Silicon germanium (SiGe) is considered to substitute silicon (Si) as channel material of p-type MOSFET in future CMOS generations due to its higher hole mobility. In this work we investigate SiGe channels with a germanium concentration of 23 at% and 30 at%, even though the mobility is expected to be higher with even more germanium in the alloy. Low pressure chemical vapor deposition was used for SiGe deposition. A state of the art CMOS process including high-k dielectric and metal gate electrode was applied for fabrication of sub 50 nm gate length devices. As expected from the SiGe channel conduction and valence band offset the threshold voltage of the devices is influenced. The gate stack was directly deposited onto the SiGe layer consisting of a chemically grown base oxide, hafnium-based dielectric and titanium nitride gate electrode. C-V and I-V measurements show comparable CET and leakage values for the high-k metal gate stack on Si and SiGe channels. The trap density at the channel dielectric interface was determined using the charge pumping technique. The device characteristics of n- and p-MOSFETs with SiGe channels are compared to conventional Si channel devices. Short channel mobility was extracted with the gM,LIN-Method.

Plasma spraying is a well-established method for depositing nanostructured ceramic coatings on structural components. Two different plasma spraying techniques - solution precursor plasma spray (SPPS) and suspension plasma spray (SPS) - have been used to produce MgO-50vol% ZrO2 composite coatings. The microstructural features of the coatings were characterized using Environmental Scanning Electron Microscopy (ESEM) and X-Ray Diffractometry (XRD). The micro hardness of the coatings was measured on cross-sectional samples. The coatings produced using the SPS process with ethanol-based suspensions at a high plasma torch power (45.5 kW) exhibited the densest microstructures with hardnesses as high as ∼1350 HV. However, the backscattered electron (BSE) ESEM characterization of these coatings revealed that the coatings obtained using the SPPS technique had superior chemical homogeneity over those obtained using the SPS technique.

Blood-cell-free serum is required for most clinical chemistry tests. At present bend micro channel and polymeric pillars are used in polymer based microfluidic devices (such as PMMA) for the blood filtration. In this study, we have fabricated carbon nanotube (CNT) pillars on silicon from 20-50 μm in diameter with ˜10 μm spacing and integrate them inside the microfluidic channel with a view of using these for blood plasma filtration from whole blood, with passive capillary flow. Our main objective is to design a novel sensor, comprising CNT arrays, to filter/control whole blood flow, with an integrated micro patterned gold electrode which will be sealed by bonding into microfluidics structures. We have characterized the microfluidic channel by measuring the meniscus movement profiles. Also gold inter-digitated electrodes (IDEs) were fabricated on glass and immobilized with an antibody. These IDEs were used as an impedance-based biosensor using label-free antigen – antibody interaction. At a fixed frequency, the IDEs gave a linear response across the range of concentrations of secondary antibodies investigated (0 to 500 μg/mL).

The porous structure of aluminum foams was quantitatively monitored in terms of pore density, pore area, and shape and size distribution using image analysis; then, related to density and expansion profiles by interrupted experiments. This practice offers important information in the control and reproducibility of foams. The aluminum foams were produced by the powder compact melting method at 800°C. The foamable precursors consisted in uniaxial cold pressed Al-TiH2 mixtures compacted at 387 MPa; the pressure applied and particle size distribution of the mixture originated preforms with 95.9% densification. This procedure eliminated the traditional hot-compaction step; besides, the amount of foaming agent was kept to a minimum of 0.5 wt.% TiH2. A volume expansion of 215 to 236% and densities from 0.7730 to 0.8206 g/cm3were obtained in a time window of 420 to 570 s. The calculated shape factors and Feret diameters defined how the roundness of pores varies with size all along the foaming process.

Technetium has a long half life of up to 2.13×105 years. It is separated from liquid waste streams with tetraphenylphosphonium bromide [1], which upon degradation releases Tc as the pertechnetate anion, TcO4 −. Pertechnetate is highly mobile in groundwater and it is therefore highly desirable to capture and immobilise this anion within a solid for interim and ultimately long term storage. Layered Double Hydroxide (LDH) materials are known to possess excellent anion sorption capabilities due to their structure which consists of ordered positively charged sheets intercalated with interchangeable hydrated anions. The composition can be tailored to produce suitable precursors for ceramic phases by varying the divalent and trivalent cations and the anions. LDHs with the general formula Ca1-x (Fe1-y, Aly)x (OH)2 (NO3)x . nH2O were produced by a co-precipitation method from a solution of mixed nitrates. Calcination leads to the formation of Brownmillerite Ca2(Al,Fe)2O5 like compounds for temperatures as low as 400°C, this is close to the lowest temperature at which Tc is known to volatilise (310.6 °C Tc2O7). It was shown that after calcining up to 600°C, the LDH structure is recovered in water allowing rapid ion capture to occur. This suggests that these materials have potential for both capture and as a storage medium for Tc.

Graphite is used as the neutron moderator and reflector in many nuclear reactors. Obsolete graphite nuclear reactors are put out of operation, leading to formation of a large quantity of radioactive graphite waste.

It is proposed that irradiated reactor graphite is processed by high-temperature chemical oxidation in salt melts with an oxidant, which is part of the salt melt, leading to formation of exhaust gases: gaseous compounds of carbon and oxygen (CO2 and CO).

This study deals with carbon oxidation and physical-chemical transformations of radioactive elements during the interaction between graphite waste of the atomic power industry and salt melts. The method of thermodynamic simulation is used. The carbon melt decreases the transfer of radionuclides to the gaseous phase as compared to incineration of graphite in the atmosphere.

The extracellular matrix plays a crucial role in defining the mechanical properties of connective tissues like cornea, heart, tendon, bone and cartilage among many others. The unique properties of these collagenous tissues arise because of both the hierarchal structure of collagens and the presence of negatively charged proteoglycans (PGs) which hold collagen fibers together. Here, in an effort to understand the mechanics of these structures, using the nonlinear Poison-Boltzmann (PB) equation, we study the electrostatic contribution to the elasticity of corneal stroma due to the presence of negatively charged PG glycosminoglycans (GAGs). Since collagens and GAGs have a regular hexagonal arrangement inside the corneal stroma, a triangular unit cell is chosen. The finite element method is used to solve the PB equation inside this domain and to obtain the electric potential and ionic distributions. Having the ion and potential distributions throughout the unit cell, the electrostatic free energy is computed and the tissue elasticity is calculated using the energy method. It is shown that as the ionic bath concentration increases; the electrostatic contribution to tissue elasticity is reduced.

The complex [Ir(ppy)2(dpbpy)][PF6] (Hppy = 2-phenylpyridine, dpbpy = 6,6'-diphenyl-2,2'-bipyridine) has been prepared and evaluated as an electroluminescent component for light-emitting electrochemical cells (LECs). The complex exhibits two intramolecular face-to-face π-stacking interactions and long-lived LECs have been constructed; the device characteristics are not significantly improved in comparison to analogous LECs with 6-phenyl-2,2'-bipyridine with only one π-stacking interaction.

Amorphous Si/SiOx multi-layered films and nanostructures were deposited on Si substrates by the glancing angle deposition technique using Ar ion beam sputtering of a Si sputter target in an intermittent oxygen atmosphere at room temperature. The chemical composition of the samples was characterized by time-of-flight secondary ion mass spectrometry, as well as - for quantifying these first results - by elastic recoil detection analysis using a 200 MeV Au ion beam. The latter method was found to lead to a significant alteration of the sample morphology, resulting in the formation of complex nanometric structures within the layer stacks. In order to investigate these swift heavy ion irradiation induced effects in more detail, a series of experiments was conducted to determine the dominating influences. For this purpose, specific glancing angle deposited multilayered films and nanostructures were irradiated to constant ion fluence with the same 200 MeV Au ion beam at different incidence angles. Scanning electron microscopy of the stacks before and after swift Au ion irradiation revealed considerable changes in film morphology and density as a function of the ion incidence angle, such as an increased porosity of the silicon layers, accompanied by a layer swelling. In contrast, the SiOx layers did not show such effects, but exhibited clearly visible swift heavy ion tracks. The observed effects became stronger with decreasing ion incidence angle.

We present the results of an electrical injection study of spin polarized electrons from ferromagnetic Fe contacts into electronic shells of self-assembled InAs quantum dots (QDs) incorporated in GaAs/AlGaAs spin LED structures. The circular polarization of the emitted light was measured as function of current and magnetic field. The polarization of the EL spectra exhibits strong maxima at energies that do not coincide with the electroluminescence (EL) intensity peaks. The magnetic field dependence of the polarization maxima is consistent with spin injection from the ferromagnetic Fe contacts. The experimental results are compared with calculated emission spectra from multi-exciton complexes (N = 2 and N = 6) as function of electron spin polarization. The energies of the EL features as well as their polarization characteristics are understood in terms of energy shifts due to exchange interactions between spin-down electrons occupying adjacent shells.

Cu2ZnSnS4 (CZTS) thin films were fabricated by using three RF co-sputtering continued with sulfurization method. The new type of thin film solar cells using CZTS as an absorber consists of buffer-layer and window-layer on CZTS films that were fabricated on a Mo-coated Soda Lime Glass (SLG) substrate. It was confirmed that CZTS solar cells with high conversion efficiency existed in a relatively narrow composition region. In this paper, the fabrication method of CZTS-based thin film solar cells in our laboratory was stated briefly and the influence of the composition ratio on the photovoltaic properties were presented. Furthermore, the properties of a genuine non-toxic solar cell using a Cd-free buffer-layer were introduced.

Nanoparticles Fe (x wt. %)-doped Zn-TiO2 rutile powders, with x between 0 an 10 wt. %, were prepared using a solution chemistry route based on the wet-gel stirring method. Using the TEM images we found that the powder samples exhibit nanorods and nanosheets with nanorods oriented in different directions and accompanied by an amorphous Zn on the surface. The average length of these nanorods is about 60 nm and they have an average diameter of 7 nm. The x-ray diffraction patterns revealed the formation of the nanocrystalline particles with the rutile phase, which is characterized by the (101) diffraction peak. The magnetic properties of the samples were studied using a vibrating sample magnetometer (VSM) in magnetic filed up to 13.5 kOe and in the temperature range of 100 K to 300 K. We found that the magnetization of the samples does not saturate in the maximum available field. The magnetization (M) at an applied magnetic field of 13.5 kOe is found to increase with increasing the Fe percentage at room temperature and at 100 K. TEM measurements and atomic-force microscopy (AFM) were used to image the samples.

This work is aimed at the interactions between hydrogen atoms contained in high concentrations in metal lattices. Effects of metals on hydrogen interactions are surveyed by carrying out molecular dynamics (MD) simulations on hydrogen fluids containing palladium atoms, from a viewpoint in contrast to previous simulations on low concentrations of hydrogen in metal lattices. Some results of these simulations reveal the dissociation of H2 molecules to H atoms due to the presence of Pd atoms under densification, and therefore imply the change of attractive H-H interactions in H2 molecules to repulsive interactions of H atoms in Pd lattices. These repulsive interactions are consistent with an empirical “2-Å rule” of hydrogen atoms in metal lattices, and impose limits on hydrogen-storage capacities of metals.

Doping polymers with inorganic nanomaterials to form hybrid nanocomposites is an attractive approach to develop new lightweight optoelectronic materials with unique or improved properties. In this work, poly(3-hexylthiophene) (P3HT) Schottky diodes, doped with ZnO nanowires at different P3HT-to-ZnO concentrations, were studied. Device fabrication was carried out by drop casting the nanocomposite on a Pt electrode followed by thermal evaporation of an Al top electrode. ZnO nanowires were prepared via a physical vapor method with Zn as a source. The nanowires were dispersed in chlorobenzene, then the P3HT powder was added. Properties of the diodes were investigated using capacitance-voltage and current-voltage measurements. In addition, electrical resistance of the nanocomposite films was also investigated using a two-point probe measurement with Pt as Ohmic contacts. Results showed that ZnO nanowire doping decreases the built in potential of the diode and the electrical resistance of the nanocomposite film.

A theoretical study of resolution in nanoimprint lithography (NIL) has been carried out using molecular dynamics (MD) simulation. We have performed a MD simulation for glass NIL, monitored the friction force during entire NIL process and evaluated the deformed shapes of glass patterns after the mold releasing. The resolution in NIL is governed by the maximum tensile stress acting on the glass, which is induced by the friction force during the mold releasing. Based on the distribution of average number density of atoms in the molded glass, the ultimate resolution in the glass NIL has been proved to be 0.4 nm.

In chemical-mechanical polishing (CMP) the material removal efficiency (MRE) can be defined as the fraction of the total pressure distributed on the abrasives, and it depends on the interplay between the direct contact of the pad-to-wafer, and the contact of the abrasives with the wafer. The MRE can be increased by minimizing pad-wafer direct contact, as this is not likely to help material removal, significantly. The objective of this work is to investigate parameters that control MRE. This may be especially important for low-pressure CMP used in the polishing of (ultra-low-k) ULK dielectric materials. The optimization of CMP parameters to maximize the MRE is described by modeling the contact interactions between pad, abrasives and wafer. A relationship for optimal abrasive concentration is presented for the external load values that mark the transition from pure pad-wafer-abrasive contact to mixed contact (combination of pad-wafer-abrasive and pad-wafer contacts) and for given pad porosity and pad surface parameters.

ZnO has recently attracted a great deal of attention as a material for transparent contacts in light emitters and adsorbers. ZnO films heavily doped with Ga (carrier concentration in the range of 1020 - 1021 cm-3) were grown on a-plane sapphire substrates by RF plasma-assisted molecular beam epitaxy. Oxygen pressure during growth (i.e. metal (Zn+Ga)–to–oxygen ratio) was found to have a crucial effect on structural, electrical, and optical properties of the ZnO:Ga films. As-grown layers prepared under metal-rich conditions exhibited resistivities below 3×10-4 Ω-cm and an optical transparency exceeding 90% in the visible spectral range. In contrast, the films grown under the oxygen-rich conditions required thermal activation and showed inferior structural, electrical, and optical characteristics even after annealing.

Negative refractive index materials tuned at n = -1 are believed to realize perfect lensing of real and evanescent modes. Metamaterials are the natural candidates to realize negative refractive index by the inversion of the effective dielectric permittiviy and magnetic permeability. The effect of the density on the tuning in the proximity of n = -1 is studied in order to find viable solutions to the issue of discretization of the lattice which correspondingly produces steps in the electromagnetic parameters of metamaterials. We study the microwave frequency negative refractive index of a metamaterial as a function of the density of the lattice period. The negative refractive index is realized by means of a waveguide filled with a split ring resonator lattice, exploited below the cut off frequency of the waveguide. We discuss the pass-band behaviour and the collective effects on the negative refractive index.

This talk will reflect on the challenges of designing educational opportunities that broaden diversity in the ranks of future scientists and engineers. The speaker, who is Education Director at the California Nanosystems Institute (CNSI) at the University of California, Santa Barbara, will report on the design and evaluation of a program that integrates academic, career and social components to engage a community of undergraduates, graduate mentors and research faculty at UCSB. The program builds on key practices such as academic mentorship, community networking and early undergraduate research. Evaluation of this program, Expanding Pathways to Science, Engineering and Mathematics (EPSEM) indicates that it has been successful in recruiting and retaining students from under-represented (URM) groups into science, technology, engineering and math disciplines (STEM disciplines).

By using a multi-color, multi-modal imaging platform, we look into the effects of exciton-plasmon coupling on optical properties of a semiconductor quantum dot (QD) that is coupled to a nearby gold NPs (AuNPs). By exciting this coupled material with laser excitation energies that are either strongly or weakly resonating with the plasmon resonance of the AuNP, the effects of plasmon-exciton coupling was studied in detail by analyzing the changes in the photoluminescence signal, the photoluminescence lifetime, and the blinking pattern of the QD.