We demonstrate the superior inductive properties of coiled carbon nanotubes (CCNTs) through numerical computation and analytical modeling, for the next generation of nanoscale, on-chip inductors. Taking advantage of the kinetic inductance (L k ), particularly evident at the nanoscale we find that the inductance can be increased by three orders of magnitude through changing the tube radius as well as the coil radius while the device footprint of the CCNTs can be reduced by 60%. By varying the geometric parameters of the coiled structure, the external magnetic inductance (L M,ext ) can be as high as 20% of the L k . We also report that the self resonant frequency (f SR ) of CCNTs can be as much of the order of THz whereas the f SR of conventional copper(Cu) spiral inductors are limited to around 40GHz. Moreover when the material volume is considered, CCNTs have the potential to achieve Quality Factor (Q) eight times as Cu and when the footprint volume is considered Q can be twice as Cu All these promising properties of CCNTs make them a potential candidate for the entire frequency spectrum.

Carbon/carbon composites (C/C composites) possess superior characteristics of low density, high strength, extremely low coefficient of thermal expansion, high fatigue resistance. In carbonization process, the high temperature pyrolysis made of carbon, hydrogen, oxygen and other elements, results in a lot of voids and cavities generated in the interior of C/C composites. Therefore, the C/C composites are densified to fill the void by using repeated impregnation. But densification is a time-wasting and complex process, which increases production costs in the manufacturing process.

In this study, the Multi-Wall Carbon Nanotubes (MWNTs) were adopted as reinforcement material for C/C composites to reduce the existence of voids or cavities and enhance the mechanical properties of C/C composites under environment aging effects. Three different temperature with high moisture conditions are used to be tested, including high temperature (150°C/ 90%RH), room temperature (25°C/90%RH), and low temperature (-15°C/90%RH) to analyze the mechanical properties of C/C composites, such as flexural and Interlaminar Shear Strength (ILSS).

We used sporopollenin prepared from Lycopodium Clavatum to encapsulate living yeast cells as a model for probiotics. The microencapsulation of cells was achieved by using the trilite scars of the sporopollenin microcapsules which can open up by compressing the sporopollenin into a pellet. Such compressed pellets were exposed to an aqueous suspension of yeast cells in the presence of a biocompatible surface active agent which allowed living cells to be loaded inside the sporopollenin particles by the influx of liquid to the sporopollenin interior as the deformed microcapsules re-inflated to their original state. We demonstrated that the cells viability and biological activity is preserved after the microencapsulation in the sporopollenin. Such microencapsulation technology could find application in preserving cells from mechanical stress and aggressive environments which can be used in protection of probiotics in food formulations.

In situ imaging using (scanning) transmission electron microscopy has proven to be an extremely important and powerful cross-disciplinary scientific technique. In particular nanotechnology and materials sciences have special interest in assembly and disintegration processes, in growth and shape-tuning of (nano)-particles, and, furthermore in mechanistic studies of chemical reactions underlying these processes. However, limitations for in liquid and in situ imaging using electron microscopy arise from the stringent experimental conditions required with respect to electron scattering.

Here, we present a nanofluidic sample cell allowing for controlled fluidic conditions which preserve the highest possible spatial resolution for in-liquid electron microscopy. The nanocell allows for liquid flow with a flow control mechanism operated external to the microscope column enabling on-the-fly sample exchange within the imaging area. A well-defined flow path allows us to direct the motion of gold nanorods through fluid flow. Further a particle’s Brownian motion becomes evident once the external flow is terminated. In addition to quantitatively showing the resolution capabilities of our nanofluidic design, we show preliminary results of in situ imaging of gold nanorods and unstained amyloid fibrils to emphasize the significance of this imaging modality for both material sciences and biology.

The efficacy of vertically aligned defect engineered multi-walled carbon nanotube (MWCNT) arrays as electrochemical double layer capacitors (EDLCs) was investigated using standard electrochemical techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). We report a ∼ 200% improvement in specific double layer capacitance of MWCNT arrays by extrinsically introducing defects using argon plasma irradiation. The capacitance-voltage characteristics of argon irradiated MWCNTs provide insights into the nature of the defects and their influence on the specific capacitance (capacitance/area).

The general public is typically positive towards ‘Nano’, but often have limited and anecdotal information from which to draw informed conclusions. We present lessons learned from a new demonstration for 1-on-1 and small group science expo table use that appears to captivate and lead to active learning for ages seven to adult. ‘Making Nanoparticles with Ouzo’ covers: 1. issues in measuring and seeing small particles; 2. light as having wave properties with wavelengths in the nm range; 3. using green (510 nm) and red (650 nm) laser pointers as ‘rulers’; 4. using the liqueur Ouzo (a blend of water, alcohol and water insoluble anethole oil) to illustrate and ‘illuminate’ nanoparticles invisible to the naked eye; 5. demonstrating that the anethole particles do not initially scatter laser light, but do as water is added and particle sizes increase; 6. allowing a visitor to ‘make nanoparticles’ by warming up a cold dispersion of cloudy anethole particles (micron size) in warm water until they vanish.

Although a lot of information is presented, a surprising amount of it seems to stick, if it is presented and built in story form from widely appreciated concepts, with samples and props people can see and hold, and with a few diagrams and written descriptions.

The synthesis of hierarchically assembled Al-doped ZnO layers by Pulsed Laser Deposition (PLD) at room temperature was investigated. PLD was performed in a background pressure of 100 Pa O2 to deposit clusters in a low energy regime and obtain nano- and mesostructures resulting from a hierarchical assembly of nanoclusters. We here analyzed the effects of varying the gas flow rate on mesoscale morphology, mass density and optical properties. The variation of the target-to-substrate distance was also investigated, identifying its effects on mass density and film morphology. The optimization of optical properties in terms of transparency and light scattering capability is of potential interest for photovoltaic applications.

The symmetry properties of many inorganic two-dimensional monolayer crystals make them piezoelectric, whereas their three-dimensional parent crystals are not. The emergence of piezoelectricity in the single-layer limit points toward intriguing electromechanical effects and applications in the single- or few-layer regime. We use density functional theory to calculate the piezoelectric coefficients of BN, MoS2, MoSe2, MoTe2, WS2, WSe2 and WTe2. These coefficients are found to be comparable to, and in some cases greater than those of commonly used wurtzite piezoelectrics. The centrosymmetry of a BN bilayer prevents a piezoelectric effect for this structure. However, by developing an elastic model, we find that the bilayer exhibits an unusual electromechanical coupling to the curvature, similar to that of a bimorph. A BN bilayer is found to amplify the constituent monolayers’ in-plane piezoelectric displacements by factors on the order of 103-104 into out-of plane deflections.

An effective n-type doping of ZnO using Cl was demonstrated in thin films electrochemically synthetized by adding different amounts of chlorine ions in the starting electrolyte. The ratio between chlorine and zinc cations was varied between 0 and 2 while the zinc concentration in the solution was kept constant. When the concentration of chloride in the bath increases an effective n-type doping of ZnO films takes place. n-type doping is evidenced by the rise of donors concentration, obtained from Mott-Schottky measurements, as well as from the blue shift observed in the optical gap owing to the Burstein-Moss effect.

Mesoporous carbon aerogel has been impregnated with iron (10 and 15 wt. %) as a catalyst for graphitization by wet incipient method. The iron modified and non-modified carbon aerogels were heat treated at 900°C, 1200°C, and 1400°C in argon. The crystal structure, morphology, and electro catalytic activity of the resulting nano-composites have been studied. It was found that, the degree of graphitization was proportional to the concentration of Iron phase and the ratio of iron to iron nitride phase in the heat-treated samples. In carbon aerogel sample sintered at 1200°C with 15 wt. % of iron phase, mesoporosity in the range of 3-4 nm and microporosity (< 2nm) was significantly improved by graphitization without affecting the Carbon Aerogels mesoporosity in 10-30 nm range. In this case of 15 wt. % iron doped samples, HRTEM analysis confirms the presence of uniformly distributed ∼43.5nm iron nanoparticles surrounded by graphene layers. Correspondingly, improved graphitization and presence of iron nitride resulted in 3.65 electron assisted oxygen reduction reaction.

The ability to efficiently harvest heat as a source of sustainable energy would make a significant contribution to reducing our current reliance on fossil fuels. Waste heat sources, such as those produced in industrial processes or through geothermal activity, are extensive, often continuous, and at present severely underutilised. Thermoelectrochemical cells offer an alternative design to the traditional semiconductor-based thermoelectric devices and offer thepromise of continuous and cheap operation at moderate temperatures, low maintenance and with no carbon emissions. They utilise two electrodes, held at different temperatures, separated by an electrolyte containing a redox couple. It is the temperature dependence of the electrochemical redox potential that generates the potential difference across the device as a result of the appliedtemperature difference. The magnitude of this redox potential temperature dependence is given by the Seebeck coefficient, Se. Until recently, research into thermoelectrochemical cells had primarily focused on aqueous media, predominantly with the Fe(CN)63-/4- redox couple.[1] However, the good thermal and electrochemical stability, non-volatility and non-flammability ofmany ionic liquids make them promising alternative electrolytes for these devices. The use of ionic liquid (IL) electrolytes offers potential advantages that include increased thermoelectrochemical device efficiencies and lifetimes and the ability to utilise low temperature (often “waste”) heat sources in the 100 – 200 °C temperature range.[2] Here we discuss our research into the use of the Fe(CN)63-/4- redox couple in protic IL electrolytes, with different amounts of added water, in a thermoelectrochemical device with platinum and single walled carbon nanotube (SWNT) electrodes.

In this study, in order to investigate biocompatibility of nitrogen-doped hydrogenated amorphous carbon (a-C:H:N) film coating segmented polyurethane (SPU) scaffold fiber sheet (a-C:H:N-Scaffold) in in-vitro test, mouse fibroblasts (NIH 3T3) cells were grown on the a-C:H:N-Scaffold. The cell behavior was monitored by time-lapse imaging system. Additionally, the a-C:H:N-Scaffold was implanted at partial aorta descendens of a goat for 35 days. The surface morphology, composition, and wettability of the a-C:H:N-scaffold was estimated by Scanning Electron Microscope (SEM), X-ray photoelectron spectrometer (XPS), and contact angle measurement. In in-vitro test, it was observed that a-C:H:N film coating had a facilitatory effect on cell motility and cell growth. In in-vivo test, it was observed that the a-C:H:N-Scaffold surface was uniformly covered by neointima. The a-C:H:N-Scaffold surface had no thrombus formation as an inflammatory reaction and it was shown that the a-C:H:N film coating had a good blood compatibility. These results suggest that a-C:H:N film coating has good cytocompatibility and blood compatibility and it is a promising approach for improvement of biocompatibility of biomaterial surfaces.

Light-emitting electrochemical cells (LECs) are one of the simplest electroluminescent devices. The possibility to be processed from solution and to operate with air-stable materials makes them an attractive alternative to organic light emitting diodes (OLEDs). Still their efficiencies are below those obtained in OLEDs. Additionally the best efficiencies were reported at low luminances and sustained for a short period of time. Here we show that for a LEC employing an orange-emitting charged iridium complex that is driven using a pulsed driving scheme high efficiencies of up to 20.5 cd A-1 can be obtained at high luminance and sustained over the device lifetime. It is also shown that the efficiency depends strongly on the current density applied.

Highly transparent conductive Ga-doped ZnO (GZO) films are one of the promising transparent conductive oxide (TCO) films for use in electrodes of flat display panels and window layers of thin film solar cells. For the ZnO-based TCO films, the stability to damp-heat environment is a crucial issue for practical applications. We will report moisture resistant GZO codoped with indium films (GZO:In) on the basis of analysis of data obtained a damp-heat test for solar cells (85°C and 85% relative humidity for 1000 hours).

We used ZnO sintered targets with contents of 3 wt% Ga2O3 and 0.25 wt% In2O3 to grow GZO:In films in ion plating with direct current arc-discharge system. GZO:In films with different thicknesses (0.1-1 μm) were deposited on glass substrates at 200°C under the O2 flow rate of 15 sccm. As the film thickness increased from 0.1 to 1 μm, the resistivity and sheet resistance decreased from 4.3 μΩm to 2.6 μΩm and from 42.7 Ω/Sq. to 2.6 Ω/Sq., respectively. And the average optical transmittance (T av ) in the range from 0.4 to 1 μm decreased from ∼ 86% to ∼ 75%. The GZO:In film with a thickness of ∼300 nm had a low sheet resistance of 10.5 Ω/Sq. and a T av of 82.5%. After 1000 hours damp-heat (DH) test under 85°C and 85% relative humidity, the relative change of sheet resistance is 3.4% with a Hall mobility of 26.4 cm2/V.s and a T av of 82.7% after test. The film thicker than 300 nm has a sheet resistance lower than 10 Ω/Sq. and a relative change of resistance of ∼3% after DH test.

We present a practical technique for fabricating silicon nanowire bridges on pre-patterned Si electrodes arrays. Silicon nanowires, catalyzed by gold nanoparticles, were grown on silicon electrodes from HF treated Au colloid as well as on electrodes treated with poly-L-lysine. Negligible growth was observed on untreated substrates due to poor adhesion of gold nanoparticles to the hydrogen terminated Si surface. In contrast, the treatments significantly increased occurrence of silicon nanowire bridges, which can be attributed to improved deposition of gold nanoparticles on the surface. Deposition time and concentrations of colloids also affected the occurrence of SiNW bridges. These results indicate that our techniqute for fabricating nanowire bridge arrays will be useful for large-area nanowire applications.

Formation of domain structures in two-step phase separation in Fe-based Fe-Ni-Al alloys are investigated by applying a time-dependent Ginzburg-Landau (TDGL) model. The present authors recently developed a TDGL formulation for ordering processes of B2 and D03 in binary alloys, taking into account the symmetrical relationships between these ordered phases. In this formulation, multiple types of variants of the structures are represented by three order parameters which can be measured independently through crystal structure factors. Mean-field free energies are defined in a form of Landau type expansion with the order parameters and a composition parameter. Interfacial energies due to local variations of degrees of order and composition are given in a gradient square approximation. Kinetic equations for time-evolution of the order parameters and the composition one are derived from the Ginzburg-Landau type potential consisting of the mean-field free energies and the interfacial energy terms. On the other hand, coauthors have investigated domain structures in two-step phase separation of Fe-based Fe-Ni-Al alloys. The evolution of three-dimensional domain structures and composition profiles has been analyzed by electron tomography imaging and energy-dispersive X-ray spectroscopy. In this work the authors performed three-dimensional numerical simulations assuming the thermal processing. The results of the simulations well reproduced the characteristics of the micro-structures obtained from the observations.

Cadmium sulfide nanoparticles were synthesized by a microwave-assisted route in aqueous dispersion. The cadmium sulfide nanoparticles showed an average diameter around 5 nm and a cubic phase corresponding to hawleyite. The aqueous dispersions of the nanoparticles were characterized by UV-Vis spectroscopy, luminescence analysis, transmission electron microscopy and X-ray diffraction. The addition of sodium hydroxide solutions at different concentrations causes a red-shift in the wavelength of the first excitonic absorption peak of the cadmium sulfide nanoparticles, indicating a reduction of the band gap energy. Besides, the intensity of the luminescence of the nanoparticle dispersions was increased. However, there is a threshold concentration of the hydroxide ion above which the precipitation of the cadmium sulfide nanoparticles occurs.

NaF precursor layers used for providing Na to Cu(In,Ga)Se2 (CIGS) grown on Na-free substrates have been studied. The NaF layers were deposited on top of the Mo back contact prior to the CIGS co-evaporation process. The co-evaporation process was interrupted after the preheating steps, and after part of the CIGS layer was grown. Completed samples were also studied. After the preheating, the NaF layers were analyzed with X-ray Photoelectron Spectroscopy and after growing part and all of the CIGS film, the Mo/NaF/CIGS stack was characterized using transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS). The NaF layers were found to be stable in thickness and composition during the pre-heating in selenium containing atmosphere before the CIGS process. The TEM analyses on the partly grown samples show a layer at the CIGS/Mo interface, which we interpret as a partly consumed NaF layer. This is corroborated by the SIMS analysis. In finalized samples the results are less clear, but TEM images show an increased porosity at the position of the NaF layer.

High integrity SiO2/Al2O3 gate stack has been demonstrated for GaN metal-oxide-semiconductor (MOS) transistors. The SiO2 film formed on GaN by the microwave-excited plasma enhanced chemical vapor deposition (MW-PECVD) exhibits good properties compared that by the LP (Low Pressure)-CVD. Then, by incorporating the advantages of both of SiO2 with a high insulating and Al2O3 with good interface characteristics, the SiO2/Al2O3 gate stack structure has been employed in GaN MOS devices. The structure shows a low interface state density between gate insulator and GaN, a high breakdown field, and a large charge-to-breakdown by applying 3-nm Al2O3. The SiO2/Al2O3 gate stack has also been applied to AlGaN/GaN hybrid MOS heterojunction field-effect transistor (HFET) and the HFET shows excellent properties with the threshold voltage of 4.2 V and the maximum field-effect mobility of 192 cm2/Vs.