Wood and paper are ubiquitous in societies around the world and are largely taken for granted as part of traditional industries with no new science to learn. Many of the technologies used in the forest products industry have been gained empirically through experience. The complexities of wood are now yielding to newer tools and we are beginning to see how the mechanical, optical and other physical properties of wood are related to hierarchical structures based on 2 to 10 nm diameter several hundred nm long fibers of nanocrystalline cellulose (NCC). The liberation of these NCC’s is allowing their re-assembly into remarkably strong structures. Examples will be given of the nature of these building blocks and structures assembled from them. Examples will include nanocomposites as well as very high strength “paper”. Paper is another example of a process whereby nanofibrils are released and then re-assembled with the use of “retention, drainage and formation aides” to make substrates we call paper with remarkable strength to weight performance. Other disciplines call this process “self-assembly” and the “aids” as necessary surfactants and additives to control structure and performance. Glossy magazine papers, for example, have approximately 10 micron thick coatings of white minerals and latex binders which are increasingly of nano dimensions. The coatings are assembled in structures to provide optical barrier performance (opacity) as well as controlled ink interaction with the necessary strength to survive printing and handling. These coatings are frequently similar in structure to seashells and, from this knowledge, progress has been made in understanding the mechanisms at play in achieving higher strength coatings. More recently kaolin clays have been introduced with mean crystal thicknesses in the range 20 to 40 nm instead of the usual 100 to 140 nm. These clays show useful strength performance and represent what may be called pragmatic nanoclays. Novel chemistries based on biomimetic learnings are emerging to displace the conventional starch or latex binders. Examples will be given of protocols for moving toward higher strength systems.

Solid state sintering of Ag nanoparticles was used to bond Cu wires to Cu foils at temperatures less than 250°C. The Ag nanoparticles are coated with an organic shell to prevent sintering at room temperature. After annealing the nanoparticles at 200°C, the decomposition of the organic shell was confirmed using TGA and Raman spectroscopy. The joint strength was measured by tensile shear tests, which shows that the joint strength increases as the bonding temperature increases. Metallic bond between Ag nanoparticles and Cu was achieved with no contamination. Bonds formed by our method, was confirmed to withstand temperatures higher than the bonding temperatures.

CdSe/ZnS nanocrystals are embedded in para-sexiphenyl (p-6P) based hybrid light emitting diode devices providing red, green and blue (RGB) emission compatible to the HDTV color triangle. By structural and optical investigations the device parameters are optimized. The device performance is analyzed in respect to electrical and spectral response resulting in current-voltage characteristics with small leakage currents and low onset voltages. Furthermore the devices provide high color purity and stability which is demonstrated by their narrow emission line widths. All these results underline the ability of the presented device configuration to act as a future candidate for display applications.

The properties of a carbon nanotube (CNT), in particular a single-wall carbon nanotube (SWNT), are highly sensitive to the atomic structure of the nanotube described by its chirality (chiral indices). We have grown isolated SWNTs on a silicon substrate using chemical vapor deposition (CVD) and patterned sub-micron probes using electron beam lithography. The SWNT was exposed by etching the underlying substrate for transmission electron microscope (TEM) imaging and diffraction studies. For each individual SWNT, its electrical resistance was measured by the four-probe method at room temperature and the chiral indices of the same SWNT were determined by nano-beam electron diffraction. The contact resistances were reduced by annealing to typically 3-5 kΩ. We have measured the I-V curve and determined the chiral indices of each nanotube individually from four SWNTs selected randomly – two are metallic and two are semiconducting. We will present the electrical resistances in correlation with the carbon nanotube diameter as well as the band gap calculated from the determined chiral indices for the semiconducting carbon nanotubes. These experimental results are also discussed in connection with theoretical estimations.

Immobilization of long-lived 99Tc requires development of chemically resistant inorganic matrices. Samples of ceramics based on crystalline Fe-Mn- and Zr-Mn-oxide compounds were synthesized at 1150°C in air, reducing or inert atmosphere from precursors doped with 5-12 wt.% Tc. All the samples obtained were studied using optical and scanning electron microscopy (SEM); powder X-ray diffraction (XRD) and microprobe analysis (EMPA). Content of Tc varied from 0.5-0.8 to 3-6 wt.% in oxide host phases and from 54 to 93 wt.% in metallic inclusions. It was demonstrated that synthesis of oxide host-phases under oxidizing or reducing conditions was not optimal due to partial Tc volatilization or metallic phase formation, respectively. The use of inert atmosphere for ceramic synthesis supports Tc incorporation into crystalline structure of stable host-phases. Development of optimal methods of precursor preparation and synthesis conditions of Tc-doped ceramic are being discussed.

Nowadays, Si3N4 coatings are used to increase the hardness of 316L-type stainless steel for a wide variety of applications. These coatings are normally prepared by chemical vapor deposition (CVD) or variant techniques such as the hybrid solid-gas precursor system chemical vapor deposition (HYSYCVD), where Na2SiF6 is used as a solid precursor. Within the reaction chamber the Si-F gas species interact with nitrogen precursors to form Si3N4; however, during silicon nitride formation there is always certain amount of residual Si-F gas species which may affect the integrity of the steel surface. Therefore, in this work the effect of the Si-F species on the surface of 316L type stainless steel under argon atmosphere has been investigated. Stainless steel samples were prepared under two surface conditions (abraded and mirror polished), and were exposed to Si-F species considering various parameters such as: argon gas flow rate equal to 10 cm3/min, different temperatures (300, 500, 700, 900°C), and three exposure times (30, 60, 90 minutes). After exposure, the substrates were characterized by X-ray diffraction (XRD) and by scanning electron microscopy (SEM). The results show that the FeF2 phase is formed at low temperatures while the formation of different oxides is directly related to the processing temperature. What is more, these oxides are also strongly influenced by processing time; however temperature is the parameter that most significantly influences the oxides formation.

Traditional techniques to remove contaminants (carbon adsorption, incineration, biological activity and chemical treatment) have a lot of disadvantages. Advanced Oxidation Processes (AOP’s) are used as alternative processes in the degradation of surfactants and in general for wastewater treatment. They are based on the generation of OH•, one of the most powerful oxidant known (E° = 2.73 V) and capable to react non-selectively with any organic compound. In the present work, the degradation of a cationic surfactant (dodecylpyridinium chloride (DPC)) was performed. The photodegradation reaction was investigated both in a slurry reactor and in a vessel where the photocatalyst (P25 by Degussa) was anchored onto an aluminum surface to avoid the final filtration of the powder at the end of the reaction. Moreover a new photoreactor was built on purpose to investigate the influence of the pressure on the degradation process.

The thermo-optical properties of gold nanoparticles suspended in liquid water droplets have been explored. A water droplet containing suspended gold nanoparticles was irradiated with a laser beam and the efficiency of light-to-heat conversion (η) was determined. Heat generated by the optically stimulated nanoparticles was found to dissipate through several mechanisms. Convection currents were observed visually inside the droplet by the addition of silica beads (˜3-10 micrometers). This was determined to be the dominant mechanism of stirring within the droplet.

The interface and electrical properties of HfAlO dielectric formed by atomic layer deposition (ALD) on sulfur-passivated GaAs were investigated. X-ray photoelectron spectroscopy (XPS) revealed the absence of arsenic oxides at the HfAlO/GaAs interface after dielectric growth and post-deposition annealing at 500 °C. A minimal increase in the amount of gallium oxides at the interface was detected between the as-deposited and annealed conditions highlighting the effectiveness of HfAlO in suppressing gallium oxide formation. An equivalent oxide thickness (EOT) of ∼ 2 nm has been achieved with a gate leakage current density of less than 10-4 A/cm2. These results testify a good dielectric interface with minimal interfacial oxides and open up potential for further investigation of HfAlO/GaAs gate stack properties to determine its viability for n-channel MOSFETs.

The availability of large, single crystals of cadmium zinc telluride (CZT) with uniform properties would lead to improved performance of gamma radiation detectors fabricated from them. However, even though CZT crystals are the central element of these systems, there remains relatively little fundamental understanding about how these crystals grow and, especially, how crystal growth conditions affect the properties of grown crystals. This paper discusses the many challenges of growing better CZT crystals and how modeling may favorably impact these challenges. Our thesis is that crystal growth modeling is a powerful tool to complement experiments and characterization. It provides an important approach to close the loop between materials discovery, device research, systems performance, and producibility. Specifically, we discuss our efforts to model gradient freeze furnaces used to grow large CZT crystals at Pacific Northwest National Laboratories and Washington State University. Model results are compared with experimental measurements, and the insight gained from modeling is discussed.

An alternative bottom-up Cu electro-less deposition (ELD) method without other catalyst material activation tested on blanket wafers, is the focus of this paper. The process consists in reducing the Cu ions via standard reducing agents, such as dimethylamine borane (DMAB). A wide range of experimental conditions such as pH, temperature, Cu ion concentration and time are investigated and the Cu layer nucleation and growth mechanism is evaluated on clean SiO2 and after functionalization with 3-aminopropyltrimethoxysilane (APTS) self-assembled monolayer (SAM) used as copper diffusion barrier. The barrier properties of the APTS layer after Cu ELD are also assessed by copper resistivity measurements and visual inspections as a function of the annealing temperature.

We have developed new gene expression-regulating polymer that can activate transgene expression in response to target intracellular signals. Here, we tried applying sonoporation system to this gene regulation system to enhance the gene expression efficacy. Sonoporation is the method for effective gene transfection in vitro and in vivo. Therefore, the method might enhance the transfection efficiency in our polymer and realize an efficient and safe gene delivery system. Results suggested that the combination of our polymer and sonoporation could improve the gene expression compared to the system using only our polymer that transfers genes into cells via endocytosis. It also kept the ability of the gene regulation responding to cellular signals.

The reaction kinetics of [(Ti-Te)]x[(Sb-Te)]y, [(Bi-Te)]x[(Sb-Te)]y, [(Ti-Te)]w[(Bi-Te)]x and [(Ti-Te)]w[(Bi-Te)]x[(Ti-Te)]y[(Sb-Te)]z precursors as a function of annealing temperature and time was probed using x-ray diffraction techniques to define the parameters required to form superlattice structures. [(TiTe2)1.36]x[Sb2Te3]y and [(TiTe2)1.36]x[Bi2Te3]y superlattices were observed to form while [(Bi-Te)]x[(Sb-Te)]y precursors yielded only Bi2-xSbxTe3 alloys. This behavior was correlated with the immiscibility/miscibility of the constituents of the targeted superlattices. For the three component system, Bi and Sb were observed to interdiffuse through the Ti-Te layer over the range of Ti-Te thicknesses explored, resulting in formation of (BixSb1-x)2Te3 alloys within the superlattice structure. When the Bi2Te3 and Sb2Te3 thicknesses were equal, symmetric [{(TiTe2)}1.36]w[(Bi0.5Sb0.5)2Te3]y superlattices were formed.

The introduction of high-speed services for fiber-optic access subscribers has led to a huge growth in data traffic. The rapid diversification of services means that next generation networks must be built quickly, economically and reliably.

A high temperature laser allows us to eliminate the thermo-electric cooler conventionally needed in a transmitter module, which results in reductions in cost, power consumption and size. Moreover, a high-power laser provides a wide tolerance when coupling optical fibers. In addition, a high-power pump laser is needed to realize a wide-band and high-power erbium-doped fiber amplifier. This makes high-performance laser chips one of the keys to achieving highly reliable and cost-effective systems.

In terms of laser reliability, we must clarify the degradation mechanism and postpone or suppress degradation if we are to achieve a reliable high-performance laser. We have analyzed degraded lasers using the optical beam induced current (OBIC) technique. When there are nonradiative recombination centers in the degraded region, the OBIC intensity decreases with increases in recombination density. This technique has the advantages of being non-destructive and highly sensitive. In addition, it provides high space resolution in degradation analyses.

The OBIC is measured through the window of a transistor outline (TO) can before and after aging. Then, by using the same LDs we can detect an OBIC change for several aging times. We can both detect the degraded region and layer, and estimate the degree of laser degradation by employing the relative OBIC intensity prior to aging. This OBIC technique is useful for analyzing the degree of laser degradation.

Moreover, the incident wavelength can be changed by changing the optical source in the OBIC measurement setup, which in turn changes the absorption layer and the penetration distance. Some degraded laser layers are reveled by using these several wavelengths absorbed in different layers. In addition, degradation in the waveguide interior is detected by using an incident wavelength with long penetration. Thus, by monitoring the OBIC intensity at several wavelengths as well as before and after aging, we are able to discuss sudden and wear-out laser failures. In our presentation, we will introduce examples using the OBIC technique that contributed to the improvement of laser reliability.

We demonstrate the feasibility of a new approach of Nano Selective Area Growth (Nano-SAG) to precisely localize InAs/InP QDs, by low-pressure Metalorganic Vapour Phase Epitaxy (MOVPE). This approach is based on a partial patterning with a dielectric mask containing nano-openings. The two main advantages of MOVPE are: the important diffusion length of the active species and the inhibition of growth on the dielectric mask. We demonstrate the synthesis of localized nanostructures with high structural properties and the precise control of their dimensions at the nanometer scale. This allows in principle the precise control of the tunability of the emission length.

Manipulation of bio-fluids in microchannels faces many challenges in the development of lab-on-a-chip devices. We propose magnetically actuated artificial cilia which can propel fluids in microchannels. These cilia are magnetic films which can be actuated by an external magnetic field, leading to an asymmetric motion like that of natural cilia. The coupling between different physical mechanisms (magnetostatics, solid mechanics and fluid dynamics) is numerically established. In this work we quantify the flow through a microfluidic channel as a function of its geometry for a characteristic set of dimensionless parameters.

We have developed on the DIFFABS-SOLEIL beamline a biaxial tensile machine with synchrotron standard for in-situ diffraction characterization of thin polycrystalline metallic film mechanical response. The machine has been designed to test cruciform substrates coated by the studied film under controlled applied strain field. Technological challenges comprise the fixation of the substrate, the generation of a uniform strain field in the studied (central) volume, the operations from the beamline pilot. Tests on W and W/Cu multilayers films deposited on polyimide substrates are presented.

Reduction of parasitic capacitances and improvement of the on-off current ratio (ION/IOFF) can be achieved by increasing the gate control in Field Effect Transistors (FETs). Multiple gated FETs (MugFETs) lend themselves well for this. The MugFET investigated in this manuscript is the Screen Grid FET (SGrFET) that consists of multiple gate cylinders inside the channel perpendicular to the current flow. In this work we illustrate, using 2D Technology Computer Aided Design (TCAD), that the multiple geometrical degrees of freedom of the SGrFET can be exploited to simultaneously optimise the on-current, ION and the gate-drain Miller parasitic capacitance for increased switching speed.

The microcavity effect of two-dimensional W surface-relief gratings has been investigated by means of the finite-difference time-domain simulation. The peak structure of the spectral emissivity of W gratings with a number of microcavities is in good agreement with the spectral features of a single microcavity. This result shows that the emissivity enhancement by W gratings with microcavities is mainly attributable to the microcavity effect that arises from each microcavity. It is that the spectral emissivity can be controlled by a combination of several microcavities with different parameters, and that not only a rectangular but a cylindrical microcavity also shows the microcavity effect according to its cavity modes.

Effects of very high frequency- plasma enhanced chemical vapor deposition (VHF-PECVD) using diluted ultrapure silane at higher dilution ratio (R>30) on microstructures and optical characteristics of hydrogenated nanocrystalline silicon (nc-Si:H) film were studied. Nanocrystalline silicon films were prepared by at RF power ranging from 50 to 300 W. It was found that the transition from amorphous phase to nanocrystalline phase occurred between 100 W and 150 W. The nucleation mechanism toward nc-Si:H near the transition point of amorphous phase was discussed based on transmission electron microscopy with atomic scale. Further, it is suggested from UV-visible spectroscopy that nc-Si:H films with the best optical properties would be obtained near the transition point from the amorphous phase to the crystalline phase.