Cyclic voltammogram studies were performed on H2SeO3, CuSO4, In2(SO4)3, GaCl3, H2SeO3 + CuSO4 + In2(SO4)3 and H2SeO3 + CuSO4 + In2(SO4)3 + GaCl3 to understand the electrodeposition mechanism. The reduction potential from the cyclic voltammogram studies indicates that the first deposited layer is Cu from the Cu-In-Se and Cu-In-Ga-Se solution mixture. The subsequent deposition of the In and Ga layer is more favorable on the first-deposited Cu layer.

Organic conducting and semiconducting materials are promising as thermoelectric conversion materials in flexible and wearable electronics because they have large Seebeck coefficients and small thermal conductivities. Since there have been only a limited number of studies on the thermoelectricity of organic materials to date, precise evaluation of Seebeck coefficient and electrical conductivity of various organic conducting/semiconducting thin films is important to examine what kind of material is the most effectual. To carry out such experiments, a specially designed instrument for organic thin films has been developed. Its ability to measure Seebeck coefficients of highly resistive materials was confirmed and Seebeck coefficients and power factors of several typical organic functional materials were preliminary evaluated.

The freshwater Zebra Mussel, Dreissena polymorpha, was accidently released into the Great Lakes approximately 20 years ago. Since then it has spread rapidly, thanks in part to its ability to adhere to hard substrates, resulting in serious environmental and economic consequences. Like the marine mussels, attachment of the Zebra Mussel is achieved by means of its byssus, a series of proteinaceous threads that connect the animal to surfaces via secreted adhesive plaques. While the byssus of the Zebra Mussel is superficially similar to those of its marine counterparts, significant structural and compositional differences suggest that further investigation of the adhesion mechanisms in this freshwater species is warranted. Here we examine for the first time the detailed distribution of DOPA (3,4-dihydroxyphenylalanine)-containing proteins in the Zebra Mussel plaque and threads, as well as the enzyme responsible for their cross-linking. We show that the plaque-substrate interface retains the greatest amount of DOPA after aging, consistent with an adhesive role, while in the threads and bulk of plaque DOPA is presumably cross-linked for cohesive strength. We report also on a remarkably uniform layer ˜10 nm thick on the underside of the plaque, which is most likely responsible for adhesion.

The paper describes the studies of the transformation of Cs+- and Sr2+-containing zeolite sorbents synthesized from fly ash cenospheres to crystalline mineral composition, suitable for the long-term disposal. Series of Cs+- and Sr2+-exchanged NaP1-containing sorbents were subjected to the thermochemical transformation in the temperature range 40-1100°C at atmospheric pressure in air and the progress of reaction was monitored by DSC and XRD analysis. It was shown that initial sodium zeolite undergoes two-step transformation at 736-785°C and 892-982°C forming nepheline as the principle product, with the conversion temperatures being dependant on the heating rate.

The thermal treatment of Cs+-bearing zeolite sorbent led to formation of a complex multiphase system, the principal components of which were nepheline and pollucite. Increasing cesium content in the samples led to a monotonous shift of crystallization peak to the higher temperature range (1005-1006°C). A more complicated behavior was observed for Sr2+-containing samples, for which the crystallization temperature tends to increase (compared with NaP1) at lower Sr contents, but it starts decreasing parallel to the Sr2+ content at Sr2+ loadings >10 mg/g. The principal crystalline phases in Sr-NaP1 sample conversion were nepheline and Sr2+-containing feldspar, the quantity of which increased parallel to the increase of strontium content in zeolite.

Apparent activation energies of thermochemical transformations were calculated and possible approaches to reduce transformation temperature are discussed and experimentally illustrated.

In this paper the impact of post deposition annealing in various ambient on electrical properties of hafnium zirconate (HfxZr1-xO2) high-k dielectrics is reported. ALD HfxZr1-xO2 films are annealed in a nitrogen and/or oxygen ambient at 500°C to 1000°C. Devices annealed at 500°C in N2 has lower equivalent oxide thickness (EOT) of 10Å without significant increase in gate leakage (Jg), threshold voltage (Vt) and only a slight decrease in transconductance (Gm) values compared to 500°C O2 annealed devices. Furthermore, the impact of annealing HfxZr1-xO2 films in a reducing ambient (NH3) is studied. Optimized NH3 anneal on HfxZr1-xO2 results in lower CET, improved PBTI, low sub-threshold swing values, comparable high-field Gm with only a minor degradation in peak Gm compared to control HfxZr1-xO2. Finally, the impact of laser annealing vs. RTP annealed HfxZr1-xO2 films are reported. Laser annealing helped further stabilize tetragonal phase of HfxZr1-xO2 without inducing void formation. Good devices with low leakage, low EOT and high mobility are obtained for laser annealed HfxZr1-xO2.

The super-molecular structure and morphology of shape-memory polymers (SMP) have an evident influence on the shape-memory effect (SME). More detailed information on these structure-function relations during the dynamic processes of programming and shape recovery are required to better understand the SME. Here we explore whether wide and small angle x-ray scattering (WAXS, SAXS) in combination with deformation experiments can help to characterize and better understand the respective materials super-molecular structure (spatial organization of chain segments in crystalline and non-crystalline regions, characterized by parameters such as crystallinity, crystallite-sizes, domain-sizes and -arrangements) and its changes upon varying mechanical loads and temperature increase as stimulus. Multiphase polymer networks based on poly(ε-caprolactone) and poly(cyclohexyl methacrylate), whose molecular structures allow formation of at least two separated domains, were investigated using WAXS and SAXS, to describe the respective super-molecular structures and morphologies and their development during cyclic, thermomechanical tensile tests reproducing key features of shape-memory programming and recovery.The creation of the triple-shape capability for this AB polymer network system is performed by a one-step process, which is similar to a conventional dual-shape programming process. It could be shown via SAXS that a long period between crystalline domains exists for these polymer networks. The value of this long period changes by some nanometers as a consequence of programming and the resulting elongation of the respective sample. Further insights could be obtained by investigating WAXS diffraction peaks, detected at different steps during the thermomechanical treatment. It could be shown that crystal sizes in this polymer system remain unaffected by the programming process, while the crystallization of the stretched samples during the cooling process leads to a spatial rearrangement (preferential orientation) of crystalline domains.

Current trends in sensing and diagnostics is towards developing hybrid devices that incorporate nanomaterial for enhancing device performance. These devices and systems have a broad impact ranging from personalized medicine in health care, environmental sensing and building multifunctional sensors for military applications. The overarching objective of the research work is to develop a new class of portable, bio-analytical tools with improved functionality and performance capabilities by utilizing the electrical effects on cellular and sub cellular species in micro and nanoscale domains.

There are two key ideas underlying this research work. The first is to design and manufacture structures comprising of nanoscale-confined spaces integrated on to multi-scale architecture platforms. This model architecture has been engineered to harness the principle of macromolecular crowding for biomolecule binding and detection by monitoring perturbations in the electrical bi-layer in tailored nanoscale confined spaces. Enhanced performance metrics in biomolecule detection have been demonstrated in developing electrical immunoassays. We have demonstrated picogram/ml sensitivity in detection of specific cardiovascular disease biomarkers, cancer biomarkers from human serum samples with a dynamic range of response varying frompg/ml to g/ml and response time within 120 seconds.

Today the requirements for reducing the impact of our manufacturing activities are increasing as the world awakes to and addresses the environmental impacts of our society. Energy consumption, greenhouse gas emissions, materials availability and use, environmental impact levels, etc. are all topics of interest. Semiconductor manufacturing in general and process steps such as CMP are not exempt from this and, in many cases, the industry has led the efforts in reducing impacts. This paper will first review some of the drivers for sustainable manufacturing, then define some of the terms that will be useful for determining the engineering aspects of sustainability and sustainable manufacturing, as well as metrics for assessing the impact of manufacturing in general and CMP in particular. An assessments of CMP will be given to illustrate the potential for “design for the environment” in CMP and related processes. Consideration will be given to research opportunities, including process modeling, that this focus provides to CMP researchers, consumable suppliers and industry.

Considerable amount of works have been reported to achieve a high breakdown voltage of AlGaN/GaN heterostructure devices by employing additional process such as SiO2 passivation1,2, floating metal rings and Ni/Au Oxidation3. However, it should be point out that treatment of passivation layer of AlGaN/GaN heterostructure devices has been reported scarcely. As+ ion implantation on SiO2 passivation layer may be a simple and effective to reduce electric field strength to increase breakdown voltages.The cross-sectional view of the proposed AlGaN/GaN Schottky barrier diode is shown in Fig. 1. We fabricated conventional AlGaN/GaN Schottky barrier diode and passivated the device with SiO2 layer of 350 nm thick. Finally As+ ions were implanted on the SiO2 passivation layer. We measured the surface potential of the test samples with electric force microscopy (EFM) in order to verify that implanted As+ ions remained as positively charged ions in SiO2 layer after ion implantation. After ion implantation, 2 dimensional electron gas (2DEG) concentration was increased slightly from 8.28E12 /cm2 to 8.38E12 /cm2 so that the forward current was also increased slightly. Table shows the breakdown voltages of the SBDs before and after As+ ion implantation. After As+ 80 keV 1 × 1E14 atoms/cm2 implantation, the breakdown voltage increased considerably from 604 V to 1204 V due to the edge termination by implanted As+ ions. The reverse leakage current decreased from 80.3 uA/mm to 21.2 nA/mm due to the relaxation of electric field concentration by As+ ion implantation. We verified the electric field relaxation through 2D simulation. After As+ ion implantation, the depletion region curvature under the reverse biased condition became moderate so that the maximum electric field strength was decreased.As+ ion implantation method may be a simple and effective edge termination method for improving the breakdown voltage as well as the leakage current of the proposed AlGaN/GaN SBDs. Proposed AlGaN/GaN SBDs showed high breakdown voltage of 1204 V and low leakage current of 21.2 nA/mm without any considerable decrease of forward characteristics while that of conventional device was 604 V and 80.3 uA/mm, respectively.

Antibody-functionalized, Au-gated AlGaN/GaN high electron mobility transistors (HEMTs) were used to detect Perkinsus marinus. The antibody was anchored to the gate area through immobilized thioglycolic acid. The AlGaN/GaN HEMT were grown by a molecular beam epitaxy system (MBE) on sapphire substrates. Infected sea waters were taken from the tanks in which Tridacna crocea infected with P. marinus were living and dead. The AlGaN/GaN HEMT showed a rapid response of drain-source current in less than 5 seconds when the infected sea waters were added to the antibody-immobilized surface. The recyclability of the sensors with wash buffers between measurements was also explored. These results clearly demonstrate the promise of field-deployable electronic biological sensors based on AlGaN/GaN HEMTs for Perkinsus marinus detection.

Tb-doped Li2O-LaF3-Al2O3-SiO2 (LLAS) glasses containing silver were fabricated using melt-quenching technique. Silver nanoparticles (NPs) in glass matrix were confirmed by optical absorption and X-ray diffraction (XRD). The nucleation of silver NPs was controlled by heat-treatment. A broad absorption band peaked at about 420 nm was observed due to surface plasmon resonance (SPR) of the silver NPs. This SPR absorption of silver NPs increases with the time of heat-treatment. Photoluminescence (PL) emission and excitation spectra were measured on Tb-doped LLAS glasses with and without silver NPs. Strong Tb3+ luminescence was observed. For excitation at 325 nm, luminescence of Tb3+ ions increases for the glass containing silver NPs compared to that in the glass without silver NPs. After further heat-treatment at 520 °C for 5 hours, Tb3+ luminescence decreased. Our luminescence results suggest that there are two competitive effects, enhancement and quenching effects, acting on Tb3+ luminescence in the glass containing silver NPs. The enhancement of Tb3+ luminescence is attributed to local field effects due to the excitation of SPR of silver NPs. The quenching effect in the presence of Ag NPs suggests an energy transfer from Tb3+ ions to silver NPs exists, which may provide an additional non-radiative relaxation pathway for the excited Tb3+ ions.

Small-scale natural fibers are among the biological materials being studied by researchers seeking innovative methods to create new high performance materials. For example, spider dragline silk fibers are being studied because of their unique combination of high strength-to-weight ratio and high extensibility, which leads to a tough and lightweight fiber. Biomimetic fibers based on spider silk have been a focus of research for the past decade. However, there are still many unanswered questions about the mechanisms by which silk achieves its unique mechanical properties, as well as challenges in mechanical testing of biomimetic silk fibers (which is often hindered by both small diameters and limited material availability). A method to characterize local mechanical behavior in small diameter fibers was developed to both improve understanding of structure-property relationships in natural fibers and provide a method for comparing mechanical behavior in natural and biomimetic fibers. The deformation mapping technique described in this paper, which utilizes a piezoelectric micromanipulator with pulled glass tips, an inverted microscope with attached camera, and an image processing MATLAB program, is also applicable to the characterization of other micro- and nanoscale fibers where local deformation mechanisms may be of interest (e.g., for mechanical characterization of electrospun fibers).

Sn3O4 nanobelts were grown by a carbothermal evaporation process of SnO2 powders in association with the well known vapour-solid mechanism (VS). The nanobelts crystal structure was investigated by x-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), raman spectroscopy and field emission gun scanning electron microscopy (FEG-SEM). The structural and morphological characterization has confirmed the growth of single crystal nanobelts. The electrical characterization (current-voltage, temperature-dependent resistance curves) of individual Sn3O4 nanobelts was performed at different temperatures and light excitation. The experiments revealed a semiconductor – like character as evidenced by the resistance decreasing at high temperatures. The transport mechanism was identified as the variable range hopping.

Effective indenter concept was introduced by Pharr and Bolshakov to explain nanoindentation unloading curves. This paper shows that the contact stiffness under a uniform pressure distribution is 57% higher than what is given by the fundamental relation. This is due to the fact that there is no physical indenter that gives a uniform pressure distribution during elastic contact, and the fundamental relation used in nanoindentation data analysis does not apply.

Alternative energy sources such as thin film photovoltaics can be accelerated by improving the rapid and successful transition from laboratory research innovation to commercial production. Most laboratory research and development is on a small scale and its production is in small volumes. It focuses on exploration, discovery, and understanding. When the successful innovation is commercialized, both the scale and the volume increase dramatically and the focus shifts to performance, reliability, yield and cost. This transformation can be accelerated by closely managing risk and by integrating the equipment design and the process development. Also, the cadmium telluride photovoltaic technology has properties that make it more amenable to rapid scale up to low cost and high volume manufacturing.

Periodic wrinkles or corrugations can appear on the free surfaces of constrained hydrogel films. The constraint generates a residual compressive stress that is partially relieved through deviation of free surfaces from a planar configuration. The morphology, amplitude and wavelength of the surface instability are generally well-defined and depend on the strength of the constraint. If swelling of the hydrogel overcomes the constraint, the film can slip along its substrate, altering the resultant compressive stress and surface topography. By tuning this slippage, we aim to direct the surface features presented by thin hydrogel films. Active control of surface morphology could have important implications in several applications ranging from sensors to controlled cell attachment and detachment.

In this work, we discuss a method of tuning the amount of slippage and surface topography of patterned poly(N-isopropylacrylamide) (poly-NIPAAm) films. The films were fabricated from photo-crosslinkable polymers comprising NIPAAm and photo-active methacroyloxy-benzophenone (MaBP) monomers. The patterned films were anchored to a substrate through a hydrogen-bonding self-assembled monolayer. The relationship between pattern geometry, pattern dimensions, and solvent were investigated with respect to the mechanical instability generated at the free surface. We observed that the wavelength, width, and amplitude of the instability always increased with the thickness of the polymer pattern. The morphology of the surface instability, however, was especially sensitive to thickness of the pattern, the solvent, and the spatial position with respect to the edge of polymer pattern. If the slippage of the film against the substrate is minimal, a wrinkle pattern in the form of bicusps was observed. If the compressive stress exceeded the hydrogen-bonding anchors, slippage of the film generated either a blister pattern or a honeycomb pattern.

Fluorapatite (Fap), Ca10(PO4)6F2, could be a potential candidate for the immobilization of radioactive isotopes thanks both to its physical-chemical properties and to the capability to incorporate mono-, di- and trivalent cations in its crystal structure. In this research work different preparation procedures able to incorporate in a fluorapatite matrix strontium in the form of nitrate or fluoride salt were considered. The experiments were performed by means of stable isotopes, as representative of the radionuclides contained in the nuclear fuel. Subsequently, the Sr-substituted fluorapatites (SrxFap), Ca10-xSrx(PO4)6F2, were characterized by X-ray diffraction, Raman spectroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The results suggest that the considered synthetic procedures could be reasonably applied to the confinement of the radionuclides contained in some types of nuclear waste. In order to avoid the presence of unreacted reagents in the products or the formation of undesired phases, an optimization of the synthetic procedures may be considered.

We have investigated relationships between leakage current and microstructure or domain structure of BiFeO3 (BFO) thin films, and leakage current mappings of BFO thin films have been performed by current sensitive AFM. 350-nm-thick and 250-nm-thick BFO thin films were prepared on Pt/TiO2/SiO2/Si substrate by pulsed laser deposition (PLD) and chemical solution deposition (CSD), respectively. Average grain size of PLD-BFO thin film is about 480 nm, which is the same as the film thickness. From the leakage current mapping at a bias voltage of -16 Vdc, leakage current of the BFO thin film flows through not only grain boundary but also the grain itself. On the other hand, CSD-BFO thin film shows rosette structure and small size grains. From the leakage current mapping at a bias voltage of -10 Vdc, leakage current flows along boundaries of the rosette structures. These results indicate that leakage current of BFO strongly depends on its microstructure.

We report on single dot photoluminescence imaging and spectroscopy at B=0T on magnetically doped CdMnTe self-assembled quantum dots with average Mn concentration of several percent. Quasi-resonant excitation with circularly polarized laser leads to formation of magnetic polarons with magnetization induced by the laser light. In this case all quantum dots are polarized in the same direction. In contrast, when the dots are populated using above the barrier excitation, with randomly polarized excitons, the resultant magnetization is random and varies from dot to dot. These experiments demonstrate a way to control the magnetization of magnetically doped quantum dots by means of light excitation. In addition, they point towards extremely long spin memory times in these structures, reaching hundreds of microseconds, making CdMnTe quantum dots promising candidates for local magnetic field sources on the nanoscale.

n-ZnO/i-CdZnO thin film was grown on p-type Si substrate by plasma-assisted molecular-beam epitaxy (MBE). Rectifying I-V curves show typical diode characteristics. Cyan electroluminescence emissions at around 473 nm were observed when the diodes were forward-biased at room temperature. The emission intensity increases with the increase of the injection current. Room temperature photoluminescence verifies the electroluminescence emissions come from CdZnO layer.