Silver neodecanoate is sensitive to both ultra violet light (UV) and heat, and is a good inkjet printing precursor when dissolved in xylene. We have studied the electrical properties of inkjet printed silver samples, derived from silver neodecanoate ink, and investigated the influence of UV treatment before thermal curing the silver samples. In addition we have studied the influence of thermal pre-treatment on the printed samples. Thermally cured printed tracks and pads show minimum resistivity of approximately 3 x bulk silver. Their microstructure shows that the silver salt has converted to an interconnected network of silver nanoparticles after curing. The resistance of the printed tracks are shown to relate to the connectivity of the resulting sintered nanoparticle network as measured by the ratio of the sintered neck diameter to the original particle diameter.

The electrical characteristics of high quality single crystal boron-doped diamond are studied. Samples are synthesized in a high power-density microwave plasma-assisted chemical vapor deposition (CVD) reactor at pressures of 130-160 Torr. The boron-doped diamond films are grown using diborane in the feedgas at concentrations of 1 to 50 ppm. The boron acceptor concentration is investigated using infrared absorption and a four point probe is used to study the conductivity. The temperature dependent conductivity is analyzed to determine the boron dopant activation energy.

TiN provides a good template layer for the epitaxial SrTiO3 (001) growth on Si(001) single crystal substrates by RF sputtering. However, TiN template layer was oxidized into TiO2 during the subsequent sputtering process of electrodes of SrRuO3. The effect of Ru ion catalyzed oxidation and delamination of the TiN layer has been studied using transmission electron microscopy (TEM) and high-resolution transmission electron microscope (HRTEM). The epitaxial orientation relationship of the SrRuO3 and SrTiO3 was reserved to be cube on cube with respect to Si and the crystal quality of the SrRuO3/SrTiO3 film remained even when the TiN template layer was oxidized. The stress in the thin film of SrRuO3/SrTiO3/TiN structure could be determined from the buckle shape in both plan view and cross sectional TEM images.

Liquid resin hybridized silica sol-gels and thiol-ene elastomers were evaluated as compatible materials to form thin film, flexible multilayered structures. Liquid resins are cast and cured in air and ambient pressure on the order of minutes. Scanning Electron Microscopy (SEM) reveals homogeneous interfaces and robust interfacial adhesion under tensile and compressive stress. Thickness of the hybrid glass and thiol-ene films range from 0.80μm to 1.5μm and 8 μm to 16 μm respectively.

Crystal structure change with the temperature was investigated for 3 m-thick (100)/(001)-oriented epitaxial PbTiO3 films grown on SrTiO3 substrates. Complex strain-relaxed domain structure labeled as Type III was observed and directly transformed to the cubic phase at about 490°C. This transition temperature and the lattice parameter (a and c- axes) change with the temperature well agreed with the reported data for the PbTiO3 powders. The volume fraction of the (001) orientations, Vc, was almost independent of the temperature up to the phase transition temperature. The tilting angles of the spots in XRD plan view were almost the same with the estimated ones from the lattice parameters and the Vc. This suggests that the angle of the domains identified by the domain structure in Type III. This structure is mainly determined by the tetragonality, (c/a ratio) and the Vc.

Synthesis of Pb(Zr1–xTix)O3 (PZT) on a single substrate using a high-throughput molecular-beam epitaxy technique was demonstrated. In situ synthesis of crystalline PZT at elevated substrate temperatures could not be achieved, as reevaporation of Pb (PbO) occurred and the partial pressure of O2 was insufficient to prevent formation of a PbPtx phase during deposition. Instead, ex situ postdeposition annealing was performed on PZT deposited at room temperature. Dense single phase PZT was prepared with a compositional range of 0.1 > x > 0.9, for film thicknesses up to 800 nm. Transmission electron microscopy revealed the grain size increased from 50 nm to ∼0.5 μm with increasing Zr-concentration and became more columnar. Raman, x-ray diffraction, and scanning electron microscopy/energy dispersive spectroscopy results revealed a morphotropic phase boundary between rhombohedral and tetragonal phases occurred at x ∼0.4 rather than at x = 0.47 in bulk ceramics. This was attributed to clamping arising from mismatch in thermal expansion between the film and substrate.

We introduce the lasing principle and important characteristics of photonic-crystal surface-emitting laser (PC-SELs). Specifically, we demonstrate two-dimensional coherent lasing oscillation with GaN PC-SELs, using a unique crystal growth technique called “air hole retained overgrowth” (AROG). Above the threshold, we obtained a two-dimensionally distributed near-field pattern, and a distinctive far-field pattern with a divergence angle less than 1°. We also investigate a suitable sample structure for the reduction of the threshold current, where the PC structure is moved from an n-cladding layer to a p-cladding one. This is an important step towards the realization of novel light sources that can be integrated two dimensionally for a variety of new scientific and engineering applications in the blue to ultraviolet wavelengths.

The predictability of models describing long-term nuclear glass behavior in a geological repository can be tested by means of natural or archaeological analogs. This study covers fractured archaeological glass blocks from a shipwreck discovered near the Mediterranean island of Embiez (France). The blocks were examined mainly because of their morphological analogy with nuclear glasses. Fractured after production (as in the case of nuclear glass), these blocks had been leached for 1800 years in seawater. The laboratory investigation led to the development and subsequent validation on archaeological objects of a geochemical model capable of accurately simulating the coupling between chemistry and transport to account for the alteration state of the cracks according to their geometric characteristics. Laboratory experiments allowed us to determine the kinetic and thermodynamic parameters for modeling glass alteration. The model was then tested against short-term experiments before simulating the crack alteration over 1800 years. We show that cracks in the outer regions of the block are the most severely altered because of rapid solution renewal, whereas internal cracks are very slightly altered because of a rate-limiting effect of water transport due to the formation of secondary phases. This study also establishes a direct link between data obtained at lab scale and the long-term evolution of a complex system in a natural environment, indicating that the key phenomena have been identified experimentally. The analogous behavior of archaeological and nuclear glass during leaching experiments and the similarities in their crack networks allow us to consider applying the model to nuclear glasses under geological repository conditions. This study clearly shows that the internal crack network does not play a major role in the overall long-term alteration of archeological glass blocks. The issue of the transposition studies will be to determine whether this conclusion can be generalized to nuclear glasses.

Significant advances have been made in increasing the deposition rate of hydrogenated silicon germanium alloys (a-SiGe:H) using a modified VHF glow discharge deposition method while also maintaining good electronic properties important for its application in photovoltaic devices. We examine the electrical and optical properties of these alloys deposited either by RF (13.56MHz) or the modified VHF methods over deposition rates varying from 1 to 10 Å/s. The electronic properties of a series of 1.4 eV optical gap a-SiGe:H i-layers, in many cases in solar cell device configurations, were characterized. Drive-level capacitance profiling was used to determine the deep defect densities, and transient photocapacitance measurements allowed us to determine the Urbach energies. Results were obtained for both the annealed and light-soaked degraded states and these results were correlated to the cell performance parameters. In general the a-SiGe:H layers deposited using the modified VHF excitation exhibited improved electronic properties at higher growth rates than the RF deposited samples.

In spite of considerable efforts, flow control in micro-channels remains a challenge owing to the very small ratio of channel/supply-system volumes, as well as the induction of spurious flows by extremely small pressure or geometry changes. We present here a robust and complete system for flow control in complex microchannel network that both monitors and controls all the flow relevant parameters, that is to say flow rate and pressure.Based on a dynamic control of reservoir pressures at the end of each channel and external thermal flow-sensors, all the parameters are measured with a precision down to 25 μBar and 2nL/min. Thanks to adaptative feed back control loop, the MAESFLO can control either the flow rate or the pressure with high stability over long period whatever the microsystem characteristics. Compared to classic pumps, a significant increase of stability has been reached as no mechanical parts are involved. Indeed the flow rate is pulse free and is stable down to 0.1% of the full scale. Besides, pressure control enables to achieve short response time (less than hundreds of millisec).The MAESFLO is thus a unique system to control flow in complex network architecture and can be considered as an alternative to integrated micro-valves using only external equipments. Indeed, the MAESFLO can stop the flow to nearly zero in one or several branches of a complex microfluidic network while keeping other flows constant. Sequential manipulation of liquids in a definite part of a micro-device is thus possible without expensive and time consuming fabrication processes. It can be particularly useful when dealing with washing steps in the case of biological assay for example.Controlling flow with short response time along with high precision is also a key issue in microfluidic. By combining pressure actuation with flowrate monitoring, short response time are achievable keeping a high precision flow rate. It can be particularly useful for droplet generation and size control, droplet on demand generation, long time living cell perfusion and drug injection…In this work we will present the benefit to control and monitor both pressure and flow rate with the MAESFLO. A lot of information can be extracted from these simple parameters, as hydraulic resistance, monophasic and biphasic apparent viscosity, the volume and the position of a trapped air bubble and many more. The proof of concept of stop flow control will also be shown with experimental results stressing the advantages of the “virtual micro-valve”.

We have developed a program to connect students, as well as the general public, with glass science in the modern world through a series of hands-on activities and learning experiences using sucrose based glass (a.k.a. hard candy). The scientific content of these experiments progresses systematically, providing an environment to develop an understanding of glassy materials within a framework of “active prolonged engagement” with the material. Most of the experiments can be assembled in a high school lab, or even in a home setting with minimal cost, and yet are appropriate for inclusion in an undergraduate materials lab. The cost is minimized by utilizing common, everyday materials and devices. Some of the activities included in our experiments include: synthesis, density, refractive index determination, glass transition, crystallization, kinetics of devitrification, thermal properties, etc. Temperature measurement, temperature control, and even automated data collection are part of the experience, providing an open path for the students to continue their own interesting and creative ideas.

Electropolymerization of unsubstituted and substituted propylene - dioxythiophenes (i.e., ProDOT & ProDOT-Bz) on ( ˜7 μm diameter) single carbon fiber microelectrodes (SCFMEs) in different electrolytes resulted the network of nanopore structures.Surface morphology of coatings were investigated by Scanning Electron Microscopy (SEM), the attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was used for the characterization . Electrochemical impedance spectroscopic investigation of these nanostructures has been indicated the capacitive behavior of electrode system. Data were used to simulate at applied potential and explained by equivalent circuit modeling.

The reliability of InP/InGaAs heterojunction bipolar transistors (HBTs) with highly carbon-doped and zinc-doped InGaAs base layers grown by metal-organic vapor phase epitaxy has been investigated. The Raman spectroscopy reveals that the post-growth annealing for the carbon-doped InGaAs base improves the crystallinity to become as good as that of the zinc-doped InGaAs base. However, the photoluminescence intensity remains lower than that of the zinc-doped InGaAs even after the post-growth annealing. The current gains of the carbon- and zinc-doped base InP/InGaAs HBTs are 63 and 75, respectively, and they are affected by the base crystallinity. After the 15-min current stress test, the current gains decreased by 40 and 3% from the initial current gains for zinc- and carbon-doped base HBTs, respectively, are observed. These results indicate that the carbon-doped base HBT is much more reliable than that of zinc-doped base HBT, though it has a lower current gain.

This paper describes a modeling approach to target aspects of heat conduction in metal hydride powders that are essential to metal hydrides as viable H2 storage media, including particle morphology distribution, size distribution, particle packing properties at specified solid fraction, and effective thermal conductivity. An isotropic fracture model is presented that replicates features of particle size and shape distributions observed experimentally. The discrete element method is used to simulate evolution of metal hydride particle contact networks during quasi-static consolidation of decrepitated metal hydride powders. Finally, the effective thermal conductivity of such a powder is modeled assuming that contact conductance is the same for each interparticle contact.

There are many factors that have the potential to limit significant advances in device technology. These include the ability to arrange materials at shrinking dimensions and the ability to successfully integrate new materials with better properties or new functionalities. To overcome these limitations, the development of advanced processing methods that can organize various combinations of materials at nano-scale dimensions with the necessary quality and reliability is required. We have explored using a gallium focused ion beam (FIB) as a method of integrating highly mismatched materials with silicon by creating template patterns directly on Si with nanoscale resolution. These templates are potentially useful as a means of locally controlling topography at nanoscale dimensions or as a means of locally implanting Ga at specific surface sites. We have annealed these templates in vacuum to study the effects of ion dosage on local Ga concentration and topography. We have also investigated the feasibility of creating Ga nanodots using this method that could eventually be converted to GaN through a nitridation process. Atomic force microscopy and electron microscopy characterization of the resulting structures are shown for a variety of patterning and processing conditions.

The early stages of plasticity in KBr single crystals have been studied by means of nanometer-scale indentation in complementary experiments using both a nanoindenter and an atomic force microscope. Nanoindentation experiments precisely correlate indentation depth and forces, while force microscopy provides high-resolution force measurements and images of the surface revealing dislocation activity. The two methods provide very similar results for the onset of plasticity in KBr. Upon loading we observe yield of the surface in atomic layer units which we attribute to the nucleation of single dislocations. Unloading is accompanied by plastic recovery as evident from a non-linear force distance unloading curve and delayed discrete plasticity events.

A polymeric chelating ligand containing hydroxamic acid and amidoxime functional groups were prepared from acrylate polymer grafted acacia cellulose and this ligand was introduced to remove heavy metals from industrial wastewaters. The heavy metals binding property with this ligand is excellent up to 3.78 mmol/ g sorbent and the rate of exchange of some metals was very fast i.e. t½ ≈ 6 min (average). Two types of wastewater from electroplating plants used in this study those containing chromium, zinc, nickel, copper and iron etc. Before removing heavy metals from wastewater, pH was adjusted to 4 and various metal concentrations were used for finding the extraction capability of the ligand. It was found that the metals recovery was highly efficient, up to 99.99% of several heavy metals were removed from electroplating wastewater using the ligands. Therefore, the proposed polymeric chelating ligands could be used to the remove such heavy metals from industrial wastewater and as well as effective ligands for environment protection.

We applied the deactivation treatments to p-type single crystalline silicon solar cells for deactivating the recombination-active boron-oxygen complex. The methods we used include thermal annealing treatment, capacitively couple plasma (CCP) treatment, and plasma immersion ion implantation (PIII) treatment. The results showed that all the deactivation treatments were working and the energy transfer efficiency (Eff) was thereby increased by more than 1% absolute compared to the degraded state base on the increasing of the open-circular voltage (Voc) and short-current density (Jsc). The CCP deactivated treatment got better efficiencies than PIII treatment because the PIII treatment damaged the surface of solar cells. After the forming gas treatment, the samples could be improved to close to the PIII samples due to the surface damage repairing. However, the increased efficiency could not be kept and would be degraded again after illumination.

Monodispersed ceria coated silica particles were prepared by a new type of ceria precursor. The ceria precursor was synthesized by alkoxide method, which employs ethanol as solvent. The synthesized particles were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It was found that well-crystalline ceria coatings were deposited on the surface of the silica particles without post-heat treatment. In addition, the coated particles prepared by a new precursor were uniformly dispersed without the formation of hard aggregate as compared to those obtained by conventional method.

Titanium dioxide (TiO2) nanostructures are widely employed in photoconversion processes. In particular titanium dioxide nanotubes (TNTs) have shown promise in many applications including solar cells. While there are methods for making TNT films the preparation of high surface area small diameter (<10nm) TNT films is a challenge. We have now prepared TNT films by pulsed laser deposition (PLD) of P25 and P90 TiO2TiO2 nanoparticles onto stainless steel foils followed by a hydrothermal treatment. The best results were obtained when the TiO2TiO2 films were deposited at 500°C. Subsequent hydrothermal treatment at 150°C results in a dense mat of TNTs that are ˜10 nm in diameter with a pore size of ˜5 nm. The TNTs were further functionalized with quantum dots including PbS with controlled particle size and location to access a greater portion of the solar spectrum. The titanium oxide nanotube/ quantum dot films were characterized by SEM, TEM, XRD UV-Vis and Raman spectroscopy. Preliminary results for the formation and characterization of solar cells using the TNT films will be described.