bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon Nanotubes as Optical Materials
Authors: Lu Shaoxin , Shao Ning , Liu Ye , Panchapakesan Balaji 
Published: April 2011

AbstractThis paper discusses some of the highly interesting effects that occur when photons interact with carbon nanotubes. From position dependent photoconductivity of nanotube thin films to photon induced elastic actuation of carbon nanotubes is presented. A new field of micro-opto-mechanical systems (MOMS) is envisioned through the miniaturization of nanotube actuators using MEMS and CMOS processes. Number of remotely controlled MOMS devices including MOMS grippers, MOMS cantilevers and MOMS mirrors are presented. The performance of these devices rivals their MEMS electrostatic counterparts while consuming only fraction of energy and enabling remote controllability. Finally, the interaction of light with nanotubes for biomedical nanotechnology and photodynamic cancer therapy is presented.
Antireflection Coating for External-Cavity Quantum Cascade Laser Near 5 THz
Authors: Fenner David B. , Hensley Joel M. , Allen Mark G. , Xu Jihua , Tredicucci Alessandro 
Published: April 2011

AbstractWe report a simple and practical method to design and fabricate antireflection (AR) coatings for the emission facet of GaAs-based laser chips suited to operating in the very far infrared (IR) or terahertz (THz) spectral region. Vacuum-deposited silica films about 8 Ým thick serve as a single layer, quarter-wave AR and with reflectivities measured below 0.5% over ~10 cm-1 range in the far IR. Quantum cascade lasers (QCL) thus coated function well at 8-10 K coupled to a tunable, external cavity optical system at ~158 cm-1 (∼4.75 THz).
Effects of Chirality and Diameter on Electron Transport Properties in Individual Semiconducting Carbon Nanotubes
Authors: Kauser M. Zahed , Ruden P. Paul 
Published: April 2011

AbstractWe report on the effects of chirality and diameter on the electron transport properties in individual semiconducting, single wall carbon nanotubes. The Boltzmann transport equation is solved indirectly by the Ensemble Monte Carlo method and directly by Rode's iterative technique. Results show considerable effects of chirality and group on band structure and transport properties of tubes with small diameters. However the effects of chirality and group become negligible for tubes with large diameters. Diameter affects these properties more strongly than either chirality or group.
In Situ Synchrotron X-ray Absorption Experiments and Modelling of the Growth Rates of Electrochemically Deposited ZnO Nanostructures
Authors: Ingham Bridget , Illy Benoit N. , Mackay Jade R. , White Stephen P. , Hendy Shaun C. , Ryan Mary P. 
Published: April 2011

AbstractZnO is known to produce a wide variety of nanostructures that have enormous scope for optoelectronic applications. Using an aqueous electrochemical deposition technique, we are able to tightly control a wide range of deposition parameters (Zn2+ concentration, temperature, potential, time) and hence the resulting deposit morphology. By simultaneously conducting synchrotron x-ray absorption spectroscopy (XAS) experiments during the deposition, we are able to directly monitor the growth rates of the nanostructures, as well as providing direct chemical speciation of the films. In situ experiments such as these are critical to understanding the nucleation and growth of such nanostructures.Recent results from in situ XAS synchrotron experiments demonstrate the growth rates as a function of potential and Zn2+ concentration. These are compared with the electrochemical current density recorded during the deposition, and the final morphology revealed through ex situ high resolution electron microscopy. The results are indicative of two distinct growth regimes, and simultaneous changes in the morphology are observed.These experiments are complemented by modelling the growth of the rods in the transport-limited case, using the Nernst-Planck equations in 2 dimensions, to yield the growth rate of the volume, length, and radius as a function of time.
Electrodeposition of Bismuth Telluride Nanowires for Thermoelectric Applications
Authors: Scheffler Raymond H. , Ye Qi Laura , McNeil Melanie 
Published: April 2011

AbstractBismuth telluride (Bi2Te3) and its alloys have long been held as the best bulk commercial thermoelectric (TE) materials. In recent years, significant enhancement of the TE figure of merit (ZT) of these traditional TE materials has been predicted through reduction of dimensions (i.e., nanostructures and nanoengineering). We are particularly interested investigating electrolyte composition variations to control the composition of nanowires to enable large ZT enhancement. We report here the constant current electrochemical deposition of BixTey nanowires of diameters of 35, 55, 73 and 200 nm and lengths up to 50 microns. We are able to obtain controlled, uniform growth of high quality n-type bismuth telluride nanowires. A design of experimental matrix investigating the effects of current density and solution pH values on the overall growth rate and nanowire crystalline quality has been performed. The effects of growth conditions on materials and structural characteristics of BixTey nanowires have been studied by SEM, High Resolution TEM, EDX, concentric beam electron diffraction patterns, and ICP. The TE properties of individual BixTey nanowires are currently being evaluated using micro/nano fabricated devices and UHV Scanning Thermoelectric Microscopy.
Patterned Adhesion of Cells
Authors: Zimmerman Robert Lee , Gurhan Ismet , ILA Daryush 
Published: April 2011

AbstractIt is well known that silver deposition avoids bacterial growth and inhibits the natural process of attachment of connective tissue to biocompatible materials in vivo. We have completed a five year investigation of the precise spatial control of cell growth on glassy polymeric carbon implanted with silver using ion beam techniques, and the persistence of the inhibitory effect on cell growth. Long term inhibition of cell growth on GPC is a desirable improvement on current cardiac implants and other biocompatible materials placed in the blood stream. We have used implanted silver ions near the surface of GPC to completely inhibit cell attachment and adhesion. Cells attach and strongly adhere to areas close to the silver implanted surfaces. Patterned ion implantation permits precise control of tissue growth on GPC and other biocompatible substrates. Cell growth limited to micrometric patterns on a substrate may be useful for in vitro studies of associated biological processes in an otherwise identical environment. The patterned inhibition of cell attachment persists for periods of time significant relative to typical implant lifetimes.
Nanofabrication Based on Ion Beam-Laser Interactions with Self-Assembly of Nanoparticles
Authors: Kishimoto Naoki , Saito K. , Pan Jin , Wang H. , Takeda Y. 
Published: April 2011

AbstractIon beam-based techniques offer various possibilities for robust spatial control of nanoparticles. Since ion implantation is inherently good at depth control of solutes or nanoparticles, additional lateral control may lead to 3D control of nanoparticles. We pursue a lateral-control method of nanoparticle assembly by controlling photon-energy field under ion implantation. Laser is irradiated into a-SiO2, either sequentially or simultaneously with ion implantation. Ions of 60 keV Cu- or 3 MeV Cu2+and photons of 532 nm are used to study effects on nanoparticle evolution. Simultaneous laser irradiation under ion implantation enhances surface plasmon resonance (SPR), i.e., nanoparticle precipitation, while sequential laser irradiation of 532 nm tends to cause a decay of SPR, i.e., dissolution of Cu nanoparticles. The energy-field perturbation of laser, interactive with nanoparticle evolution, can be used for controlling nanoparticle assembly.
In-Situ Studies on Stoichiometry and Structure of Thin Film Yttria-Stabilized Zirconia under Thermal Processing
Authors: Chang C.L. , Shutthanandan V. , Singhal S. C. , Ramanathan Shriram 
Published: April 2011

AbstractThin films of 8 mol% yttria-stabilized zirconia (YSZ) of thickness ranging from 15nm-500nm have been deposited on Si3N4(90nm)/Si substrates by RF sputtering at room temperature. These samples have been studied using in situ ion scattering techniques including Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA) to analyze the oxygen distribution and defect chemistry as a function of annealing in various oxidizing and reducing ambient upto 500°C. In addition, the structural quality of these films after long time annealing has been investigated using grazing incidence X-ray diffraction (GIXRD). Temperature dependent X-ray absorption spectroscopy (XAS) has been performed to study the unoccupied density of states and chemical nature of YSZ. In this paper, we will discuss in detail the effects of annealing in different ambient on the defect chemistry, structure and stability of films in these materials systems.
Doped Nanocrystalline Pt-Promoted Ceria-Zirconia as Anode Catalysts for IT SOFC: Synthesis and Properties
Authors: Sadykov Vladislav , Mezentseva Natalia , Alikina Galina , Lukashevich Anton , Muzykantov Vitalii , Bunina Rimma , Boronin Andrei , Pazhetnov Egor , Paukshtis Eugenii , Kriventsov Vladimir , Smirnova Alevtina , Vasylyev Oleksandr , Irvine John , Bobrenok Oleg , Voronin Vladimir , Berger Ivan 
Published: April 2011

AbstractCeria-zirconia samples doped with Gd, Pr, Sm, or La cations were prepared via Pechini route and promoted by Pt. Effect of their real structure and surface properties (characterized by neutronography, EXAFS, XPS, FTIRS of adsorbed CO) on the mobility and reactivity of the lattice oxygen (by oxygen isotope exchange and CH4 TPR) was analyzed. For the reaction of CH4 steam reforming (SR), catalytic performance is determined both by Pt dispersion and lattice oxygen mobility. Ni-YSZ anodes promoted by these catalysts possess a stable and efficient performance in CH4 SR in the 600-800°C range in stoichiometric feeds without coking.
Establishment of Reaction Phase Diagrams of Pseudo Quaternary Li-Ni-Co-Ti Oxides Library
Authors: Fujimoto Kenjiro , Onoda Kazuhiro , Ito Shigeru 
Published: April 2011

AbstractReaction phase diagram of pseudo four-components Li-Ni-Co-Ti oxides was established for finding new chemical composition and functional materials by the combinatorial high-throughput preparation system “M-ist Combi,” based on electrostatic spray deposition process and the combinatorial x-ray powder diffraction apparatus. The new layered-type compounds were found wider composition region than the previous reported composition region of LiNi0.8-yCo0.2TiyO2 (0≤y≤0.1). Furthermore, the new composition regions of single phase for spinel-type and rock salt-type compounds in pseudo four-components Li-Ni-Co-Ti oxides system were also found in a short time.
Combinatorial Approach for Thermoelectric Materials through Bulk Composition-Spreads and Diffusion Multiples
Authors: Yamamoto Atsushi , Noguchi Teruo , Obara Haruhiko , Ueno Kazuo , Ikeuchi Satoaki , Sugawara Tooru , Shimada Kenji , Takasaki Youichi , Ishii Yoshikazu 
Published: April 2011

AbstractIn this paper we describe a new attempt of high-throughput screening of thermoelectric materials by combining the use of the “bulk composition-spread (CS)” or “bulk diffusion multiples (DM)” and the “scanning thermal probe microanalyzer (STPM).” The (Bi2Te3)1-x(Sb2Te3)x (0<x<1) and Ni1-xCux (0<x<1) bulk CS samples were prepared by conventional powder metallurgy method by using mechanical alloying and spark plasma sintering process. The Ni-Cu-X (X=Sn, In, Bi.) DM sample was prepared by post-heating of the CS samples in a molten metal. The two dimensional distributions of Seebeck coefficient and the thermal conductivity of the cross section of the CS and DM samples which composed of graded composition were visualized by using STPM at room temperature. The composition variation was checked by EDX. The relationship between composition and the thermoelectric properties was successfully determined by using the mapping results. The time required for mapping out the 100x100 pixel image was 8 to 11 hours. The total time required for this set of the screening experiment, from sample preparation to the final conclusion, was within 24 hours. For samples Ni-Cu-X DM the diffusion length of the elements at the interface can be large as 1mm and it was found that STPM is applicable to visualize the thermoelectric properties at the region of interest.
Basic Research on Combinatorial Evaluation Method for Coefficient of Thermal Expansion
Authors: Aono Yuko , Hata Seiichi , Sakurai Junpei , Yamauchi Ryusuke , Tachikawa Hiroyuki , Shimokohbe Akira 
Published: April 2011

AbstractThe coefficient of thermal expansion (CTE) is one of the most important material properties for actuators driven by heat or structure over a wide temperature. The CTE of an alloy depends on its composition, and combinatorial methods are very effective for researching new alloys. A CTE evaluation method, which can be applied to combinatorial methods or a thin film library, is proposed in this paper. The thermal behavior of a bi-layer cantilever couple was used for the evaluation, and the Young's modulus, which is also an important property, was simultaneously obtained. Firstly, one bi-layer cantilever was fabricated and agreement of the thermal behavior with the theoretical behavior was confirmed. The estimated error of the measurement device (CCD camera) resolution was then analyzed. The results indicate that combinatorial evaluation does not enable an accurate evaluation of Young's modulus, but does allow the CTE be accurately determined.
Determination of strain within Si1-yCy layers grown by CVD on a Si Substrate
Authors: Cherkashin Nikolay , Gouye A. , Hue F. , Houdellier F. , Hytch M. J. , Snoeck E. , Paillard V. , Kermarrec O. , Rouchon D. , Burdin M. , Holliger P. , Claverie A. 
Published: April 2011

AbstractIn this work, we performed quantitative measurements of strain in structures consisting of a 30 nm-thick Si1-yCy layer grown by chemical vapour deposition (CVD) on a Si (001) substrate at 550 or 600°C. The total C concentration varies from 0.67 to 1.97% that was measured by SIMS. Geometric phase analysis (GPA) of high resolution transmission electron microscopy (HR TEM) cross-section images and convergent beam electron diffraction (CBED) were used to deduce the strain within these Si1-yCy layers. Finite-element simulations were carried out to estimate the impact of strain relaxation in thin areas of a specimen. These results were compared with the data obtained by high resolution X-ray diffraction and Raman spectroscopy and with the predictions of elasticity theory. Particular interest is paid to the formation of the structural defects within Si1-yCy layers as a function of a C concentration, growth temperature and incorporated strain. Both cross-sectional and plan-view TEM specimen configurations were used to obtain quantitative information on the defect size distribution, their density and structure.
Aberration-corrected HRTEM of the Incommensurate Misfit Layer Compound (PbS)1.14NbS2
Authors: Garbrecht Magnus , Spiecker Erdmann , Jäger Wolfgang , Tillmann Karsten 
Published: April 2011

AbstractThe development of tunable spherical aberration (Cs) imaging correctors for medium-voltage transmission electron microscopes (TEM) offers new opportunities for atomic-scale in-vestigations of materials. A very interesting class of microstructures regarding a variety of dif-ferent physical properties are the transition metal dichalcogenide misfit layer compounds exhibit-ing a high density of incommensurate interfaces due to their stacked nature. In the present study, the benefits coming along with the set-up of negative CSimaging (NCSI) conditions (in TEM) are demonstrated by means of different examples regarding local inhomogeneities in (PbS)1.14NbS2crystals that can not be dissected in such detail by averaging x-ray techniques.
TEM and STEM study of the Au nano-particles supported on metal oxides
Authors: Akita Tomoki , Tanaka Koji , Kohyama Masanori , Haruta Masatake 
Published: April 2011

AbstractThe Au nano-particles are deposited on the metal oxide substrate, TiO2 and CeO2, and the structure of the Au particles and Au-metal oxide interface was observed by TEM and HAADF-STEM. It was found that the growth of Au particles on TiO2 and CeO2 by heating treatment is suppressed in the reductive atmosphere. The HAADF-STEM observation was carried out and the atomically resolved HAADF-STEM images in profile-view are successfully obtained for Au/TiO2 and Au/CeO2 samples. The Au particles tend to supported on CeO2 surface with the flat interface compared to the TiO2 substrate. The incoherent interface is observed for the Au particles-CeO2 interface.
Study of Elastic Behavior of Metallic Thin Films by 2D Synchrotron XRD and in situ Tensile Testing
Authors: Guillaume Geandier , Pierre-Olivier Renault , Philippe Goudeau , Le Bourhis Eric , Baptiste Girault 
Published: April 2011

AbstractUnderstanding the mechanical behaviour of nano-structured thin films in relation to their structure, in particular to the grain size, is of high importance for the development of technological applications. Model nanometric multilayer W/Au systems exhibiting different structures are elaborated. These films are supported by a (thin) polyimide substrate. Films mechanical response is characterized experimentally by tensile tests carried out in-situ in a X-ray diffractometer installed on a synchrotron source. X-ray diffraction in transmission geometry has been used to study the deformations of both phases as a function of applied load. This geometry has been developed in the aim of optimizing the experiment time.
Electronic Structures of Dyes and Phthalocyanines Estimated with “Photo-Electron Spectroscopy in Air (PESA)”
Authors: Nakajima Yoshiyuki , Yamashita D. , Ishizaki A. , Pellissier B. , Uda M. 
Published: April 2011

AbstractThe near-edge electronic structures of several dyes and phtalocyanines were investigated using Photo-Electron Spectroscopy in Air (PESA). The ionization potentials (IPs) of N3, N719, Z907, D102, D149 and D205 were derived from observed photoemission threshold energies to be 5.88, 5.47, 5.44, 5.53, 5.44 and 5.49eV, respectively. Density of states (DOS) of Fe-, Ni-, Cu- and H2-phthalocyanines were deduced from differentiation of observed photoemission yields with incident photon energies. DOS thus obtained were well compared with calculated ones estimated with use of the DV-Xα molecular orbital calculation method.
Photoemission Investigation of the Energy Level Alignment at the Rubrene/metal Interface
Authors: Ding Huanjun , Gao Yongli 
Published: April 2011

AbstractThe electronic structure of the interfaces between rubrene and various metals, including Au, Ag, Al, and Ca, have been investigated with photoemission and inverse photoemission spectroscopy. The formation of the interface dipole is observed at all interfaces. The Fermi level shifts linearly within the band gap as a function of metal workfunction, until it is pinned at the lowest unoccupied molecular orbital (LUMO) by Ca. Strong interactions take place at the interface between rubrene and Ca, evidenced by the evolution of the valence features.
Improving Stability of Pentacene Field-Effect Transistors with Post-Annealing
Authors: Liu Shun-Wei , Huang Jia-Cing , Lee Chih-Chien , Lee Chin-Ti , Wang Juen-Kai 
Published: April 2011

AbstractIn this report, we demonstrate that the performance and stability of pentacene top-contact field-effect transistor can be greatly improved with post-annealing treatment. After post-annealing at 90°C for 12 hours in nitrogen environment, the hole field-effect mobility of 0.3 cm2/Vs and the on/off current ratio of 107 were achieved, demonstrating 100% improvement in performance after the post-annealing treatment. The decay rate of drain current at constant gate and drain-source voltage was found to be decreased by more than 40%. The improved performance is attributed to the elimination of trapped holes and lattice defects in the organic semiconductor layer due to the post-annealing process.
Ion Beam Deposition from Colloidal CdSe/ZnS Nanocrystals Solutions for Fabricating Electroluminescent Device
Authors: Tani Yuki , Kobayashi Satoshi , Kawazoe Hiroshi 
Published: April 2011

AbstractWe have already reported AC-drive CdSe/ZnS quantum dot (QD) inorganic electroluminescent (EL) devices from colloidal solution. The EL spectra of the devices reproduced photoluminescent spectra of the source QD solutions. Furthermore, the observation of time resolved luminescent properties in ambient atmosphere at room temperature, are analyzed for improvements and projection of brightness and efficiency. The results suggest that the lifetimes of excited states in quantum dots are affected by the electric field in the electroluminescent devices.
Efficient Thin Polymer Solar Cells with Post-Annealing
Authors: Liu Shun-Wei , Lee Chih-Chien , Huang Ping-Tsung , Chen Chin-Ti , Wang Juen-Kai 
Published: April 2011

AbstractThe authors report the study of the dependence of the device performance of polymer solar cells based on single 50-nm heterojunction poly(3-hexylthiophene)/[6,6]-phenyl-C61-butyric acid methylester (P3HT/PCBM) layer on annealing process. Annealing before and after cathode deposition were performed for comparison. In the case of post-annealing at 150¢XC for 60 min., the device attains a conversion efficiency of 4.9%, a fill factor of 53 %, and an open-circuit voltage of 0.67 V. These values are comparable with the highest values reported previously. The annealing process is expected to modify the network morphology of the P3HT/PCBM layer. This study demonstrates that it is possible to attain good solar cell performance with the combination of single thin active layer and post-annealing treatment. This may open up an opportunity to fabricate tandem polymer solar cells.
Magnetometric Measurements of Ferro- or Ferrimagnetic Microparticles Dispersed in Medium Approximating the Intracellular Environment
Authors: Jurdak Peter , Kopani Martin , Šimacek Ivan , Manka Jan , Škrátek Martin 
Published: April 2011

AbstractRelaxation of the remanent magnetization produced by samples with magnetized ferromagnetic micro-particles dispersed in a liquid non-ferromagnetic material was measured. The intracellular environment was simulated by liquid with two various viscosities. Using the SQUID gradiometric system the time-dependences of the relaxation on the intensity of the magnetizing field and the viscosity of non-magnetic carrier liquid have been investigated. Since the relaxation is always present after the magnetizing process, the time-dependences of the relaxation has to be measured for the correction of resulting data in the realistic evaluation of the ferromagnetic contamination of retained dust in the lungs (magnetopneumography), in the magnetic measurement of human iron stores in the liver and it can be also successfully applied in a magnetopneumographic investigation of alveolar clearance.