH-, and H2O was found to vary with exposure time. Thus, it is expected that uranium oxide materials exposed to high relative humidity conditions during processing and storage would display a similar increase in average uranium valence.

In Japan, scallop shells are considered to be industrial waste. Thus far, attempts for reusing these shells have been mainly limited to the commercial production of CaCO3. Nevertheless, there are no clear economic benefits associated with the use of scallop shells as a source of CaCO3. Hence, we are attempting to investigate a new value-added use for scallop shells as an advanced functional material. In this regard, we focused our attention on nuclear wastewater, which contains radioactive Sr and Cs. Sr, which tends to accumulate in bones, is believed to cause bone cancer. Hence, it is highly desirable to develop a method for removing Sr from contaminated water. In this study, we investigate whether scallop shells demonstrate the ability to remove Sr from a solution. From the results obtained, scallop shells can remove Sr solutes from a solution; furthermore, as compared to CaCO3, they demonstrate superior ability for removing Sr.

Organic solar (OPV) cells are cheap electronics that can replace the widely used high cost silicon-based electronics for electricity generation. They are cheap because of the easy techniques involved in their fabrication processes and they can be produced to cover a large surface area. However, the current low performance of organic electronics has been traced to failure due to interfacial adhesion problems, material processes, and service conditions. Therefore, transportation of charge carriers across the bulk heterojunction system of OPV cells becomes very difficult in the presence of these flaws. In this paper a combined experimental and computational technique is used to study the reliability and physics failure of stretchable OPV cells. Interfacial adhesion energies in the layered structures of OPV cells are measured and compared with theoretical estimated energies. The limit stresses/strains applied on layered OPV cells during service condition are estimated using critical values of the measured interfacial adhesion. The results obtained are, therefore, explained to improve the design of reliable OPV cells.

We report on a hand-held reactive printing device used to pattern highlyconductive, edible hydrogel wires formed from gellan gum, gelatin, cross-linkersand a common salt (NaCl). The conductivity of the gels when printed (190± 20 mS/cm) closely matched the conductivity recorded for cast systems(200 ± 19 mS/cm). Printing was observed to reduce the elastic modulusand failure strains of hydrogels under compression, but printed gels retainedsufficient integrity for application as flexible conductive lines. Wedemonstrate that hand-held printing can utilize to pattern soft conductorelements within a simple electronic circuit.

We report observation of narrow nanowires and high density nanodots on the Si(001) surfaces when they are exposed to a single application of interferential irradiation of laser pulses of 7 ns. These nanostructures form selectively depending on interference parameters so that their placements can be controlled by controlling the parameters. The morphologies of the nanostructures are studied by atomic force microscopy. The nanowire width increases with interference period. The narrowest nanowires observed have the width smaller than 26 nm, which is eight times smaller than the interference period while the nanodots have a very large density of 1.8 ± 0.45) × 1011/cm2.

The thermal conductivity, bulk modulus, thermal expansion and heat capacity forbulk β-Ga2O3 are calculated from latticedynamics using both a quasi-harmonic approximation and an anharmonicforce-constant approach involving a solution of the linearized Boltzmanntransport equation. The role of anharmonicity inβ-Ga2O3 is determined to be small, whichleads to the weak volume dependence of the calculated thermal conductivity. Thenegligible anharmonic contribution to the overall thermal conductivity isconsistent with both thermal expansion measurements and also with comparisonsbetween the quasi-harmonic and anharmonic methods. Phonon-mode-dependentGrüneisen parameters are found to be weakly dependent on temperature.Negative values of the mode Grüneisen parameters are found for certainlow energy optical modes, but their net effect on the overall thermal expansionis insignificant. Bulk modulus as well as heat capacity are also given and foundto be in agreement with experimental results.

This paper reports on a monolithic 10 cm × 10 cm area PV module integrating an array of 72 a-Si:H n-i-p cells on a 100 μm thick polyethylene-naphtalate substrate. The n-i-p stack is deposited using a PECVD system at 150 °C substrate temperature. The design optimization and device performance analysis are performed using a two-dimensional distributed circuit model of the photovoltaic cell. The circuit simulator SPICE is used to calculate current and potential distributions in a network of sub-cell circuits, and also to map Joule losses in the front TCO electrode and the metal grid. Experimental results show that the shunt leakage is one of the factors reducing the device performance. Current-voltage characteristics of individual a-Si:H p-i-n cells were analyzed to estimate a variation of shunt resistances. Using the LBIC technique, the presence of multiple shunts in the n-i-p cell was detected. To understand the nature of electrical shunts, the change in the surface roughness of all device layers was analyzed throughout fabrication process. It is found that surface defects in plastic foils, which are thermally induced during the device fabrication, form microscopic pinholes filled with highly conductive top electrode material.

Graphite-doped hematite and magnetite nanoparticles systems (∼50 nm)were prepared by mechanochemical activation for milling times ranging from 2 to12 hours. Their structural and magnetic properties were studied by57Fe Mössbauer spectroscopy. The spectra corresponding tothe hematite milled samples were analyzed by considering two sextets,corresponding to the incorporation of carbon atoms into the iron oxidestructure. For ball milling time of 12 hours a quadrupole split doublet has beenadded, representing the contribution of ultrafine particles. TheMössbauer spectra of graphite-doped magnetite were resolved consideringa sextet and a magnetic hyperfine field distribution, corresponding to thetetrahedral and octahedral sublattices of magnetite, respectively. A quadrupolesplit doublet was incorporated in the fitting of the 12-hour milled sample. Therecoilless fraction for all samples was determined using our previouslydeveloped dual absorber method. It was found that the recoilless fraction of thegraphite-doped hematite nanoparticles decreases as function of ball millingtime. The f factor of graphite-containing magnetitenanoparticles for the tetrahedral sites stays constant, while that of theoctahedral sublattice decreases as function of ball milling time. These findingsreinforce the idea that carbon atoms exhibit preference for the octahedral sitesof magnetite.