As critical dimensions decrease, key dimension-related dielectric etch challenges emerge, including via and trench uniformity and etch depth profile. The transition to ultra-low-k films such as BDIII (Black Diamond; k=2.55) dielectrics requires consideration of film sensitivity to compositional modification, polymer interactions at pores, and the effect of diffusion. Use of N2/O2 plasma at 60 ˚C to modify the M1 trench profile has been demonstrated to lower the RC delay by 14% as compared to traditional CO2 plasmas at 60˚C. Use of a DHF solution to clean the etching residue in the dual damascene structure results in >97% yield with a tight range of via chain resistance.

By incorporating a localized heating system within a scanning ion-conductance microscopy (SICM) system, we have performed stable ‘hopping-mode’ (HPICM) imaging for live cells maintained at temperatures ranging up to human body temperature. This allows the accurate study of cell volume and morphology variation versus temperature over extended periods of time. The integration of SICM with scanning electrochemical microscopy (SECM) provides the simultaneous mapping of electrochemical and topographic information for soft samples, such as live cells. This combined technique overcomes the limitations of resolution and topographical artifacts typically associated with SECM. However, previously reported SECM-SICM probe production required expensive and time-consuming focused ion beam (FIB) methods and produced pipettes that are typically hundreds of nanometers in diameter. We report a simple and rapid production method for SECM-SICM double-barrel probes with apertures down to 20 nm in diameter. The characterization of these SECM-SICM probes using scanning electron microscopy (SEM) imaging, cyclic voltammetry (CV) and Raman spectroscopy is also detailed. These SECM-SICM probes were subsequently used to study the morphology and electrochemical activity of several samples, ranging from hard metallic/insulating samples to live cells.

The typical architectures for single-transistor capacitorless dynamic random access memory (1T-DRAM) are reviewed. This memory takes advantage of floating-body effects in SOI-like devices. The principles of operation and the key mechanisms for memory programming and reading are described. Most of these devices can be enriched with non-volatile storage capability. Several possibilities for such ‘unified’ memory are explored.

We compare the characteristics of ferrogels prepared with and without the presence of a uniform magnetic field using Fe3O4 and Fe2O3 nanoparticles immobilized in hydrogels of N-isopropylacrylamide. The spatial distribution and agglomeration of the nanoparticles within the ferrogels were investigated using ultra small angle x-ray scattering (USAXS) and transmission electron microscopy (TEM). Hydrated ferrogels were also studied for magnetization using direct current superconducting quantum interference device (DC-SQUID). Volume size distribution resulting from USAXS data of the Fe3O4-ferrogel prepared under a uniform 225 G magnetic field showed a single broad peak appreciably different from that prepared without magnetic field with three distinct peaks. Volume size distributions resulting from USAXS data of the Fe2O3-ferrogel prepared with and without the presence of a uniform magnetic field both similarly show two peaks. Nanoparticle agglomeration was also determined by analyzing TEM images of ferrogel samples. DC-SQUID measurements of Fe3O4-ferrogel prepared in the presence of a uniform magnetic field showed 9% higher magnetization compared to the Fe3O4-ferrogel prepared without magnetic field. Similarly, DC-SQUID measurements of Fe2O3-ferrogel prepared in the presence of a uniform magnetic field showed 3% higher magnetization compared to the Fe2O3-ferrogel prepared without magnetic field. Thus, the presence of a uniform magnetic field during ferrogel polymerization can enabled the enhancement of the magnetoelastic property of the ferrogel.

The behavior of Eurobitum bituminized radioactive waste under geological disposal conditions is studied in water uptake tests at the Belgian Nuclear Research Centre SCK•CEN to assess the feasibility of geological disposal for the long-term management of this waste. The hydro-mechanical behavior of this waste is affected by the continuous evolution of the rheological properties of bitumen due to radio-oxidation (i.e. ageing).

The effect of the bitumen ageing degree on the kinetics of the water uptake, swelling and NaNO3 leaching is investigated in water uptake tests with ∼30 years old radioactive samples and inactive samples that were artificially aged. The first results of swelling and NaNO3 leaching of (i) radioactive samples that have been hydrated for more than 2 years at a constant total stress of 2.2 MPa, and (ii) a thermally aged sample that has been hydrated for ∼1.5 years under nearly zero effective stress conditions, revealed lower swelling and higher leach rates for these samples compared to non-aged samples. The effect of ageing on the osmotic efficiency of bitumen as a semi-permeable membrane is less pronounced when swelling of the samples is limited, and changes in time, probably because of the formation of low porosity layers, which seems to mask the difference in bitumen membrane efficiency of aged and non-aged bituminized waste.

Colloidal particles (CPs) have been the subject of intensive studies and have attracted increasing attention from the scientific community. In this contribution, we present the design and synthesis of luminescent colloidal crystal films. Rare earth complexes as the photoluminescent source is introduced into the polymeric nanospheres system, the diameter can be controlled by changing the polymeric reaction condition, which can act as building blocks to prepare diverse functional materials. Further, three-dimensional (3-D) colloidal crystal films with excellent fluorescent properties are fabricated by self-organization of the monodispersed polymeric nanospheres. The colloidal crystal film indicates a photonic band gap, which depends on the diameter and size-dispersing of the nanospheres building blocks. It shows potential applications in fabricating optical devices, data storage, chemical and biological sensors, and color displays.

Charge trapping and slow (10 s to > 1000 s) detrapping in AlGaN/GaN HEMTs designed for high breakdown voltage (> 1500 V) are studied to identify the impact of Al molefraction and passivation on trapping. Two different trapping components, TG1 (Ea = 0.62 eV) and TG2 (with negligible temperature dependence) in AlGaN dominate under gate bias stress in the off-state. Al0.15Ga0.85N shows much more vulnerability to trapping under gate stress in the absence of passivation than does AlGaN with a higher Al mole fraction. Under large drain bias, trapping is dominated by a much deeper trap TD. Detrapping under illumination by monochromatic light shows TD to have Ea ≈ 1.65 eV in Al0.26Ga0.74N and Ea ≈ 1.85 eV in Al0.15Ga0.85N. This is consistent with a transition from a deep state (Ec - 2.0 eV) in the AlGaN barrier to the 2DEG.

Perfectly (111)-oriented rhombohedral Pb(Zr, Ti)O3 [PZT] films were successfully grown on (111) CaF2 substrates. These films have the polar-axis perpendicular to the substrate surface without non-180o domains. Well saturated polarization (P) –electric field (E) hysteresis loops were observed at various frequencies and temperatures. Temperature dependence of the saturation polarization (P sat.) was in good agreement with the estimated one by Haun et al. using phenomenological approach but did not strongly depend on the measured frequencies. On the other hand, the coercive field (Ec ) increased with decreasing temperature and with increasing the measurement frequency.

Nonlinear optical effects are revealed when strong light fields interact with matter. It has been shown that nanomaterials exhibit properties which are very different from the bulk, and in many cases, the nonlinear optical (NLO) efficiency of nanomaterials is found to be higher in comparison. Recently there has been substantial interest in developing novel NLO media for various applications. Even though several organic as well as inorganic materials have been studied in this connection, only a limited number of NLO reports exist for oxide nanomaterials. Therefore, in this paper we present results of NLO measurements recently conducted in our laboratory in three different oxide nanosystems. It is found that oxide nanomaterials are generally robust, and exhibit good NLO efficiencies, which make them potential candidates for photonic and optoelectronic applications.

This work presents the successful production, via a simple oxidation process, of Ti-TiOx-Pt Metal-Oxide-Metal diodes with excellent electrical asymmetry. TEM analysis has been used to verify the oxide thickness. A thicker layer produces better diodes, although they are of a less uniform nature. The conduction mechanism in these diodes is still under investigation.

Photoelectrodeposition of copper on boron-doped diamond films (BDD) was investigated. In this work, two different doped films were analyzed. Copper particles were deposited in the potentiostat mode and under UV irradiation. The BDD film as-grown and the BDD film modifed with Cu (Cu/BDD) on the surface were characterized by Raman Spectroscopy and Scanning Electron Microscopy (SEM) respectivily. These electrodes were tested as electrocatalysts for nitrate reduction in Britton-Robinson buffer solution (pH=3). Electrochemical measurements showed that the electrode with high doping level displayed the best electrocatalytic activity.

The economical production of flexible, chemically-functionalized carbon nanotube (CNT) electrodes is appealing for the manufacture of electronic textiles with integrated charge storage capability. In this paper, a commercial CNT sheet is treated with 0.02 M potassium permanganate at room temperature to accomplish in-situ deposition of manganese dioxide. The morphology, elemental oxidation states, and crystallinity of the modified CNT sheet are studied using SEM, EDX, XPS, and XRD. Manganese loading is varied from 4 to 20 weight-percent by tuning solution treatment time, and metal oxide hydration state is influenced by thermal annealing at 200 °C. Electrochemical measurements reveal that charge is stored not only via CNT-induced electrical double-layer capacitance, but also through metal oxide-mediated Faradic reactions. The MnO2-decorated CNT sheet exhibits a specific capacitance of 89.6 F/g at 1 A/g, a tenfold enhancement compared to pristine CNT sheet. Overall, this simplified processing approach holds promise for cost-effective incorporation of electrochemical capacitors into functional fabrics for energy-generation applications.

Polyurethane (PU) materials are used in a wide variety of implantable devices and technologies, e.g. stents, breast augmentation, nose surgery and bladder reconstruction. Despite the excellent chemical control for manufacturing bulk materials and the good biocompatibility, a major challenge remains interfacing of PU with biological environments. A chemically controlled surface engineering approach could improve desired protein adsorption processes and cellular interactions within different tissues, preventing uncontrolled events of the implant especially in early stages shortly after surgical procedures.

To gain better control over the PU surfaces we polymerized different bulk PU materials and developed a transfer-nanolithography technique to deposit inorganic Au-nanoparticles with defined structural features on the PU surface. Different nanoparticle patterns were transferred and analyzed by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). Topographical features of PU substrates were investigated by atomic force microscopy (AFM). Transferred Au-nanoparticles showed high stability on PU substrates even under extreme sonication conditions. In a final step, those nanoparticles were functionalized with peptides to facilitate cellular adhesion under physiologically relevant conditions. As proof of concept, rat embryonic fibroblast cells were cultured on a peptide functionalized PU interface and investigated by SEM.

In conclusion, we developed a versatile method to prepare nanostructured and biofunctionalized PUs. These PUs showed good stability characteristics and in vitro biocompatibility in cell culture assays.

This work investigates a novel method to enhance light trapping within polycrystalline silicon (poly-Si) thin films for photovoltaic applications. The method combines the use of hydrogen ion implantation for creation of surface textures in poly-Si thin films and the deposition of silver nanostructures on the textured surface. Poly-Si thin films were prepared by solid phase crystallization of amorphous silicon (a-Si) layer deposited on a SiO2/Si substrate. The a-Si was annealed at various temperatures 600 -1050 °C for 48 hours to grow grains of different size in p-Si, as confirmed by x-ray diffraction (XRD) measurements. These samples were then implanted with 20-keV hydrogen ions to a dose of 1017/cm2, and some with an additional implant with 90-keV argon ions to a dose 5×1015 /cm2. Following implantation, these samples were annealed in an Ar ambient at different temperatures. Surface blistering effects were observed using an optical microscope. Optical specular reflection measurements in the spectral range 400-1100 nm indicated that the reflectance of the samples with higher blistering had decreased remarkably from 40% to 10%. Lastly, the poly-Si samples with various textures were deposited with silver thin film followed by annealing in nitrogen ambient for forming Ag nanostructures on textured poly-Si surfaces. Scanning Electron Microscope (SEM) was used to image the surface structures. The formation of Ag nanoparticles on the poly-Si surface, with textures created by implantation followed by low-temperature annealing (e.g., 400 °C), can significantly reduce light reflection as opposed to the case with Ag nanoparticles formed on an un-textured, poly-Si surface.

The manufacture of composite materials can improve the properties of proton-conducting polymers as membranes in PEM fuel cells. We have investigated composite membranes obtained by dispersion of nanodiamond particles in a sulfonated PolyEtherEtherKetone (SPEEK) matrix. SPEEK is a major proton-conducting aromatic polymer. Nanodiamond has been studied for various applications and can be functionalized with different surface groups. For use in proton-conducting membranes, surface functionalization with proton-donating groups is a promising approach. In this preliminary work, we have studied the properties of membranes made using pristine nanodiamond from diverse origins for a first assessment of the potential properties. The composites were analysed by various techniques, including Thermogravimetric Analysis, water vapor uptake and mechanical tensile tests.

Maya blue is an organic / inorganic pigment which is composed principally by two elements: a white clay known as palygorskite (in the Mayan dialect Sakalum), and a blue dye called indigo, this dye is extracted from the plant Indigofera suffruticosa. The mixture and the warming of these two elements produce the Maya blue, which exhibits unusual features such as: resistance to the assault of the acids in warm or high temperatures, his persistent color in spite of having been exposed to different climatic conditions as a result of the passage of time and the specific chemical composition that this pigment presents.

In the present investigation natural indigo, palygorskite and synthetic maya blue were analyzed with a new implementation technique called photoacoustic analysis, which detects the structural changes that happen in the material under a controlled increase of temperature. Due to the fact that this technology detects with clarity where the structural changes happen but not that type of changes happen, it used as base termogravimetric analysis. One of the important findings, it was that in the spectrum of the synthetic maya blue were detected the structural changes of the clay and the dye, something that with other used technologies had not been achieved to observe.

Substrates with extremely low roughness to allow the growth of good-quality silicon material but that nevertheless present high light trapping properties are presented. In a first application, silver reflectors are used in single and tandem-junction amorphous silicon (a-Si:H) solar cells. High initial (stable) efficiencies of 10.4 % (8.1 %) for single-junction a-Si:H cells on glass and 11.1 % (9.2 %) for tandem-junction a-Si:H/a-Si:H cells on plastic are obtained. A second application better suited to multi-junction solar cells based on microcrystalline silicon (μc-Si:H) solar cells is presented: the substrate consists of rough zinc oxide (ZnO) grown on a flat silver reflector which is covered with a-Si:H; polishing of this structure yields an a-Si:H/ZnO interface that provides high light scattering even though the cell is deposited on a flat interface. We present results of ∼ 4-μm-thick μc-Si:H solar cells prepared on such substrates with high open-circuit voltages of 520 mV. A large relative efficiency gain of 20% is observed compared to a co-deposited cell grown directly on an optimized textured substrate.

BiFeO3 nanopowders with a size distribution around 20nm and optical absorption onset at 2eV have been synthesized using self-combustion. These particles were used to photodecolourise RhB under AM1.5 irradiation. XPS showed changes to the oxidation state of the Fe cations. Under AM 1.5 illumination at pH 2 RhB showed >95% decolourisation after 10minutes.

The glass transition temperature T g , crystallization temperature T x , solidus temperature T m , and liquidus temperature T l , of a number of ternary Cu-Hf-Ti glassy alloys in the composition range of 51< Cu <67, 5 < Hf < 40 and 5 < Ti <40 (at.%) are reported and discussed. It is found that increasing the Ti:Hf ratio results in a rapid decreasing of T g and T x . This behavior is related to the fact that the melting point and cohesive energy for Ti are substantially lower than for Hf. The solidus temperature T m , remains relatively constant on a wide range of compositions. The liquidus temperatures data suggest a ternary eutectic within the compositional field encompassed by the Cu55Hf20Ti25, Cu59Hf21Ti20, Cu60Hf20Ti20 and Cu55Hf21Ti24 alloys, with a liquidus temperature, T l , of ∼1170 K; this is supported by the DTA traces, which show a single melting peak. Based on the DTA analysis, the experimentally calculated liquidus projection for the ternary Cu-Hf-Ti alloy system is also reported.

In the framework of bioanalytics and multiple array detection, we developed a fully portable and low-cost detection system based on Localized Surface Plasmon Resonance (LSPR) in a transmission configuration (T-LSPR). The transmission approach is suitable to be scaled to small dimension systems and to enable high-density array measurements on the same platform. Our setup is made out of off-the-shelf components and consists of a set of discrete light sources and a couple of light-detectors which enable a differential measurement setup. An algorithm fits the measured data and extracts the information of the plasmon peak position in the spectrum.

The performance of our T-LSPR measurement system has been characterized on a set of Fluorinated Tin Oxide-coated glass slides covered with gold Nanoislands (NIs). The samples have been modified with a single-stranded DNA layer and a real-time DNA hybridization experiment has been performed. Here we demonstrate that the proposed T-LSPR device, based on the characterization of the plasmon peak with a differential approach, is able to monitor real-time DNA hybridization on surface, and to precisely measure the position of the peak with a standard deviation in wavelength of 0.2 nm.