Nickel silicide nanocrystals (NCs) were formed by thermally annealing SiOxNy films either implanted with Ni or coated with an evaporated Ni film. It is observed that the NCs grow into well-defined single crystalline structures embedded in a SiOxNy matrix, and that their size can be directly controlled by adjusting the concentrations of either silicon or nickel in the SiOxNy layer. The formation of well-defined NC monolayers was also demonstrated by depositing an ultra-thin Ni layer between two SiOxNy layers. These structures are shown to exhibit characteristic capacitance-voltage hysteresis suitable for nonvolatile memory applications.

Current semiconductor devices have been scaled to such dimensions that we need take an atomistic approach to understand their characteristics. The atomistic nature of these devices provides us with a tool to study the physics of very small ensembles of dopants right up to the limit of a single atom. Control and understanding of a dopants wavefunction and its coupling to the environment in a nanostructure could proof a key ingredient for device technology beyond-CMOS. Here, we will discuss the eigenlevels and transport characteristics a single gated As donor. The donor is incorporated in the channel of wrap-around gate transistors (FinFETs). The measured level spectrum is shown to consist of levels associated with the donors Coulomb potential, levels associated with a triangular well at the gate interface and hybridized combinations of the two. The level spectrum of this system can be well described by a NEMO-3D model, which is based on a numerical tight-binding approximation.

Hot isostatically pressed (HIPed) glass-ceramics for the immobilization of uranium-rich intermediate-level wastes and Hanford K-basin sludges were designed. These were based on pyrochlore-structured Ca(1-x)U(1+y)Ti2O7 in glass, together with minor crystalline phases. Detailed microstructural, diffraction and spectroscopic characterization of selected glass-ceramic samples has been performed, and chemical durability is adequate, as measured by both MCC-1 and PCT-B leach tests.

Graphitic shells coated ferromagnetic cobalt nanoparticles (C-Co-NPs) with diameters of around 7-9 nm cubic crystalline structures were synthesized by catalytic chemical vapor deposition (CCVD). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis indicated that the Co-NPs inside the carbon shells were preserved in the metallic state. Confocal microscope images revealed effective penetrations of C-Co-NPs through plasmatic membranes into the nucleus of the cultured HeLa cancerous cells. Low RF radiation of 350 kHz triggered the cell death, process that was found to be dependent on the NPs concentration and application time. Compared to carbon nanostructures such as single wall carbon nanotubes, super paramagnetic cobalt nanoparticles demonstrated higher specificity for RF absorption and heating. This work indicates a great potential of a new technology for tumor thermal ablation.

This work reports on the fabrication and characterization of Mo thin films on soda-lime glass substrate grown by reactive RF magnetron sputtering. Film thickness was measured by x-ray step surface profiler. The structural properties and surface morphology were analyzed by x-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM). Electrical properties were measured by four-point probe. It was found that the growth parameters, such as argon flow rate, RF power, film thickness, have significant influences on properties of Mo films. The strain on films revealed the complicated relationship with the working pressure, which might be associated with micro structures and impurities. In order to improve the adhesion and electricity, we adopted a two-pressure deposition scheme. The optimal thickness and sheet resistance are νm and 0.12 ω The mechanisms therein will be discussed in detail. Furthermore, we also investigated the diffusion property of Na ion of double Mo films sputtered on soda-lime glass. Our experimental results could lead to better understanding for improving further CIGS-based photovoltaic devices.

We report NiSi and Ni(Pt)Si films with excellent thermal stability showing a particular crystal orientation on Si(001). The Ni-silicide film with a deposition temperature of about 200 °C consists of a conformal domain structure. We examined detail crystallographic analysis of silicide and clarified the psudo-epitaxial growth of NiSi(202)//Si(220) [or NiSi(211)//Si(220)] was the key scheme of superior thermal stability. By using this optimized Ni-silicide formation process, we have fabricated Ni-silicide that is thermally stable up to 650 °C and shows low fluctuation in sheet resistance and low leakage current in electrical measurements. This process is a promising candidate for future silicidation technology.

Melt-spun Fe73-Si16-B7-Nb3-Cu1 (at%) amorphous strip was pulverized and then crystallized to obtain nano-grain structure at 540° for 1h under a nitrogen atmosphere. Carbon black of 0.1∼ 1wt% and its dispersant were mixed with the nano-grain structured Fe-based powder for 1h via ball milling for 1h. The mixture was tape-cast with a polymer-based organic binder, and dried at 100° to make a thin sheet. The microstructure and electromagnetic wave absorption properties of the sheet were investigated using a network analyzer. As a result, the properties of electromagnetic wave absorption were improved by the increase of dielectric loss, which was mainly caused by the increase of complex permittivity with the addition of carbon black.

Lithium Niobate doped with 4f-ions is of great interest for both fundamental science and advanced applications including high efficiency lasers with frequency conversion, elements for an all-optical telecommunication network and quantum cryptography. Our study has shown that 4f-ions create an unexpected variety of completely different non-equivalent centers in both stoichiometric and lithium deficient congruent crystals. Dominant Nd1 and Yb1 centers have C3 point symmetry (axial center), whereas all Er and most other Nd and Yb centers have the lowest C1 symmetry. Distant defects create small distortions of the crystal field at the impurity site, which cause line broadening, but do not change the C3 symmetry of observed EPR spectra. Defects in the near neighborhood can lower center symmetry from C3 to C1. We concluded that Nd1 has distant charge compensation, whereas the charge excess in low-symmetry Nd(Li) centers is compensated by near lithium or niobium vacancies. Since no axial centers were found for Er, models with cation vacancies can not describe our experimental data. The dominant axial Yb1 center has no defects in its surrounding. One axial and one low-symmetry Yb centers are self compensating Yb(Li)-Yb(Nb) pairs. Six other centers are different complexes of Yb3+ and intrinsic defects. Obtained data can be used for defect engineering for tailoring properties of photonic materials.

The growth of thick silicon carbide (SiC) epitaxial layers for large-area, high-power devices is described. Horizontal hot-wall epitaxial reactors with a capacity of three, 3-inch wafers have been employed to grow over 350 epitaxial layers greater than 100 μm thick. Using this style reactor, very good doping and thickness uniformity and run-to-run reproducibility have been demonstrated. Through a combination of reactor design and process optimization we have been able to achieve the routine production of thick epitaxial layers with morphological defect densities of around 1 cm−2. The low defect density epitaxial layers in synergy with improved substrates and SiC device processing have resulted in the production of 10 A, 10 kV junction barrier Schottky (JBS) diodes with good yield (61.3%).

In an extension of earlier work, the temperature dependent parameters of PVDF operating in the length mode have been measured at frequencies useful in air ultrasound (20kHz to 100kHz) over a -45°C to +65°C temperature range. The length mode resonance of PVDF strips of different lengths was excited by mechanically clamping samples at the mid point during dielectric impedance testing conducted in a desiccated thermal chamber. Material properties were extracted from the impedance magnitude and phase angle data at temperature, and the various sample lengths allowed a range of resonant frequencies to be studied. Overall results generally confirm the visco-elastic behavior of PVDF. Testing was conducted on samples with both thin sputtered metal electrodes (∼60nm) and thicker elastomeric silver ink electrodes (∼8μm) to assess the performance difference. Silver ink is preferred in production as sputtered metal has current density an other limitations, but it causes a serious loss in performance at high frequencies.

Hydrogenated amorphous silicon (a–Si:H) n–i–p photodiodes are used as pixel sensor elements in large-area flat-panel detectors for medical imaging diagnostics. Accurate model of the sensor plays an imperative role in determining the performances of the detector systems as well as ascertaining design issues prior to production. This work presents the formulation of a compact model for segmented a–Si:H n–i–p photodiodes suitable for circuit-level simulation. The underlining equations of the model are based on device physics where the parameters are extracted from pertinent measurement results of previously fabricated a–Si:H n–i–p photodiodes. Furthermore, the implemented model allows photoresponse simulation with the addition of an external current source. Results of the simulation demonstrated excellent matching with measurement data for different photodiode sizes at various temperatures. The model is implemented in Verilog-A and simulated under Cadence Virtuoso design environment using device geometry and extracted parameters as inputs. The model formulation and parameter extraction process, as well as measurements and simulation results are presented.

A range of mineral content values and organization of the collagen and mineral phases are possible contributors to the significant variance demonstrated within the nanomechanical behavior of mineralized tissues. A combined approach using nanoindentation, to assess nanomechanical behavior, and X-ray diffraction, for analysis of crystallinity and composition, were used to investigate a range of modern and fossilized bone samples. This work provides new insight into the functional role of organization and composition of the mineral phase within heterogeneous, mineralized materials of biological origin. While the predominant influence on nanomechanical behavior is made by mineral volume fraction, the crystallinity was shown to play a significant role in the nanomechanical behavior of modern and fossilized bone samples. The interplay between material structure and function will ultimately help to elucidate the relative contributions of various factors to nanomechanical behavior and lead to improved development of biomimetic materials.

Electrical resistivity measurements performed under applied hydrostatic pressure and in magnetic fields have been used to probe the hidden order (HO) and superconducting (SC) states of URu2Si2, which have ambient-pressure transition temperatures TO = 17.5 K and Tc = 1.5 K, respectively. TO increases with applied pressure and a distinct kink in its pressure dependence is observed at 15 kbar; this feature is associated with the onset of antiferromagnetism. The pressure dependence of the SC upper critical field has been measured with the external field aligned parallel to both crystalline axes. The SC phase is smoothly suppressed to a critical pressure of about 15 kbar and no qualitative change in the critical field curves is observed. The co-evolution of the HO and SC phases is discussed within the context of a model in which the two phases compete for Fermi surface fraction.

Yttria-stabilized zirconia (YSZ) is one of the most common electrolytes in high temperature solid oxide fuel cell (SOFCs). We utilize atomic layer deposition (ALD) to fabricate the electrolyte of SOFC, which may potentially improve several fundamental characteristics of SOFC. Recently, our group demonstrated that ultra-thin ALD YSZ SOFSs can deliver high power density at low temperatures [1]. These SOFCs demonstrated not only reduction of Ohmic loss, but also enhancement of surface kinetics.

The focus of this work is to investigate the surface and bulk conduction characteristics of YSZ films produced by ALD. In plane conductivity was measured as a function of film thickness and temperature dependence. YSZ thin films were deposited on standard 4 ” quartz substrates with thicknesses ranging from 8 nanometers to 55 nanometers. Micro-electrodes were patterned on top of the ALD YSZ layer by standard photolithography process. The impedances of the YSZ thin films with different thicknesses were measured. We have observed higher conductivities for thinner films which were attributed to higher oxide ion conductivity in the vicinity of the surface, and similar phenomenon was observed with YSZ films produced by electron beam evaporation [2].

Photonic crystal surfaces represent a class of resonant optical structures that are capable of supporting high intensity electromagnetic standing waves with near-field and far-field properties that can be exploited for high sensitivity detection of biomolecules and cells. While modulation of the resonant wavelength of a photonic crystal by the dielectric permittivity of adsorbed biomaterials enables label-free detection, the resonance can also be tuned to coincide with the excitation wavelength of common fluorescent tags - including organic molecules and semiconductor quantum dots. Photonic crystals are also capable of efficiently channeling fluorescent emission into a preferred direction for enhanced extraction efficiency. Photonic crystals can be designed to support multiple resonant modes that can perform label free detection, enhanced fluorescence excitation, and enhanced fluorescence extraction simultaneously on the same device. Because photonic crystal surfaces may be inexpensively produced over large surface areas by nanoreplica molding processes, they can be incorporated into disposable labware for applications such as pharmaceutical high throughput screening. In this talk, the optical properties of surface photonic crystals will be reviewed and several applications will be described, including results from screening a 200,000-member chemical compound library for inhibitors of protein-DNA interactions, gene expression microarrays, and high sensitivity of protein biomarkers.

We studied the anisotropic charge transport properties of solution-grown organic single crystals based on a dipolar molecule 4HCB (4-hydroxy-cyanobenzene) by electrical transport measurements, current-voltage and space charge limited current (SCLC), and by X-ray diffraction analyses.

Optical excitation differently affects the flow of charge carriers along the two main planar crystal axis, altering the charge transport anisotropy induced by the molecular π-orbitals stacking.We attribute this behaviour to the presence of an intrinsic molecular dipole and to its different orientation within the crystal lattice. The anisotropy of transport along the three crystallographic directions has been assessed by electrical characterization and correlated to the crystal molecular packing as determined by X-ray analyses.

Amorphous silicon based solar modules are very attractive for the powering of various microsystems for both indoor and outdoor applications. This technology offers a lot of flexibility in terms of module design, output voltage, shape, size, choice of substrates and offers also the possibility to embed sensors such as photodiodes. This paper focuses on the development of micro-solar modules with area ≤0.15 cm2. Several micro-modules with output voltage of up to 60 V (form 0.1 cm2) were designed and fabricated. The performance limitation introduced by the segment monolithic interconnection and the design of the latter is presented and discussed. An example of a micro-module with a total size of 3.9×3.9 mm2 developed for a micro-robot with dual voltage outputs and embedded photodiodes is also presented.

In our previous studies, thin Ti-rich diffusion barrier layers were found to be formed at the interface between Cu(Ti) films and SiO2/Si substrates after annealing at elevated temperatures. This technique was called “self-formation of the diffusion barrier,” which is attractive for fabrication of ultra-large scale integrated (ULSI) interconnects. In the present study, we investigated the applicability of this technique to Cu(Ti) alloy films which were deposited on the four low dielectric constant (low-k) dielectric layers which are potential dielectric layers of future ULSI-Si devices. The microstructures were analyzed by transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS), and correlated with the electrical properties of the Cu(Ti) films. It was concluded that the Ti-rich interface layers were formed in all the Cu(Ti)/dielectric-layer samples. The primary factor to control composition of the self-formed Ti-rich interface layers was the C concentration in the dielectric layers rather than the formation enthalpy of the Ti compounds (TiC and TiSi). Crystalline TiC was formed on the dielectric layers with a C concentration higher than 17 at.%.

Well established quartz crystal microbalance with dissipation (QCM-D) monitoringtechnique has been applied here for investigation the adsorption kinetics of three different proteins (BSA, IgG, Lysozyme) on thin film of liquid crystal copper octakishexylthiophthalocyanine [(C6S)8PcCu] surface. Modification of phthalocyanine surface by protein coating can be useful for photo dynamic therapy or in biomedical devices purpose in order to increase biocompatibility. The adsorption kinetics on vertically oriented molecular stacks of phthalocyanines were different for three proteins. Lysozyme reached to saturation quickly compare to BSA and IgG. Changes in resonance frequency and dissipation for three overtones were fitted with the Voigt viscoelastic model to calculate the shear viscosity and shear elastic modulus for the adsorbed proteins. Sauerbrey equation was used to calculate approximate adsorbed mass directly from frequency change. Adsorbed mass calculated from Voigt model was different from Sauerbrey equation. Hydration level of adsorbed protein layer was calculated from the difference in mass based on above two methods which was increased with concentration from 10-80% for BSA and IgG whereas it decreased from 20-1% for Lysozyme. Variation of viscosity and shear elastic modulus with concentration is opposite for BSA, IgG than Lysozyme. Depending on the hydration levels, adsorbed BSA and IgG formed soft (viscoelastic) layer compare to rigid layer of Lysozyme on (C6S)8PcCu surface.

Indentations were performed on silicon using a Berkovich indenter at loads up to 12 mN, at temperatures from 20 to 135 °C. Transmission electron microscopy revealed crystalline silicon phases in the residual indentation imprint at and above 35 °C. Also, the first reconfirmation of the occurrence of Si-VIII during unloading was observed at temperatures of 100 and 125 °C. Interestingly, at 125 °C a cavity was also observed, and an unidentifiable phase was observed at 135 °C. The observations show the strong effect of temperature on pressure-induced phase transformation in silicon.