The work function of the indium tin oxide electrode (ITO) modified by a self-assembled monolayer (SAM), which is used as an electrode in organic electroluminescent (EL) devices, was investigated in this study. It is revealed that chemical modification of ITO with p-substituted with different terminal groups (NH2−, Cl−, and CF3−) benzoic acids as a SAMs material with carboxyl binding group is caused to increase the work function of the ITO electrode. Through a self-assembly process, the transmittance of the ITO with a SAM was not changed. The work function change of ITO with various SAM was measured by using cyclic voltammetry. Characteristics of EL devices were increased because the energy barrier was decreased in an interface between the ITO and an organic layer in the EL devices. The correlation of the work function change and the performance of the chemically modified EL devices was estimated.

The Single Solid Source precursor Cadmium Acetylacetonate, Cd[C5H7O2]2 was prepared and Cadmium Oxide thin films were deposited on Sodalime glass substrate using Metal Organic Chemical Vapour Deposition (MOCVD) technique at deposition temperature of 420 oC The films were characterized using Scanning Electron Microscopy (SEM) with Energy Dispersive XRay (EDX) facility attached to it, X-Ray Diffractometry (XRD) and UV-visible spectrometry. SEM micrographs showed the formation of textured surface with identifiable cubic and hexagonal structures, having average grain size greater than 1 μm. XRD studies indicated the formation of polycrystalline cubic CdO phase with preferred orientation in (111) plane. A direct optical band gap of 2.10 eV was obtained from the analysis of the UV-visible spectrum with an enhanced light absorption in 750 – 1000 nm spectrum range. This enhancement is as a result of light trapping by the textured crystalline structure.

A metal-semiconductor contact with a n-type δ-doped quantum well of impurities (metal/δ-doped GaAs) was studied numerically to extract electronic properties such as energy levels and the corresponding wave functions of each level as well as the differential capacitance for the structure. In this work we reported these properties as a function of the hydrostatic pressure (p). We used the effective mass approximation for the calculation of the electronic structure and consider the hydrostatic pressure effects on the basic semiconductor parameters as is the effective mass for the conduction electrons and the static dielectric constant, finally we also take into account an experimental expression that dependency of the Schottky barrier height as a function of this external factor, at least for values between 0 and 6 kar. We showed that the linear behavior for C −2, obtained by pervious works, is switched over a parabolic-like curve due to the δ-doped two-dimensional impurities density.

After the Fukushima Dai-ichi nuclear accident, Japan Atomic Energy Agency (JAEA)was chosen by the Government to conduct decontamination pilotprojects at selected sitesin the contaminated area of Fukushima. Despite tight boundary conditions in terms of timescale and resources, the projectsprovide a good basis for developing recommendations on how to assure clean-up efficiency and worker safety and reduce time, cost, subsequent waste management and environmental impact. The results of the project can be summarised in terms of site characterisation and data interpretation, clean-up and waste minimisation and storage.

We have modified Sb2Te3 thin film thermoelectric materials by scanning a femtosecond laser across the film surface to create track-like nanostructures. These nanotracks have widths of 50-80 nm and a periodicity of ∼ 130 nm. We show that the nanotrack morphology is highly dependent on laser fluence and scan speed. Moreover, we performed transient thermoreflectance measurements on a laser-irradiated film and found a thermal conductivity reduction of 4.5% in the nanostructured regions compared to that of the unmodified regions. These results suggest the potential use of femtosecond pulsed lasers to create nanostructured thermoelectric materials with improved performance.

Uranium dioxide is the most common fuel used in commercial light water nuclear reactors. The fission of the fuel generates fission products (FPs) and minor actinides (MAs), which affects the thermo-physical properties of the fuel. The understanding of the physical and chemical properties of the FPs and MAs is still limited. In this study we have used atomic level simulations to estimate the effect of Ce4+ and Th4+ ions in urania matrix. Our results show that the structural variation depends on the elastic effect, which is guided by the ionic radius of the substituted ion. Ce4+ (ionic radius 0.97 Å) reduces the overall lattice parameter, while Th4+ (ionic radius 1.05 Å) increases the overall lattice parameter of the urania matrix (U4+ ionic radius 1.00 Å). In addition bulk modulus of the U1-xCexO2 system does not change with substitution while the modulus of U1-xThxO2 reduces with an increase in Th4+ ion concentration. This observation is in accordance with Vegard’s law prediction based on the modulus values of bulk UO2, CeO2 and ThO2 systems.

We report apparent robust doping of ZnO and MgxZn1-xO (x ∼20%) nanoparticle films by annealing in hydrogen gas. The annealing was done at sequentially higher temperatures from about 20 °C to 140 °C. The effect of the annealing was determined by comparing current-voltage measurements of the samples at room-temperature and in vacuum after each annealing cycle.The nanoparticles were grown using an aqueous solution and heating process that created thinfilms of ZnO or MgZnO nanoparticles with diameters of about 30 nm. When exposed to hydrogen gas at room-temperature or after annealing at temperatures up to about 100 °C, no measureable changes to the room-temperature vacuum conductivity of the films was observed. However, when the samples were annealed at temperatures above 100 °C, an appreciable robust increase in the room-temperature conductance in vacuum occurred. Annealing at the maximum temperature (∼135-140 °C) resulted in about a factor of about twenty increase in the conductivity. Furthermore, the ratio of the conductance of the ZnO and MgZnO nanoparticle films while being annealed to their conductance at room-temperature were found to increase and then decrease for increasing annealing temperatures. Maximum changes of about five-fold and seven-fold for the MgZnO and ZnO samples, respectively, were found to occur at temperatures just below the annealing temperature threshold for the onset of the robust hydrogen gas doping. Comparisons of these results to other work on bulk ZnO and MgZnO films and reasons for this behavior will be discussed.

Solid oxide fuel cells (SOFCs) have many advantages when compared to other fuel cell technologies, particularly for distributed stationary applications. As a consequence they are becoming ever more economically competitive with incumbent energy solutions. However, as with all technologies, improvements in durability, efficiency and cost is required before they become feasible alternatives. Such improvements are enabled through improved understanding of the critical material interactions occurring during operation. Raman spectroscopy is a noninvasive and non-destructive optical characterization tool which is ideally suited to the study of these critical chemical processes occurring within operational SOFCs. In this paper we will discuss advantages of using Raman characterization for understanding these important chemical processes occurring within SOFCs. We will present the specific examples of the type of measurement possible and discuss the direction of future research.

This work estimate the growth kinetics of Fe2B coatings created on surface nodular cast iron ASTM A-536 class 80-56-06. The Fe2B coatings were formed by power packaging boriding process, considering three temperatures and exposure times different treatment. The hard coatings were evaluated through X-ray diffraction (XRD) and scanning electron microscopy (SEM). The model of diffusion employs the mass balance equation at the (Fe2B/substrate) interface to evaluate the boron diffusion coefficient in the Fe2B coating DFe2B , an expression of the parabolic growth constant, the instantaneous velocity of the Fe2B/substrate interface, and the weight gain in the boriding sample were establish as a function of the parameter ε(T) and η(T), dependents of boriding process in function of the temperature related and the time of boriding t 0 (T), respectively in the Fe2B coating. Model validation was extended considering the treatment of 1273 and 1123 K for 10 h respectively, obtaining a good correlation with experimental data.

The ability to design a diagnostics platform that can achieve cellular level as well as molecular level classification of targeted biomarkers may be critical toward understanding the fundamental basis of disease initiation and proliferation in breast cancer. In this context, we have looked at breast cancer diagnostics and present the design of a biomedical microdevice for evaluating and classifying cellular samples based on their risk towards metastasis. Primary breast cancer tumors have been shown to contain heterogeneous populations of neoplastic cells. Recent studies have demonstrated that subpopulations of these cells can cooperate in the initiation of collective invasion and metastasis. The role of the sensor we present is to identify the type of cells as non-invasive/”follower” cells that do not result in metastasis or invasive “leader” cells that are thought to be responsible for metastasis, from breast cancer cell lysate samples, thus enabling more selective classification of samples, with the eventual goal of early diagnosis. The device is an electrical immunoassay that incorporates the PDGF- receptor to screen the cell lysate samples for the PGDF binding protein that is preferentially expressed in the invasive, “leader” cells. The sensor comprises of alumina nanochannel arrays integrated on to a microelectronic platform operating on the principle of electrochemical impedance spectroscopy to quantify the PGDF protein from the cell lysates.

Morphologies of silicon nanowires grown by plasma-assisted metalorganic chemical vapor deposition were studied in the presence of various dopant precursors. The varied precursors affected the axial and radial growth rates over orders of magnitude where triethylborane showed the strongest enhancements for both axial and radial growth, and triethylarsenic and triethylantimony retarded axial growth. Native oxide thickness is also shown to depend strongly on doping condition resulting in increased oxide thicknesses for increased carrier concentration, using shifts in the measured binding energy of the silicon 2p3/2 state as a proxy for carrier concentration.

Recently, bimetallic nanostructures and nanoalloys have received special interest due to their promising chemical and physical properties. Specifically, Cu-Ni nanoparticles have been investigated for biomedical and catalytic applications. This work reports the synthesis of alloys and bimetallic nanoparticles of CuxNi100-x (x = 20, 40, 50, 60 and 80) by sol-gel method, and their morphological, structural and magnetic characterization. A precursor material was prepared using a standard Pechini method and then CuNi nanoparticles were obtained by calcination treatments of the precursor in H2/N2atmosphere at 600 and 700°C for 15 minutes. The resulting nanoparticles were characterized by X-ray diffraction (XRD), which reveals that this method led to the formation of CuNi substitutional nanoalloys and bimetallic nanoparticles with good cristallinity related with the calcination temperatures and Cu:Ni weight ratios. Transmission electron microscopy (TEM) shows nearly monodisperse and uniform spherical nanoparticles with sizes between 40 and 70 nm. The magnetic properties were studied using SQUID magnetometry, according with these results, the CuNi nanoparticles showed a ferromagnetic behavior, the magnetization value increases as a function of the weight percentage of Ni.

Layered hydrazinium titanate LHT-9, (N2H5)1/2Ti1.87O4 is a new nanohybrid material related to lepidocrocite-type titanates. Unique combination of ion exchange, reductive properties, surface activity due to Brønsted acid sites and occurrence of surface titanyl groups allows exploring LHT-9 for simultaneous uptake of almost all components of liquid nuclear wastes. LHT-9 irreversibly removes technetium, molybdenum, palladium and selenium from their aqueous solutions by specific mechanism of reductive adsorption. For removal of cesium, strontium, transition elements, actinides and lanthanides LHT-9 provides mechanisms of ion exchange and surface complexation. Products of adsorption are nanocrystalline and homogeneous powders loaded with 5 to 15 wt. % of radionuclides and non-radioactive elements. LHT-9 can be applied as ready-to-use precursor for one-step synthesis of durable titanate ceramic waste forms similar to SYNROC. An essential advantage of LHT-9 in comparison with other titanate sorbents (monosodium titanate and peroxo-titanate materials) is the absence of Na in its composition that permits arbitrary tailoring of sorbent properties by simple pre-treatment with the desired elements. Results on sorption of americium, cesium, strontium and lanthanides by LHT-9 are discussed.

Thin film gallium nitride (GaN) scintillators have been produced by MOCVD and made neutron-sensitive by applying an enriched lithium-6 fluoride (6LiF) conversion layer. The 6Li(n,α) reaction produces both alpha and triton particles, which have very penetration depths in GaN. The range and energy deposition characteristics of these particles in GaN have been simulated. Alpha-induced scintillation was measured in silicon-doped GaN using an americium-241 (241Am) source. The thermal neutron responses of the 6LiF-coated GaN scintillator were tested using two thermal neutron sources, an 241Am-Be source inside a graphite pile and a reactor source. The scintillator was found to have a linear response to thermal neutron flux level over a range of more than three orders of magnitude.

Hydrogen passivation was applied to the initial epitaxial growth of n-type β-FeSi2 thin films on p-type Si(111) substrates by facing-targets direct-current sputtering (FTDCS) in order to reduced the formation of interface states and terminate dangling bonds in the β-FeSi2 films, and the passivation effects were studied on basis of the electrical evaluation results of the formed n-type β-FeSi2/p-type Si heterojunction photodiodes. The initial growth was made at different gas inflow H2/Ar ratios ranging from 0 to 0.2. The photodetection performance of the photodiode fabricated at the ratio of 0.2 was markedly improved as compared to those of the other samples. The quantum efficiency and detectivity were 2.08 % and 1.75 × 1010 cm√Hz/W, respectively. The sample exhibited the minimum junction capacitance density of 9.2 nF/cm2. The enhanced photodetective performance should be mainly because dangling bonds that act as trap centers for photocarriers are effectively inactivated by the passivation.

Opuntia ficus-indica (Ofi) cactus non-gelling (NE) mucilage nanofibers were electrospun with acetic acid solution and polyvinyl alcohol (PVA) as a polymer. The best fiber coverage was achieved with an aqueous 50% acetic acid solution and 9% low molecular weight PVA at a 70:30 PVA:Mucilage volume ratio. Other volume ratios (30:70 and 50:50) produced beads and other deformities. Fibers were formed with an average diameter of 180nm as measured by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Favorable electrospinning conditions were used to fabricate a 1 cm x 1 cm Ofi nanofiber biomembrane. Heat flow (W/g) versus temperature peaks ranged from 214 – 222°C, which is comparable to endothermic peak ranges observed for crystalline PVA. This could possibly further indicate some form of crystallinity within the Ofi nanofiber membrane. The electrospun process used precursors that were biodegradable, non-toxic, and sustainable to optimize the mucilage nanofiber formation, which will help enhance the potential performance of the Ofi nanofiber biomembrane in filtration and sensory systems.

Biodegradable poly(3-hydroxybutyrate) -PHB- and the copolymers with poly (3-hydroxyvalerate) -PHB/HV, containing 5 and 12 mol% valerate (denoted PHB/5HV and PHB/12HV, respectively) were electrospun from chloroform solution at room temperature. The results showed that relatively low voltage and concentrations favored uniform filament formation in PHB, with filament diameters ranging from 3 to 7 micrometers. On the other hand, low molecular weight and low solution concentration favored uniform filament formation in the PHB/5HV copolymer. Strikingly, morphology of filaments and beads favored the membranes hydrophobic behavior; the membrane from PHB/12HV exhibited a water contact angle of 112°. In contrast, solution cast films from the PHAs exhibited water contact angles in the range of 65°. Analyses on the membranes morphology via scanning electron microscopy (SEM) revealed that filament diameter drives the degree of porosity and the hydrophobic behavior of the electrospun membranes.

Aluminum lithium hydroxide carbonate hydrate, also known as Al/Li layered double hydroxide or Al-Li hydrotalcite-like compound [Al2Li(OH)6]2CO3•nH2O, was prepared by reaction of lithium carbonate with ammonium dawsonite [NH4Al(OH)2CO3]. The reaction of ammonium dawsonite with a lithium carbonate satured solution at different temperatures and lithium carbonate concentrations was studied. The obtained solids were characterized by differential thermal analysis (DTA), thermogravimetry (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). By this method, crystalline Li/Al LDH [Al2Li(OH)6]2CO3·3H2O can be obtained at 60 °C and 4 h reaction time.

The fabrication of low-dimensional diamond materials in form of nanowires is a stringent requirement for advanced electronic applications. However, the nanometric control of diamond materials into desired and tailored geometries, as those ones required for applications in the field of nano-photonics, is a really challenging and complex task using currently available processes. In the present paper we describe some recent results obtained using plasma-induced processes for the shaping of diamond films in fascinating 1D structures, such as nanowires, nanowhiskers and nanopillars, to be integrated in devices of technological interest.