Tin zinc oxide (SnZnO) thin film transistors (TFTs) with different component fraction fabricated by solution process were reported. Sn chloride and Zn acetate were used as precursor and the maximum annealing temperature was 500°C. The electrical characteristics of TFTs were acutely affected by the molar ratio between Sn and Zn in the lattice, and showed the highest mobility and on-to-off ratio of about 17 cm2/Vs and 2×106, respectively. The origins of the high performance were traced through both structural and electrical aspects. Sn was generally considered to offer carrier path by superposition of s orbital, but it was found that the increase of Sn fraction only below specific value in lattice contributed to increase mobility, which could be explained by the structural distortion and the defect generation. Zn atoms introduced in the lattice were necessary to control both mobility and carrier concentration. From these results, the solution-processed SnZnO TFT with high performance was suggested.

The impact of Nd2O3, MoO3 and RuO2 addition on the competition between the crystallization of apatite Ca2Nd8(SiO4)6O2 and powellite CaMoO4 phases which both may appear in High Level Waste nuclear glass (under certain specific conditions of cooling and glass composition) has been studied on a simplified composition belonging to the system SiO2-Na2O-CaO-Al2O3-B2O3. X-ray diffraction (at room temperature and high temperature) and scanning electron microscopy measurements have been performed on five glasses under two different thermal treatments. We show that RuO2 acts as a nucleating agent for apatite. Moreover, neodymium and molybdenum cations seem to be very close in the glassy network as Nd2O3 addition stops the phase separation of molybdates and inhibits the crystallization of CaMoO4. On the contrary, MoO3 seems to favor the crystallization of apatite. For several samples, the evolution of the distribution of Nd3+ cations after crystallization was followed by optical absorption spectroscopy.

Pulsed-laser-deposited ZnO thin films were exposed to a 1.5 MeV helium ion beam to study the changes in radiative and non-radiative recombination. We first measured photoluminescence (PL) spectra at 4.2 K excited with the 325 nm line of a HeCd laser. The as-deposited films showed a donor-bound exciton peak at 3.3567 eV attributed to Zn interstitials. After irradiation the donor-bound-exciton dominated PL spectra shifted to acceptor-bound behaviour with a signal at 3.3519 eV, tentatively attributed to Li or Na acceptors. In contrast to the approximately 30 % decrease of the PL signal near the band edge, we observed a strong concomitant enhancement of the green/orange PL band, located between 2.1 eV and 2.8 eV, by a factor of over 4. Candidates for those transitions are Li impurities and/or O vacancies. For comparison, the steady-state photocurrent decreased strongly in the irradiated region, which can also be attributed to increased non-radiative recombination through oxygen-related defects.

Silicon Carbide (SiC) Metal-Oxide-Semiconductor (MOS) capacitors, having different nitridation times, were characterized by means of Constant Capacitance Deep Level Transient Spectroscopy (CCDLTS). Electron emission was investigated with respect to the temperature dependence of emission rates and the amplitude of the signal as a function of the filling voltage. The comparison between the emission activation energies of the dominant CCDLTS peaks and the filling voltages, led to the conclusion that the dominant trapping behavior originates in the Silicon-dioxide (SiO2) layer. Moreover, a model of electron capture via tunneling can explain the dependence of the CCDLTS signal on increasing filling voltage.

Rapid development in the area of low-temperature fuel cells has led to increased attention on catalyst synthesis with cost effective and environmentally-benign technology (green chemistry). In this study, a highly dispersed palladium nanoparticle catalyst was successfully prepared on a bacterial cell support by a single-step, room-temperature microbial method without dispersing agents. The metal ion reducing bacterium Shewanella oneidensis were able to reduce palladium ions into insoluble palladium at room temperature when formate was provided as the electron donor. The prepared biomass-supported palladium nanoparticles were characterized for their catalytic activity as anodes in polymer electric membrane fuel cell for power production. The maximum power generation of the biomass-supported palladium catalyst was up to 90% of that of a commercial palladium catalyst.

In this presentation we will discuss polishing performance and related mechanistic aspects of several low solids, low or high pH slurries based on Lewis acids abrasives (TiO2, ZrO2, CeO2), activated by cationic homopolymers, and copolymers with acrylic functionality. In a typical example, a formulation containing 0.5% ZrO2 interacting with 75 ppm cationic copolymer, at pH = 4, resulted in a SiO2 removal rate increase of 34% and a nitride removal rate increase of 97%, as compared with the control lacking the cationic copolymer. We will provide a complex variety of analytical evidence and particle and wafers surface measurements (FT-IR, GPC, surface energy) in order to support our mechanistic hypotheses. We will show with this unique system that 1:1 selectivities of oxide and nitride can be achieved with high removal rates.

Photovoltaic performance of dye sensitized solar cell (DSSC) was enhanced by 19 and 69 % compared to untreated DSSC by treating the nanoporous titanium dioxide (TiO2) by ultra thin Aluminum oxide (Al2O3) and Hafnium oxide (HfO2) grown by atomic layer deposition method. Activation energy of dark current, obtained from the temperature dependent current-voltage (I-V-T), of the untreated DSSC was 1.03 eV on the other hand the DSSCs with Al2O3 and HfO2 surface treatment showed 1.27 and 1.31 eV respectively. A significant change in the activation energy of dark current, over 0.24 eV for Al2O3 treatment and 0.28 eV in case of HfO2 treatment, suggest that density and activity of surface states on nanoporous TiO2 was suppressed by ALD grown metal oxides to result improved photovoltaic performance. Further the enhanced DSSC performance was confirmed by external quantum efficiency measurement in the wavelength range of 350-750 nm.

The fabrication of Si nanocrystals (NCs) in multilayer structures based on HfO2 and alloys for memory applications is carried out using an innovative method, the ultra-low energy (1 keV) ion implantation followed by a post-implantation annealing. Si+ ions are implanted into SiO2 thin layers deposited on top of thin HfO2-based layers. After annealing at high temperature (1050°C), the implantation leads to the formation of a two dimensional array of Si NCs at a distance from the surface larger than expected, due to an anomalous oxidation of the implanted Si. Nevertheless, the best memory windows are obtained at lower thermal budget, when no nanocrystals are present in the layer. This suggests that electrical measurements should always be correlated to structural characterization in order to understand where charge storage occurs.

The time-temperature-transformation (TTT) curve for the δ → α′ isothermal martensitic transformation in a Pu-1.9 at. % Ga alloy exhibits an anomalous double-C curve. Recent work suggests that an ambient temperature conditioning treatment enables the lower-C curve. However, the mechanisms responsible for the double-C are still not fully understood. When the δ → α′ transformation is induced by pressure, an intermediate γ′ phase is observed in some alloys. It has been suggested that transformation at upper-C temperatures may proceed via this intermediate phase, while lower-C transformation progresses directly from δ to α′. To investigate the possibility of thermally induced transformation via the intermediate γ′ phase, in situ x-ray diffraction at the Advanced Photon Source was performed. Using transmission x-ray diffraction, the δ → α′ transformation was observed as a function of time and temperature in samples as thin as 30 μm. The intermediate γ′ phase was not observed at -120°C (upper-C curve) or -155 °C (lower-C curve). Results indicate that the bulk of the α′ phase forms relatively rapidly at -120 and -155 °C.

The evolution of pore and grain structure in a nuclear fuel environment is strongly influenced by the local temperature, and the temperature gradient. The evolution of pore and grain structure in an externally imposed temperature gradient is simulated for a hypothetical material using a Potts model approach that allows for porosity migration by mechanisms similar to surface, grain boundary and volume diffusion, as well as the interaction of migrating pores with stationary grain boundaries. First, the migration of a single pore in a single crystal in the presence of the temperature gradient is simulated. Next, the interaction of a pore moving in a temperature gradient with a grain boundary that is perpendicular to the pore migration direction is simulated in order to capture the force exerted by the pore on the grain boundary. The simulations reproduce the expected variation of pore velocity with pore size as well as the variation of the grain boundary force with pore size.

Phase-change kinetics, structure evolution and feasibility to phase-change memory (PCM) of Ag2In7Sb64Te27 (AIST) and its nanocomposite comprised of 85 wt.% AIST and 15 wt.% SiO2 were presented. In-situ heating x-ray diffraction (XRD) indicated nanocomposite transforms from amorphous to HCP structure during heating and incorporation of SiO2 increases the recrystallization temperature (Tx ) of samples (189°C for AIST and 223°C for nanocomposite). XRD and transmission electron microscopy (TEM) analyses both revealed the grain refinement in nanocomposite. Kissinger's analysis found the increase of activation energy (Ea ) of phase transition in nanocomposite, denoting the SiO2 embedment restrains the grain growth of AIST during recrystallization. Johnson-Mehl-Avrami (JMA) theory revealed the decrease of Avrami exponent (n), indicating that the phase transition is prone to be heterogeneous since the dispersed SiO2 particles may provide additional nucleation sites.

Static I–V measurement indicated that the switching threshold voltage (Vth ) of nanocomposite device (1.65 V) is higher than that of the AIST device (1.10 V). Increase of dynamic resistance in nanocomposite device leads to the reduction of writing current. I–V analysis also confirmed the retardation of recrystallization in AIST due to the incorporation of SiO2 and the rise of Ea is able to enhance the thermal stability of amorphous state in PCM devices.

In this work, mechanochemical activation was found to be an effective method to improve nitrogen (N)-doping efficiency and the photocatalytic H2 evolution rate of InNbO4. The effects of mechanochemical treating time on phase formation, surface area, crystallite size, optical property, N-doping efficiency, and photocatalytic activity of InNbO4 were investigated experimentally. The results indicated the decreasing of crystallite size was an important factor for the improvement of N-doping efficiency and photocatalytic activity.

We explored the effect of K and K-Na substitution for Pb atoms in the lattice of PbTe, in an effort to test a hypothesis for the development of a resonant state that may enhance the thermoelectric power. At 300K the data can adequately be explained by a combination of a single and two-band model for the valence band of PbTe depending on hole density that varies in the range 1-15 × 1019 cm-3. A change in scattering mechanism was observed in the temperature dependence of the electrical conductivity, σ, for samples concurrently doped with K and Na which results in significantly enhanced σ at elevated temperatures and hence power factors. Thermal conductivity data provide evidence of a strong interaction between the light- and the heavy-hole valence bands at least up to 500K. Figure of merits as high as 1.3 at 700K were measured as a result of the enhanced power factors.

3D interconnect wafer-to-wafer or die-to-wafer integration requires a wafer thinning operation to expose copper (Cu)-filled through-silicon vias (TSVs) from the backside of the wafer. The wafer thinning flow uses edge trim, backgrind, backpolish, and chemical mechanical polishing (CMP). This paper presents an overview of the wafer grinding process. We have demonstrated the capability to edge-trim and backgrind 300 mm TSV and non-TSV wafers down to 30 microns (μm) while bonded to a handle wafer. TSV wafers were further processed on a CMP tool to remove the last few microns of Si, exposing the Cu-filled TSVs. Metrology techniques were used to inspect and measure the wafer edge trim and final thinned wafer thickness. The quality of the thinned wafer was characterized by atomic force microscopy (AFM) to observe surface roughness and by transmission electron microscopy (TEM) to quantify crystalline damage below the surface of the thinned wafer. Further characterization included measuring wafer thickness, total thickness variation (TTV), bow, and warp. Exposed TSVs were characterized by laser microscope to measure the height of Cu protrusions. These critical elements of a manufacturing-worthy 300 mm wafer thinning process for 3D are discussed.

Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are considered key pathogens in periodontitis that is the principal cause of tooth loss in adults. The treatment of periodontal disease consists on the use of chemicals which can alter oral microbiota and have undesirable side-effects such as vomiting, diarrhea and tooth staining

At recent years, the use of natural sources like biomaterials such as biopolymers and plant extracts are enjoying great popularity. Chitosan and pullulan are polymers that have been proposed due to their favorable properties such as biocompatibility, biodegradability, adhesion ability and nontoxicity

The aim of this study was to develop films from chitosan and pullulan containing plant extracts as delivery system and determine the in vitro antibacterial activity against periodontopathogen microorganisms and their stability under different conditions of storage

In this work, the mechanical properties of cubic silicon carbide are explored through the analysis of the static and dynamic behavior of 3C-SiC cantilevers. The investigated structures were micro-machined using Inductively Coupled Plasma (ICP) etching of thin 3C-SiC films grown on silicon. The aim was to evaluate the influence of some basic parameters (film orientation, film thickness, defect density) on the mechanical properties of the material.

X-Ray Diffraction was used to evaluate the crystalline quality of the epilayers. Scanning Electron Microscopy observations of static cantilever deflection highlight the major difference between the stress states of (100) and (111) oriented layers for which the intrinsic stresses are of opposite signs. The cantilever deflection is highly dependent on the film thickness, as stated for (100) oriented epilayers. The lowest deflection is obtained for the thickest layer. The Young's modulus of 3C-SiC is calculated from the resonance frequency of clamped-free cantilevers, measured by laser Doppler vibrometry. The relatively low and orientation independent value of Young's modulus (~350GPa) found on the samples is probably associated with the high defect density usually observed in very thin 3C-SiC films grown on Si.

A high chromium ferritic Oxide Dispersion Strengthened steel was produced by mechanical alloying of Fe-18Cr-1W-0.3Ti-0.3Ni-0.15Si and 0.5% Y2O3 (wt.%) powders in industrial attritor, followed by hot extrusion at 1100°C. The material was characterized by Atom Probe Tomography on each step of manufacturing process: as-milled powder and in final hot extruded state. In addition, to get information on clustering kinetics the powder was also characterized after annealing at 850°C during 1 hour. Atom Probe Tomography revealed that the oxide dispersion strengthened steel Fe-18Cr contains nanometer scale yttrium- and oxygen-enriched nanoclusters in as-milled state. Their evolution is shown after subsequent annealing and hot extrusion. More well defined nanophases also enriched in Ti are observed. A mechanism of their formation is proposed. Mechanical alloying results in supersaturated solid solution with presence of small Y- and O-enriched clusters. Subsequent annealing stimulates incorporation of Ti to the nucleii that were previously formed during mechanical alloying.

Crystalline precipitates from molybdenum-containing nuclear waste glasses are complex, often containing multiple cations which confound routine structural techniques. A simplified mixed-alkali borosilicate model glass was found to have minor crystalline phases which could not be identified by x-ray diffraction. Multinuclear magnetic resonance (NMR) spectroscopy revealed sharp peaks characteristic of crystallinity superimposed on the broader glass signals, but were unattributable to any known molybdate phases. When a comprehensive range of cesium molybdates failed to reveal any matches with the observed 133Cs magic-angle spinning (MAS) NMR peaks in the composite glass/crystalline material, a series of mixed-alkali sodium-cesium molybdate phases was synthesized. 23Na, 133Cs and 95Mo MAS NMR revealed the formation of two mixed-cation molybdates which correlate with the observed NMR peaks for the phase-separated model glass. This work highlights the prominence of multiple crystalline phases in Mo-bearing nuclear waste glasses, and demonstrates the unique utility of solid-state NMR as a fingerprinting approach to identifying complex phases, especially where x-ray diffraction is limited by multiple phases, low concentrations or substitutionally disordered precipitates.

Heat dissipation in Silicon-On-Insulator (SOI) based microdevices is hindered in the silicon device layer by the low thermal conductivity of the neighboring oxide and reduced in-plane thermal conductivity in very thin layers. This work shows that the in-plane thermal conductivity of a 260 nm thick device layers in SOI substrates can be characterized by measuring the temperature distributions induced by AC joule heating through microfabricated heaters by a scanning thermoreflectance technique. These data were fitted to numerical solutions of the heat conduction equation calculated using COMSOL® Multiphysics modeling software, suggesting the in-plane thermal conductivity of the device layer is reduced to 90±10 W/(m.K), which is consistent with phonon boundary scattering theory predictions.

We have performed the finite element simulations to study the binding reaction kinetics of the analyte-ligand protein pairs, C-reactive protein (CRP) and anti-CRP, in a reaction chamber of a biosensor. For diffusion limited reactions, diffusion boundary layers often develop on the reaction surface, thus hindering the reaction. To enhance the efficiency of a biosensor, a non-uniform AC electric field is applied to induce the electrothermal force which stirs the flow field. Biosensors with different arrangements of the electrode pairs and the reaction surface are designed to study the effects of geometric configurations on the binding efficiency. The maximum initial slope of the binding curve can be 6.94 times of the field-free value in the association phase, under an AC field of 15 rms and an operating frequency of 100 kHz. With the electrothermal effect, it is possible to use a slower flow and save much sample consumption without sacrificing the performance of a biosensor. Several design factors not studied in our previous works such as the thermal boundary conditions are discussed.