bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi-Layered SiC Nanocrystals Embedded in SiO2 Dielectrics for Nonvolatile Memory Application
Authors: Lee Dong Uk , Lee Tae Hee , Kim Eun Kyu , Shin Jin-Wook , Cho Won-Ju 
Published: August 2010

AbstractA nonvolatile memory device with the multi-layered SiC nanocrystals embedded in the SiO2 dielectrics for long-term data storage was fabricated and its electrical properties were evaluated. The SiC nanocrystals were formed by using post thermal annealing process. The transmission electron microscope analysis showed the multi-layered SiC nanocrystals between the tunnel and the control oxide layers. The average size and density of the SiC nanocrystals were approximately 5 nm and 2×1012 cm-2, respectively. The memory window of nonvolatile memory devices with the multi-layered of SiC nanocrystals was about 2.7 V during the operations at ±10 V for 700 ms, and then it was maintained around at 1.1 V after 105 sec.
Metastable Variations of the Fill Factor in CIGS Thin Film Solar Cells
Authors: Urbaniak Aleksander , Igalson Małgorzata 
Published: August 2010

AbstractWe investigate the origin of fill factor changes induced by reverse bias treatment. Evolution of current-voltage characteristics have been measured during application of reverse voltage bias. Two different cell behaviors have been identified. At elevated temperatures one kind of the devices strongly deteriorates and exhibit so called double diode behavior. On the other hand, in the same conditions another cells keep their fill factor almost constant. We correlate the fill factor changes with the kinetics of capacitance and show that although increased number of shallow acceptors itself cannot induce this severe FF deterioration, it may strongly influence position of the Fermi level at the heterointerface that in a presence of an electron barrier is crucial for the device behavior.
Photoluminescence and Photoluminescence Excitation Spectroscopy of Cu(In,Ga)Se2Thin Films
Authors: Hebert Damon N. , Soares Julio A. N. T. , Rockett Angus A. 
Published: August 2010

AbstractThe role of intrinsic point defects on radiative recombination in Cu(In,Ga)Se2thin films was investigated by photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies. Experiments were performed on device-grade polycrystalline layers and single crystal thin films. PL transitions identified by others as indicating a shallow state with an ionization energy of ∼16 meV is proposed to be a transition into band tail states rather than a distinct shallow defect. The presence of deep levels contributing to radiative recombination does not necessarily preclude the material from producing a high efficiency device and may suggest the absence of dominant non-radiative recombination pathways. The band edge width as measured by PLE and the separation of this edge from defect states are suggested to be potentially effective indicators of the quality of a material. Luminescence that appears to be connected with the absence of Na in the growth process persists in high Ga alloy, Na containing materials, suggesting that Na may become ineffective in passivating or eliminating certain defects in high Ga material.
Photocatalysis for the Degradation of Ionic Surfactants in Water: The Case of DPC
Authors: Naldoni Alberto , Bianchi Claudia , Ardizzone Silvia , Cappelletti Giuseppe , Ciceri Luca , Schibuola Alessandro , Pirola Carlo , Pappini Marco 
Published: August 2010

AbstractTraditional techniques to remove contaminants (carbon adsorption, incineration, biological activity and chemical treatment) have a lot of disadvantages. Advanced Oxidation Processes (AOP’s) are used as alternative processes in the degradation of surfactants and in general for wastewater treatment. They are based on the generation of OH•, one of the most powerful oxidant known (E° = 2.73 V) and capable to react non-selectively with any organic compound. In the present work, the degradation of a cationic surfactant (dodecylpyridinium chloride (DPC)) was performed. The photodegradation reaction was investigated both in a slurry reactor and in a vessel where the photocatalyst (P25 by Degussa) was anchored onto an aluminum surface to avoid the final filtration of the powder at the end of the reaction. Moreover a new photoreactor was built on purpose to investigate the influence of the pressure on the degradation process.
Surface Plasmon Resonance with Electrospun Nanofibers on Gold Surface
Authors: Tsuboi Kazuma , Matsumoto Hidetoshi , Minagawa Mie , Tanioka Akihiko 
Published: August 2010

AbstractIn this paper we report new excitation method of surface plasmon polariton (SPP) at air/gold interface with electrospun nanofibers. Nanofibers of polyvinylpirrolidone were electrospun onto the surface of a gold film. The observations by scanning electron microscopy and optical microscopy indicated that the average diameters of the nanofibers were about 300 nm and average sizes of pores were about 30-40 μm. Optical response of the nanofibers on gold surface was investigated by polarized reflection absorption spectroscopy (RAS). The RAS spectrum with p-polarized light showed two absorption bands while the spectrum with s-polarized light only one band. One is a band at about 520 nm that also found in the spectrum with s-polarized light. Another is a broad band in the near-infrared region which found only with p-polarized light. The peak intensity of the latter band increases with increase of incident angle of the polarized light and the peak wavelength of the band shifted to longer wavelength. These responses suggested that SPP at air/gold interface was excited with the scattering light from the electrospun nanofibers. We also found that the peak wavelength of the absorption band in near-infrared region changed with the increase of the amount of the nanofibers. This may be due to the fact that the sizes of the pores on gold surface became smaller than the propagation length of SPP, which resulted in scattering and interference of SPP.
Synthesis and Characterization of Nanocarbon-Supported Titanium Dioxide
Authors: Worsley Marcus A , Kuntz Joshua D. , Cervantes Octavio , Han T Yong-Jin , Pauzauskie Peter , Satcher Joe H , Baumann Theodore F 
Published: August 2010

AbstractIn this report, we describe recent efforts in fabricating new nanocarbon-supported titanium dioxide structures that exhibit high surface area and improved electrical conductivity. Nanocarbons consisting of single-walled carbon nanotubes and carbon aerogel nanoparticles were used to support titanium dioxide particles and produce monoliths with densities as low as 80 mg/cm 3. The electrical conductivity of the nanocarbon-supported titanium dioxide was dictated by the conductivity of the nanocarbon support while the pore structure was dominated by the titanium dioxide aerogel particles. The conductivity of the monoliths presented here was 72 S/m and the surface area was 203 m2/g.
Trends of Nanoclusters' Growth by Physical Vapor Deposition Studied by Atomistic Simulation
Authors: Bhuiyan Abuhanif , Dew Steven K. , Stepanova Maria 
Published: August 2010

AbstractEfficient methodologies for synthesis of nanocrystals (NC) are a crucial component for creation of nanostructured electronic components. Physical vapor deposition (PVD) is one of the most flexible techniques to fabricate self-assembled arrangements of nanoclusters. Controllable fabrication of such assemblies can improve reliability of nanocapacitors, enhance performance of magnetic memories, and has many applications in opto-electronics devices, etc. However, size, shape and density of nanocrystals are highly sensitive to the process conditions such as duration of deposition, temperature, substrate material, etc. To efficiently synthesize nanocrystalline arrays by PVD, the process control factors should be understood in greater detail. In this work, we present a kinetic Monte Carlo (KMC) model and report simulations that explicitly represent the PVD synthesis of nanocrystals on substrates. Here we study how varying the most important process parameters affects the morphologies of self-assembled metallic islands on substrates. We compare our results with experimentally observed surface morphologies generated by PVD and demonstrate that KMC models like this are an efficient tool for computer-aided design of PVD processes for synthesis of nanocrystals.
Combined AFM-SEM for mechanical testing of fibrous biological materials
Authors: Hang Fei , Lu Dun , Barber Asa H 
Published: August 2010

AbstractA technique combining both atomic force microscopy (AFM) and scanning electron microscopy (SEM) is used to evaluate the mechanical properties of individual collagen fibrils from the fractured surface of antler. SEM is used to locate individual mineralized collagen fibrils and allow visualization of the attachment of these fibrils to the end of an AFM probe. Tensile testing of individual collagen fibril to failure was performed using the AFM with resultant stress-strain curves obtained. Tensile strengths of up to 0.18GPa are found for some individual collagen fibrils, indicating the presence of mineral in improving mechanical performance. Consideration of the SEM operating parameters indicates that the amount of time the sample is within the SEM vacuum can affect the resultant mechanical behavior of individual fibrils.
The Role of the Organic Component in the Mechanical Behavior of Biomineralized Composites
Authors: Mayer George , Zhou Jason 
Published: August 2010

AbstractThe roles of minor organic layers in influencing the mechanical response of such biomineralized composites as mollusk shells and sponge spicules have been investigated. The mechanisms whereby such minor constituents govern energy dissipation in rigid biomineralized structures are discussed, and a rationale for new modes of toughening that may relate more generally to families of ceramic- or glass/organic composites is offered. New results of simple torsional tests conducted on spicule fibers of a hexactinellid sponge, Euplectella aspergillum (Euplectella a.), compared with those done on melt-drawn glass fibers, showed an enhanced ability to resist failure in torsion, whereas the glass fibers did not. This behavior was attributed to the presence of a very thin adhesive viscoelastic phase between the siliceous layers of the spicule fibers, combined with the architectural and surface features of the spicule fiber.
Epitaxial Growth of Highly Crystallized InSb films on Si Substrate by MBE and Their Devices Properties
Authors: Kunimi Yoshihisa , Fujita Hiromi , Sakurai Ayano , Akiyama Shinichiro , Miyahara Masatoshi , Shibata Yoshihiko 
Published: August 2010

AbstractHigh crystallized thin InSb epitaxial growth directly on Si substrate was investigated by molecular-beam epitaxy (MBE). Experimental results indicated that suppressing the desorption of hydrogen atoms which terminated the dangling bonds of Si wafer surface and incorporation of As around the interface between film and Si substrate were the most important to obtained high crystallized InSb film. It could be achieved by the irradiation of As4 cluster beam onto the Si wafer just before film growth. Obtained thin InSb film showed mirror like surface, and its thickness was 0.7 μm. Its electron mobility was 47,600 cm2/V-s, and FWHM of HR-XRD rocking curve was about 300 arcsec. This InSb film on Si wafer was applied to Hall element, and it passed ordinary reliability tests.
Mechanical Sintering Techniques for Printed Electrodes with Various Work-function on a Plastic Substrate
Authors: Yoshida Manabu , Suemori Kouji , Uemura Sei , Hoshino Satoshi , Takada Noriyuki , Kodzasa Takehito , Kamata Toshihide 
Published: August 2010

AbstractA print technique of an electrode on a plastic substrate is one of the most important techniques for developing a printed large area device. Especially, preparation of a metal electrode with low work function by printing is very important to develop printed active devices such as diode and transistors. Work function values of electrodes strongly affect device properties (1,2), because the work function difference between a semiconductor and an electrode is related to charge injection from the electrode to the semiconductor. Recently, many solution-processable n-type semiconductors have been developed (3), because these are required to fabricate printable EL devices, printable CMOS devices, and so on. Low-work function metals are necessary to inject electrons to n-type semiconductor. In spite of this fact, very few printable low-work function metal inks have been developed, because low-work function metals are easily oxidized during print process owing to high temperature annealing treatment and their conductivities are lost.In this study, we have examined to develop a new annealing technique on a printed electrode to reduce the process temperature during metal printing. We have newly developed a mechanical sintering technique in which mechanical forces is applied on a printed metal pattern. Control of the direction balance of applied mechanical force was effective to reduce resistivity of the printed metal without any destruction of plastic substrate. Furthermore, distribution control of metal particle in the metal ink was also effective to reduce resistivity. By using this technique, we have succeeded in the preparation of an aluminum, zinc, copper and tin electrode on a plastic substrate. On the other hand, we have tried to prepare a metal alloy ink to control the work function of printed electrode. Metal alloy ink was composed of two kinds of metal particles. Work function of the electrode was controlled by changing composition of these metal contents in an alloy ink. By applying our developed mechanical sintering technique on the printed alloy pattern, printed electrode with various work functions from 3.5eV to 5eV could be prepared on a plastic substrate. These printed alloys were effective to improve the performance of printed diode and transistors.
Manipulation of Room Temperature Ferromagnetic behavior of GaMnN Epilayers
Authors: Nepal Neeraj , Luen M. Oliver , Frajtag Pavel , Zavada John , Bedair Salah M. , El-Masry Nadia 
Published: August 2010

AbstractWe report on metal organic chemical vapor deposition growth of GaMnN/p-GaN/n-GaN multilayer structures and manipulation of room temperature (RT) ferromagnetism (FM) in a GaMnN layer. The GaMnN layer was grown on top of a n-GaN substrate and found to be almost always paramagnetic. However, when grown on a p-type GaN layer, a strong saturation magnetization (Ms) was observed. Ms was almost doubled after annealing demonstrating that the FM observed in GaMnN film is carrier-mediated. To control the hole concentration of the p-GaN layer by depletion, GaMnN/p-GaN/n-GaN multilayer structures of different p-GaN thickness (Xp) were grown on sapphire substrates. We have demonstrated that the FM depends on the Xp and the applied bias to the GaN p-n junction. The FM of these multilayer is independent on the top GaMnN layer thickness (tGaMnN) for tGaMnN >200 nm and decreases for tGaMnN < 200 nm. Thus the room temperature FM of GaMnN i-p-n structure can also be controlled by changing Xp and tGaMnN in the GaMnN i-p-n structures.
Pulsed Laser Deposition as a Novel Growth Technique of Multiferroic LuFe2O4 Thin Films
Authors: Rejman Jason , Dhakal Tara , Mukherjee Pritish , Srikanth Hariharan , Witanachchi Sarath 
Published: August 2010

AbstractGrowth of polycrystalline Lutetium Iron Oxide via pulsed laser deposition in thin film form is reported for the first time herein, and the multiferroic LuFe2O4 phase is stabilized. Fluence and pressure dependent phase growth is demonstrated, along with crystalline structure in vacuum (˜10-5 torr) conditions. Thermodynamic considerations at the laser-target interaction were investigated, as well as at the plume-substrate interface, which reveal that the necessary Gibbs free energy is available in the optimized growth environment to allow formation of the LuFe2O4 polycrystalline phase. The resulting growth rate is found to be related to the Gibbs free energy and concentration of nucleation sites on the substrate. Characterization of the multiferroic aspect of LuFe2O4 entailed direct measurement of the ferroelectricity in the thin film, as well as magnetic behavior, both at various temperatures. In particular, the ferroelectric polarization vs. voltage data yield values of 0.61 μC/cm2 at 300 K to 3.29 μC/cm2 at 183 K; moreover, these data are in agreement with those reported in the literature. Magnetization vs. applied field data shows the magnetization at 300 K to be 180 emu/cm3 and increasing to 200 emu/cm3 at 10 K.
Structural Characterization of Cu2+Functional Centers In ‘Lead-Free’ KNN Piezoelectrics
Authors: Erünal Ebru , Eichel Rüdiger-A. , Acker Jerome , Kungl Hans , Hoffmann Michael J. 
Published: August 2010

AbstractThe alkali niobate ferroelectrics ((K0.5Na0.5)NbO3, KNN) are promising candidates as alternatives for PZT (Pb(ZrxTi(1-x))O3) ceramics in piezoelectric technologies. In order to obtain dense compounds with desirable properties, CuO has been used as sintering aid. In this work, the defect chemistry of Cu2+doped KNN was investigated by means of electron paramagnetic resonance (EPR). Copper is found to be incorporated as acceptor-type centers on B-site in the perovskite structure and, due to charge compensation, two kinds of mutually compensating defect dipoles are formed.
Comparative Study of the Magnetocaloric Properties in Ni-Mn-X (X = Ga, In, Sn) by Magnetization and Specific Heat Measurements
Authors: Khovaylo V V , Skokov K P , Avilova E V , Novosad Val , Miki H , Kainuma Ryosuke , Wang G , Palacios E , Bartolomé J , Burriel R 
Published: August 2010

AbstractSome compositions of Ni-Mn-X (X = Ga, In, Sn) ferromagnetic shape memory alloys exhibit a first order magnetostructural phase transition. Magnetic entropy change ΔSm in the vicinity of this transition has been studied by magnetization and heat capacity measurements. Comparison of these results point to a large difference in magnitudes of ΔSm obtained from magnetization and heat capacity data. It is suggested that this discrepancy originates from overestimation of \Delta S_m determined from the magnetization measurements and underestimation of ΔSm obtained from the heat capacity measurements.
Thermal Annealing Influence on Magnetic and Structural Properties of Cu56Ga28Mn16 Microwires
Authors: Prida Víctor , Vega Victor , Sanchez Llamazares Jose , Sanchez Maria L , Santos Jesus D , Hernando Blanca , Escoda Lluisa , Suñol Joan J , Garcia Carlos , Ross Caroline 
Published: August 2010

AbstractWe report on the crystalline structure, morphology and thermomagnetic properties of glass-coated magnetic microwires with Cu56Ga28Mn16 composition, as well as the thermal annealing influence on its magneto-structural properties. As-cast CuMnGa microwires exhibit a majority cubic B2 phase, and upon annealing at temperatures up to 573 K a new hexagonal phase appears coexisting with the cubic B2 major phase. Thermal annealing treatments also shift the Curie temperature about 150 K with respect to the one for the as-cast microwire. Furthermore, the signature of a structural phase transition is observed for the microwire annealed at 523 K
Study of the Adhesion and Biocompatibility of Nanocrystalline Diamond (NCD) Films on 3C-SiC Substrates
Authors: Gomez Humberto , Frewin Christopher L. , Kumar Ashok , Saddow Stephen , Locke Christopher 
Published: August 2010

AbstractThe unique material characteristics of silicon carbide (SiC) and nanocrystalline diamond (NCD) present solutions to many problems in conventional MEMS applications and especially for biologically compatible devices. Both materials have a wide bandgap along with excellent optical, thermal and mechanical properties. Initial experiments were performed for NCD films grown on 3C-SiC using a microwave plasma chemical vapor deposition (MPCVD) reactor. It was observed from the atomic force microscopy (AFM) analysis that the NCD films on 3C-SiC possess a more uniform grain structure, with sizes ranging from approximately 5 – 10 nm, whereas on the Si surface, the NCD has large, non-unioform inclusions of grains ≈1 μm in size. The in vitro biocompatibility performance of NCD/3C-SiC was measured utilizing 2 immortalized neural cell lines: H4 human neuroglioma (ATCC #HTB-148) and PC12 rat pheochromocytoma (ATCC #CRL-1721). MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to measure viability of the cells for 96 hours and live/ fixed cell. AFM was performed to determine the general cell morphology. The H4 cell line shows a good biocompatibility level with hydrogen treated NCD as compared with the cell treated polystyrene control well, while the PC12 cells show decreased viability on the NCD surfaces.
Synthesis of Few-Layer and Multi-Layer Graphene and Fabrication of Top-Gated Field Effect Transistors without Using Transferring Processes
Authors: Kondo Daiyu , Yagi Katsunori , Harada Naoki , Sato Motonobu , Nihei Mizuhisa , Sato Shintaro , Yokoyama Naoki 
Published: August 2010

AbstractWe have fabricated top-gated field effect transistors (FETs) using graphene synthesized by chemical vapor deposition directly on a SiO2/Si substrate without using any transferring processes. Graphene was synthesized on an Fe catalyst film on the substrate at 650°C. The catalyst film was then etched after both ends of the graphene were fixed by source and drain electrodes, leaving the graphene channel connecting the two electrodes. Top-gated FETs were then made by covering graphene channels with HfO2 and depositing top electrodes. The drain current was successfully modulated by the gate voltage and exhibited the bipolar behavior that is characteristic of graphene. Also, it has been shown that graphene channels can sustain an electric current with a density of 107–108 /cm2. Our newly developed fabrication process paves a way to fabricate graphene transistors all over large substrates including Si and glass.
Incoherent Transport in Nanowire - The Effect of Electron-phonon Interaction
Authors: Nishizawa Hideyuki , Itoh Satoshi 
Published: August 2010

AbstractThe incoherent transport model based on electron-phonon interaction was introduced for calculating the current-voltage characteristics of the nanowire conductor. The current-voltage characteristics of silicon nanowire calculated based on this model was discussed. The charge transport was described by the rate equation containing the coherent (tunneling) and incoherent (energy dissipation) rates, and the incoherent rate was calculated from the Hamiltonian in which the electron-phonon interaction was incorporated. The coherent transition corresponds to the electronic transition between electrode states and channel states without any energy dissipation. On the other hand, the incoherent transition corresponds to the electronic transition between electrode states and channel states where the energy difference of those two states means a thermal dissipation. Therefore, in order to carry out the calculation by the rate equation, the density of states (DOSs) of the carriers in electrode and the channel and the DOS of the phonon in the channel are needed. The current-voltage characteristics were calculated by using the DOS of n-type semiconductor for the electrode and by using intrinsic semiconductor DOS for the channel. In addition, the calculation was performed by using the DOS of the silicon nanowire phonon.