bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanoindentation Characterization of PECVD Silicon Nitride on Silicon Subjected to Mechanical Fatigue Loading
Authors: Huang Z-K , Ou K-S , Chen K-S 
Published: September 2011

ABSTRACTIn this work, the mechanical properties of PECVD silicon nitride deposited on silicon substrates by two different processing conditions were investigated. Indentation method was primary used for qualitatively examining the effect of process conditions to the achieved mechanical properties. The experimental results indicated that the residual stress, fracture toughness and interfacial strength, as well as the fatigue crack propagation were strongly depended on the processing conditions such as deposition temperatures and chamber pressures. Preliminary results indicated that the specimen deposited at a lower temperature and a lower pressure exhibited a much less residual tensile stress and a better interface strength. On the other hand, it was found that RTA could enhance the interfacial strength but the generated high tensile strength could actually reduce the equivalent toughness and leads to structural reliability concerns. In summary, the characterization results should be possible to provide useful information for correlating the mechanical reliability with the processing parameters for future structural design optimization and for improving the structural integrity of PECVD silicon nitride films for MEMS and IC fabrication.
On the carbo-thermal reduction of silica for carbon nano-fibre formation via CVD
Authors: Bachmatiuk Alicja , Börrnert Felix , Ibrahim Imad , Büchner Bernd , Rümmeli Mark H. 
Published: September 2011

ABSTRACTThe formation of carbon nanostructures using silica nanoparticles from quartz substrates as a catalyst in an aerosol assisted chemical vapor deposition process was examined. The silica particles are reduced to silicon carbide via a carbothermal reduction process. The recyclability of the explored quartz substrates is also presented. The addition of triethyl borate improves the efficiency of the carbothermal reduction process and carbon nanotubes formation. Moreover, the addition of hydrogen during the chemical vapor deposition leads to the helical carbon nanostructures formation.
Hole or Electron Doped C60Polymer Using Free Electron Laser Irradiation
Authors: Iwata Nobuyuki , Koide Daiki , Katou Syouta , Ikeda Eri , Yamamoto Hiroshi 
Published: September 2011

ABSTRACTPolymerized C60 crystals were grown using the free electron laser (FEL) irradiation. In order to promote the polymerization degree, hole or electron was doped in the C60 crystals grown by the liquid-liquid interfacial precipitation (LLIP) method to eliminate the degradation by oxidation. The specimen grown with the I2 dissolved butylalcohol (BTA, CH3(CH2)3OH) and the C60 saturationo-xylene solution, subsequently pressed at 7GPa, showed only Ag(2)-derived mode at 1456 cm-1 after the FEL irradiation. The specimen belonged to so-calledFphase, which is not obtained by the typical photo-induced polymerization process. It was noted that the FEL irradiation for polymerization of C60 was quite useful.
Comparison of Epitaxial Graphene on Si-face and C-face 6H-SiC
Authors: Mou Shin , Boeckl J. J. , Grazulis L. , Claflin B. , Lu Weijie , Park J. H. , Mitchel W. C. 
Published: September 2011

ABSTRACTWe present atomic force microscopy (AFM), Hall-effect measurement, and Raman spectroscopy results from graphene films on 6H-SiC (0001) and (000-1) faces (Si-face and C-face, respectively) produced by radiative heating in a high vacuum furnace chamber through thermal decomposition. We observe that the formation of graphene on the two faces of SiC is different in terms of the surface morphology, graphene thickness, Hall mobility, and Raman spectra. In general, graphene films on the SiC C-face are thicker with higher mobilities than those grown on the Si-face.
Growth of diameter-modulated single-walled carbon nanotubes through instant temperature modulation in laser-assisted chemical vapor deposition
Authors: Mahjouri-Samani M. , Zhou Y. S. , Xiong W. , Gao Y. , Mitchell M. , Lu Y. F. 
Published: September 2011

ABSTRACTThe diameter of individual single-walled carbon nanotubes (SWNTs) was successfully modulated along their axes by instant temperature control in a laser-assisted chemical vapor deposition (LCVD) process. SWNTs were grown using different temperature profiles to investigate the effects of temperature variation on their growth. Due to the inverse relationship between SWNT diameter and growth temperature, SWNTs with ascending diameters were obtained by reducing the LCVD temperature from high to low. The diameter-modulated SWNTs were grown across a pair of Mo electrodes to form field-effect transistors (FETs) for investigation of their electronic transport properties. Fabricated devices demonstrated properties similar to Schottky diodes, implying different bandgap structures at the ends of the SWNTs. Raman spectroscopy, transmission electron microscopy, and electronic transport characteristics were studied to investigate the influence of temperature variation on the structural and electronic characteristics of SWNTs.
Thermal, Chemical and Radiation Treatment Influence on Hydrogen Adsorption Capability in Single Wall Carbon Nanotubes
Authors: Obolensky Michail , Kravchenko Andrew , Beletsky Vladimir , Petrusenko Yuri , Borysenko Valeriy , Lavrynenko Sergey , Basteev Andrew , Bazyma Leonid 
Published: September 2011

ABSTRACTThe raw single wall carbon nanotubes (SWCNT) were chemically and thermally treated and then milled in ball mill. After this SWCNT were irradiated by electron beam with energy 2.3 MeV up to fluence 1014 e-/cm2 at room temperature. Then SWCNT were saturated with hydrogen at pressure 5 bar and quenching down to the temperature 78 K. The sorption capability was measured by means of mass-spectroscopy and volumetric methods. The double increasing of mass hydrogen content in electron bombarded SWCNT was showed comparatively with non-irradiated samples.
Residual Stress in Sputtered Silicon Oxycarbide Thin Films
Authors: Du Ping , Lin I-Kuan , Yan Yunfei , Zhang Xin 
Published: September 2011

ABSTRACTSilicon carbide (SiC) has received increasing attention on the integration of microelectro-mechanical system (MEMS) due to its excellent mechanical and chemical stability at elevated temperatures. However, the deposition process of SiC thin films tends to induce relative large residual stress. In this work, the relative low stress material silicon oxide was added into SiC by RF magnetron co-sputtering to form silicon oxycarbide (SiOC) composite films. The composition of the films was characterized by Energy dispersive X-ray (EDX) analysis. The Young’s modulus and hardness of the films were measured by nanoindentation technique. The influence of oxygen/carbon ratio and rapid thermal annealing (RTA) temperature on the residual stress of the composite films was investigated by film-substrate curvature measurement using the Stoney’s equation. By choosing the appropriate composition and post processing, a film with relative low residual stress could be obtained.
Poly Lactic-Co-Glycolic Acid Carbon Nanofiber Composite for Enhancing Cardiomyocyte Function
Authors: Stout David A. , Yoo Jennie , Webster Thomas J. 
Published: September 2011

ABSTRACTThe objective of the present in vitro research was to determine cardiomyocyte function on poly lactic-co-glycolic acid (50:50 (PLA:PGA); PLGA) with greater amounts of carbon nanofibers (CNFs) and variations in CNF size, for myocardial tissue engineering applications. The addition of CNFs would increase conductivity and strength of pure PLGA. For this reason, different PLGA: CNF ratios (100:0, 75:25, 50:50, 25:75, 0:100 wt.%) were created and conductivity and cytocompatibility properties with human cardiomyocytes were determined. Results showed that PLGA:CNF materials were conductive and that conductivity increased with greater amounts of PLGA added, from 0 S.m-1 for 100:0 wt.% (pure PLGA) to 5.5x10-3 S.m-1 for 0:100 wt.% (pure CNFs) material. Furthermore, results indicated that cardiomyocyte density increased with greater amounts of CNFs of 200nm in diameter in PLGA (up to 25:75 wt.% , PLGA:CNFs). This study, thus, provided an alternative conductive scaffold using nanotechnology which should be further explored for cardiovascular applications.
Vesicular Lipid Nanoparticles (Liposomes) for the Treatment of Medical Device Infections
Authors: Taylor Erik , Kaviratna Anubhav , Banerjee Rinti , Webster Thomas J. 
Published: September 2011

AbstractLiposomes (a phospholipid bi-layer which can be formulated to contain drugs or other reagents) composed of endogenous phospholipid dipalmitoylphosphatidylcholine (DPPC) in combination with dioleoylphosphatidylethanolamine (DOPE), lauric acid, and silver sulfadiazine were made into vesicular nanoparticles in this study using an optimized extrusion technique. Liposomes were then tested for antibacterial activity against a range of bacteria species including Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Bacillus subtilis (all are relevant human pathogens known to infect implants) and were also challenged to prevent the growth of adherent biofilms (a robust slimy extracellular matrix) through an in vitro assay relevant to device related infections. It was found that all liposomes reduced bacterial growth, and, most importantly, liposomes containing DPPC and DOPE reduced biofilm formation better than the commercially available antibiotic silver sulfadiazine. These results indicated for the first time that such liposomes might be a better approach to prevent device related infections.
Antibacterial zinc oxide nanoparticles in polymer biomaterial composites
Authors: Seil Justin T. , Webster Thomas J. 
Published: September 2011

ABSTRACTParticulate zinc oxide (ZnO) is a known antibacterial agent. Studies have shown that reducing the size of ZnO particles to nanoscale dimensions further enhances their antibacterial properties. Polymers, like all biomaterials, run the risk of harboring bacteria which may produce an antibiotic-resistant biofilm. The addition of ZnO nanoparticles, to form a composite material, may reduce undesirable bacteria activity. The purpose of the present in vitro study was to investigate the antibacterial properties of ZnO nanoparticles when incorporated into a polymer biomaterial. Staphylococcus aureus were seeded at a known cell density onto coverslips coated in a film of polyvinyl chloride (PVC) with varying concentrations of ZnO nanoparticles. Samples were cultured for 24 or 72 h. Methods of analysis, including optical density readings and crystal violet staining, indicated a reduced presence of biofilm on ZnO nanoparticle and polymer composites compared to polymer control. Live/dead assays provided images to confirm reduced presence of active bacteria on samples with zinc oxide nanoparticles. Development of this technology may improve biomaterial effectiveness for applications, such as endotracheal tubes and implanted biomaterials, which are prone to bacterial infection.
A Picowatt Energy Harvester
Authors: Evans Joe , Smits Johannes , Montross Carl , Salazar Gerald 
Published: September 2011

ABSTRACTThe authors describe an energy harvester circuit fabricated with integrated thin ferroelectric film capacitors on a silicon substrate. The harvesting mechanism is a folded double-beam cantilever with proof masses at both end points. Interdigitated electrode capacitors are located at the three points on the folded cantilever that are expected to experience maximum bending moment and should produce up to 5V as a function of external vibration. The die has the dimensions of 1.6mm on a side and is designed to be mounted in a TO-18 package transistor-style package. Due to its small size, the self-contained piezoelectric MEMs device should produce 50 picowatts in a 1g vibration environment while occupying little space.
Structure Control of Bioactive Titanate Nanomesh Layers Fabricated on Laser Irradiated Ti-based Bulk Metallic Glass using Hydrothermal-Electrochemical Method
Authors: Maruyama Sayaka , Sugiyama Naota , Yoshimura Masahiro , Shinonaga Togo , Tsukamoto Masahiro , Abe Nobuyuki , Wada Takeshi , Wang Xinmin , Inoue Akihisa , Okada Kiyoshi , Matsushita Nobuhiro 
Published: September 2011

ABSTRACTThe surface of Ti-based bulk metallic glass (BMG) was irradiated by the femto-second laser and microgrooves were formed on the surface. The titanate nanomesh layers were fabricated on the micro-grooved BMG surface by hydrothermal-electrochemical (H-E) treatment changing the conditions of the concentration of electrolyte solution (0 and 5 M) and applying current density (0-200 mA/cm2). The bone-inducing capacity of the samples with different H-E treatment was confirmed by soaking them in a simulated body fluid for 12 days. The H-E treatment in higher concentration 5 M NaOH aq. and applying higher current density above 0.5 mA/cm2exhibited excellent bioactivity inducing large hydroxyapatite crystallites.
Laser Treatment of Organic Thin Film Solar Cells
Authors: Clair Maurice , Scholz Christian , Keiper Bernd , Haenel Jens 
Published: September 2011

ABSTRACTIn the last years more and more effort has been put into the development of thin-film organic solar cells using conductive and semi-conductive polymers. A great advantage of these polymers is the possibility to deposit them in high throughput print and coating processes. This feature provides huge potential for future production of low cost photovoltaics. While TCO layers form the transparent front contact, polymers are used for the buildup of the active layer and the design of the interface between active layer and front contact. The polymer materials have to be patterned in order to allow for a row connection of the solar cell work (typically by structured deposition, e.g. printing). In addition the bulk hetero junction (BHJ) of the active layer consisting of poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) requires an annealing step to optimize the layers structure and therewith the efficiency of the solar cell (typically by thermal treatment, e.g. oven). 3D-Micromac used ultra-short pulsed lasers to evaluate the applicability of various wavelengths for the selective ablation of the BHJ consisting of P3HT:PCBM on top of a Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and indium tin oxide (ITO) film system on glass substrates. The process of laser annealing was investigated using a short-pulsed laser with a wavelength close to the absorption maxima of the BHJ.
Fe-42%Ni austenitic alloy as a novel substrate for flexible electronics
Authors: Ma Xiaoxiao , Khan Shahrukh A. , Choi Nackbong , Hatalis Miltiadis , Robinson Mark 
Published: September 2011

ABSTRACTWe report Fe-42%Ni as a novel high-performance substrate for a-IGZO TFT fabrication after evaluating 8 different metals for chemical compatibility, mechanical flexing and dimensional stability. Excellent flexibility and rollability indicates that Fe-42%Ni would be a good choice as flexible substrate for R2R process. Pre-annealing process for stabilizing the substrate is studied and applied to the Fe-42%Ni foil before TFT fabrication. Staggered bottom gate a-IGZO TFTs which were fabricated on this substrate have field effect mobility of 12 cm2/V.s, threshold voltage of 2V, sub-threshold swing of 0.6V/decade and on/off current ratio exceeding 107.
Size Dependent Particle Toxicity in Drosophila
Authors: Gorth Deborah J , Rand David M , Webster Thomas J 
Published: September 2011

ABSTRACTNanotechnology, or the use of materials with one dimension less than 100nm, offers the ability to change particle reactivity by simply changing their size. This novel property of nanomaterials is used to create more effective medical treatments for cancer, tissue engineering and regenerative medicine, but the influence of nanoparticle size on environmental toxicity has not been thoroughly addressed to date. This study examines the influence of the size of silver particles on drosophila egg development by exposing their eggs to particle concentrations ranging from 10ppm-100 ppm of silver. Size, chemistry and agglomeration of the silver particles are evaluated using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS). This analysis confirmes individual silver particle size in the ranges of 20-30nm, 100nm and 500-1,200 nm with similar chemistry. DLS and TEM data also indicates agglomeration in water; with the TEM images showing individual particles in the correct size range, but the DLS z-average sizes of the silver nanoparticle are 782 ± 379 nm for the 20-30nm silver nanoparticles, 693 ± 114 nm for the 100nm silver nanoparticles and 508 ± 32 nm for the 500-1,200nm silver particles. Most importantly, here we show significantly more drosophila egg toxicity when exposed to larger, non-nanometer, silver particles. Upon exposure to silver nanoparticles sized 20-30nm, drosophila eggs do not exhibit a statistically significant (p<0.05) decrease in their likelihood to pupate, but eggs exposed to larger silver particles (500-1,200nm) are 91% (±18%) less likely to pupate. Exposure to silver nanoparticles reduces the percentage of pupa able to emerge as adults. At 10ppm of silver particle exposure, only 57% (± 48) of the pupa exposed to 20-30nm silver particles become adults whereas 89% (±25) of the control group becoem adults and 94%(±52) and 91%(±19) of the 500-1,200nm and 100nm group, respectively, reached adulthood. In this manner, this paper provides evidence that nanoscale silver particles (<100nm) are less toxic to drosophila eggs than conventional (>100nm) sized silver particles.
Refractive Index memory effect of ferroelectric materials by domain control
Authors: INOUE Kazuhiko , MORITA Takeshi 
Published: September 2011

ABSTRACTFerroelectric electro-optics materials are widely studied for optical applications, such as optical switches, optical scanners, and optical shutters. However, conventional operation of those devices requires a continuous external electrical field. On the other hand, our group proposes an optical property memory effect by controlling domain structure as either full-polarized or depolarized state using asymmetric voltage operation. The optical property memory effect can keep its optical value, such as refractive index and light transmittance without any external electrical field. In this study, it was confirmed that the refractive index state had two stable values depending on domain conditions. This memory effect should be useful for innovative optical switch or scanner in the future.
Ionization of decaborane with controlled hydrogen content by charge transfer from ambient gas
Authors: Ohishi Yuji , Kimura Kaoru , Yamaguchi Masaaki , Uchida Noriyuki , Kanayama Toshihiko 
Published: September 2011

ABSTRACTWe present the ionization of decaborane (B10H14) and formation of hydrogen- and boron-contents-controlled B10-yHx+ through the charge transfer from ambient gas ion to decaborane molecules in an external quadrupole static attraction ion trap. The charge transfer energy is estimated from the experimentally observed products. PBE0/6-311+G(d)//B3LYP/6-31G(d) level of DFT calculations are conducted to investigate the mechanism of charge transfer from ambient gas ion. The calculation of the difference of ionization energies and mismatch of orbital energies between decaborane and ambient gas reveals the mechanism of ionization.
Ionic mobility in Nasicon-type LiMIV2(PO4)3 materials followed by 7Li NMR spectroscopy.
Authors: Arbi K. , Sobrados I. , Hoelzel M. , Kuhn A. , Garcia-Alvarado F. , Sanz J. 
Published: September 2011

AbstractLithium mobility in LiM2(PO4)3 compounds, with M= Ge, Ti, Sn, Zr and Hf, has been investigated by 7Li Nuclear Magnetic Resonance (NMR) spectroscopy in the temperature range 100-500 K. From the analysis of 7Li NMR quadrupole interactions (CQ and η parameters), Li sites occupancy and exchange processes between structural sites have been studied. Below 250K, Li ions are preferentially located at M1 sites in rhombohedral phases, but occupy M12 sites in triclinic ones. At increasing temperatures, Li mobility has been deduced from spin-spin () and spin-lattice relaxation () rates. In this analysis, the presence of two relaxation mechanisms in plots has been associated with departures of conductivity from the Arrhenius behavior. At high temperatures, residence times at M12−T11−T11−T1 and M12 sites become similar and conductivity significantly increase. This superionic state can be achieved by enlarged order-disorder transformations in rhombohedral phases, or by sharp first order transitions in triclinic ones. Results described in the LiTi2(PO4)3 sample have been compared with those obtained in rhombohedral Li1+xTi2-xAlx(PO4)3 and LiTi2-xZrx(PO4)3 series showing respectively higher and lower conductivities. In the case of Li1.2Ti1.8Al0.2(PO4)3, displaying the highest reported conductivity, NMR results are discussed in relation with those obtained by Neutron Diffraction (ND) and Impedance Spectroscopy (IS). Diffusion coefficients determined by NMR Pulse Field Gradient (PFG) technique are similar to those deduced from Impedance Spectroscopy and NMR relaxation data.
New Insight into Electrochemical Differences in Cycling Behaviors of a Lithium-ion Battery Cell Between the Ethylene Carbonate- and Propylene Carbonate-Based Electrolytes
Authors: Tasaki Ken , Goldberg Alexander , Liang Jian-Jie , Winter Martin 
Published: September 2011

ABSTRACTDensity functional theory (DFT) calculations and classical molecular dynamics (MD) simulations have been performed to gain insight into the difference in cycling behaviors between the ethylene carbonate (EC)-based and the propylene carbonate (PC)-based electrolytes in lithium-ion battery cells. DFT calculations for the ternary graphite intercalation compounds (Li+(S)iCn: S=EC or PC), in which the solvated lithium ion Li+(S)i (i=1~3) was inserted into a graphite cell, suggested that Li+(EC)iCn was more stable than Li+(PC)iCn in general. Furthermore, Li+(PC)3Cn was found to be energetically unfavorable, while Li+(PC)2Cn was stable, relative to their corresponding Li+(PC)i in the bulk electrolyte. The calculations also revealed severe structural distortions of the PC molecule in Li+(PC)3Cn, suggesting a rapid kinetic effect on PC decomposition reactions, as compared to decompositions of EC. In addition, MD simulations were carried out to examine the solvation structures at a high salt concentration: 2.45 mo kg-1. The results showed that the solvation structure was significantly interrupted by the counter anions, having a smaller solvation number than that at a lower salt concentration (0.83 mol kg-1). We propose that at high salt concentrations, the lithium desolvation may be facilitated due to the increased contact ion pairs, so that a stable ternary GIC with less solvent molecules can be formed without the destruction of graphite particles, followed by solid-electrolyte-interface film formation reactions. The results from both DFT calculations and MD simulations are consistent with the recent experimental observations.