bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of various annealing temperature on carbon nanotubes for N2 detection
Authors: Huang Chien-Sheng , Huang Bohr-Ran , Jang Yung-Huang , Hsieh Chih-Fu , Wu Chia-Ching , Chen Min-Chao , Yang Kun-Lin 
Published: April 2011

ABSTRACTThe vertically aligned carbon nanotubes (CNTs) deposited by microwave plasma-enhanced chemical vapor deposition (MPCVD) were utilized as resistive gas sensors.The carbon nanotubes were annealed between 200 to 800°C under N2 flow (500 sccm) for 15 minute, respectively. After that, the carbon nanotubes were exposed to an N2 filling and pumping environment. Upon exposure to N2 the electrical resistance of vertically aligned carbon nanotubes was found to increase. It was found that the N2 absorption of unannealed carbon nanotubes was reversible, whereas which of annealing ones was not. However, the sensitivity of the N2 absorption on carbon nanotubes was improved after annealing. From the Raman spectra, the ID/IG ratio of carbon nanotubes also decreased after annealing, indicating that more graphenes were formed by the annealing process. Furthermore, from X-ray photoelectron spectroscopy (XPS), it was observed that the ratio of the oxygen to carbon (O/C) signal intensity increased from 0.094 to 3.943 as the annealing temperature increased. As a consequence, it was suggested that the surface of carbon nanotubes was oxygenated and the absorption of N2 changed from physisorption to chemisorption.
Integration of microcatalysts on thin membrane for thermoelectric gas sensor devices
Authors: Choi Yeongsoo , Shin Woosuck , Tajima Kazuki , Izu Noriya , Matsubara Ichiro , Murayama Norimitsu 
Published: April 2011

ABSTRACTDispenser technique was employed to integrate the Pt loaded on alumina (Pt/alumina) micro-catalysts on thin membrane of micro-thermoelectric hydrogen sensor (μ-THS). The μ-THS with Pt loaded alumina showed higher sensing performance than bulk-type THS with Pt thin film prepared by RF sputtering method. For the μ-THS with Pt/alumina catalyst, its voltage signal was 7.3 mV for hydrogen concentration of 1 % in dry air at catalyst temperature of 100 °C. In the case of the bulk-type THS with Pt thin film catalysts, the voltage signal was 0.33 mV under the same condition.
High-Temperature SiC MOSFET Gas Sensors
Authors: Matocha Kevin , Tilak Vinayak , Sandvik Peter , Tucker Jesse 
Published: April 2011

ABSTRACTDue to tightening restrictions on combustion exhaust emissions, low-cost sensors are desired for monitoring NOx production in high-temperature exhaust streams. This paper reports the characterization of Silicon Carbide MOSFET NO sensors for use in combustion exhaust monitoring. SiC depletion-mode MOSFETs were fabricated using a thermally-grown silicon dioxide gate dielectric and a Pt catalytic metal gate electrode. SiC MOSFET gas sensors were characterized at temperatures as high as 525°C in an ambient of synthetic air and NO (50–200 ppm) for 30 hours with no degradation.
Pulse Shape Study of Chemical Vapor Deposited Diamond Alpha Particle Detectors
Authors: Wang S. G. , Sellin P. J. , Lohstroh A. , Özsan M. E. 
Published: April 2011

ABSTRACTWe report a study of pulse shapes of a radiation detector with a sandwich structure fabricated from chemical vapor deposited (CVD) polycrystalline diamond. The pulse shapes were recorded at room temperature using 5.486 MeV alpha particles from 241Am source. Only “fast” component was observed in the electron predominated pulses, whereas both “fast” and “slow” components were obtained in the hole predominated pulses, suggesting that electron charge drift is prompt and no detrapping occurred. In contrast, hole charge drift is slower than expected and trapping-detrapping took place during hole travel process.
Ferroelectric Thin Film Depositions for Various Types of FeRAMs (Ferroelectric Random Access Memories)
Authors: Fujisaki Yoshihisa , Ishiwara Hiroshi 
Published: April 2011

ABSTRACTFlash memories are now widely spread and conveniently used in mobile devices such as cellular phones, pagers, PDAs (Personal Digital Assistants), digital cameras and so on. And in the coming ubiquitous era, nonvolatile solid-state memories are expected to be more and more important for these mobile devices. However, Flash memories are not perfectly suitable for these mobile devices since their power consumptions are too high, writing speeds are two slow, programming endurances are limited up to 106 cycles. To resolve these problems, numbers of new nonvolatile solid-state memories are proposed and some of them are now under development. Among these newly emerging nonvolatile memories, FeRAMs (Ferroelectric Random Access Memories) are the only ones that are now in production. However, the process and materials to produce FeRAMs have not matured yet to support the ubiquitous technologies.In this study, we explore the process technologies and materials required for the future FeRAMs and obtained the result that the requirements can be satisfied by the known technologies at present.
Non-volatile Thin Film Transistors Using Ferroelectric/ITO Structures.
Authors: Tokumitsu Eisuke , Miyasako Takaaki , Senoo Masaru 
Published: April 2011

ABSTRACTWe report ferroelectric-gate thin film transistors (TFTs) using indium tin oxide (ITO) as a channel material. Bottom-gate structure TFTs have been fabricated using ferroelectric Pb(Zr, Ti)O3 (PZT) film as a gate insulator and ITO channel. Ferroelectric and ITO layers were formed by the sol-gel technique and RF sputtering, respectively. Drain current-drain voltage (ID-VD) characteristics of PZT/ITO ferroelectric-gate TFTs exhibit typical n-channel transistor operations with clear current saturation and electrical properties were improved by the post annealing. Drain current-gate voltage (ID-VG) characteristics demonstrate clear counterclockwise hysteresis loop due to the ferroelectric gate insulator. The obtained memory window is 2 V. The on/off current ratio of more than 102 has been obtained, which indicates that the ITO channel is sufficiently depleted by the ferroelectric polarization.
UV Assisted Rapid Thermal Processing of Strontium Bismuth Tantalate (SBT) Thin Films
Authors: O'Brien S. , Hurley P. K. , Crean G. M. , Johnson J. , Caputa C. , Wouters D. 
Published: April 2011

ABSTRACTA novel technique termed UV-assisted RTP has been developed and found to offer improvement in material properties, in particular when applied to thin films. Regarding crystallization of SBT, a number of UV-RTP strategies were developed and evaluated. It was demonstrated that UV irradiation of the sample material at a temperature in excess of the MOCVD deposition temperature was found to produce a significant increase in Pr.
Ge nanocrystals in MOS-memory structures produced by molecular-beam epitaxy and rapid-thermal processing
Authors: Nylandsted Larsen A. , Kanjilal A. , Lundsgaard Hansen J. , Gaiduk P. , Normand P. , Dimi-trakis P. , Tsoukalas D. , Cherkashin N. , Claverie A. 
Published: April 2011

ABSTRACTA method of forming a sheet of Ge nanocrystals in a SiO2layer based on molecular beam epitaxy (MBE) and rapid thermal processing (RTP) is presented. The method takes advantage of the very high precision by which a very thin Ge layer can be deposited by MBE. With proper choice of process parameters the nanocrystal size can be varied between ∼3 and ∼8 nm and the area-density between ∼1×1011and ∼1×1012dots/cm2. The tunneling oxide thickness is determined by the thickness of a thermally grown SiO2layer, and is typically 4 nm. C-V measurements of MOS capacitors reveal hole and electron injection from the substrate into the nanocrystals. Memory windows of about 0.2 and 0.5 V for gate-voltage sweeps of 3 and 6 V, respectively, are achieved.
Organic Memory Devices Using C60 and Insulating Polymer
Authors: Kanwal Alokik , Paul Shashi , Chhowalla Manish 
Published: April 2011

ABSTRACTIn this paper, we describe an all organic molecular memory device that combines the advantages of molecular and organic electronics. We accomplish this by combining C60 molecules with poly(4-vinylphenol) (PVP) and co-dissolving them in iso-propanol. The current-voltage measurements show a large hysteresis in the blend devices, in contrast to pure PVP devices. The thin blend films have been thoroughly characterized using Raman spectroscopy, atomic force microscopy and scanning electron microscopy.
Microwave dielectric properties of oriented BaLa4Ti4O15 ceramics fabricated by templated grain growth
Authors: Fukami Yuko , Wada Kensuke , Kakimoto Ken-ichi 
Published: April 2011

ABSTRACTDense and highly textured BaLa4Ti4O15 (BLT) ceramics was fabricated by templated grain growth method. Plate-like BLT particles prepared via a molten salt synthesis using NaCl flux were mixed with B LT powders obtained by the conventional solid state method. X-ray diffraction and scanning electron microscope studies of the textured ceramics showed plate-like BLT grains aligned parallel to the casting direction. Large anisotropy was found in the dielectric properties.
Evolution of Anisotropic Elastic Strains, and rf/Microwave Dielectric Properties of <110> Textured BST 60/40 Thin Films on <100> NdGaO3 Substrates
Authors: Simon W. K. , Akdogan E. K. , Bellotti J. A. , Safari A. 
Published: April 2011

ABSTRACTBa0.60Sr0.40TiO3 thin films were deposited on orthorhombic <100> oriented NdGaO3 substrates by pulsed-laser deposition. Film thickness ranged from 25 nm to 1200 nm. X-ray pole figures have shown consistent <110> textured films with good alignement to the substrate. X-ray strain analysis indicates up to 0.5% compressive strain along the (001) direction, and weaker tensile strain along (-110). Dislocation densities, as computed from strain data, were found to be in the range 5–6×105 cm-1 along both directions. The critical thickness for dislocation formation along (001) and (-110) were found to be 5 and 7 nm, respectively. Permittivity and tunability were investigated using interdigitated capacitors in the 45 MHz-20 GHz range. Dielectric properties and tunability in the <110> oriented films exhibited strong strain and directional properties. Tunability up to 54% was observed at moderate field levels (∼ 5 kV/mm).
MEMS SiGe Technologies for RF and Millimeterwave Communications
Authors: Busquére J. P. , Do N. , Bougriha F. , Pons P. , Grenier K. , Dubuc D. , Schumacher H. , Abele P. , Rydberg A. , Ojefors E. , Ancey P. , Bouche G. , Plana R. 
Published: April 2011

AbstractThis paper shows the potentialities of merging the MEMS and micromachining with SiGe technologies in order to speed up the performances of next generation of front end in term of flexibility, reconfigurability and adaptability. MEMS technologies are presented based on Benzo-Cyclo-Butene (BCB) materials and Bulk Acoustic Wave (BAW) materials. Special attention is paid to ensure a full compatibility between IC and MEMS. We have shown that very innovative functions could be considered by using this MEMSIC concept.
Nonlinear magneto-optics of nanogranular films
Authors: Kim Evgenia M. , Murzina Tatyana V , Aktsipetrov Oleg A , Kravets Anatolii F. 
Published: April 2011

ABSTRACTIn this paper, the results of experimental studies of magnetization-induced second- and third-order nonlinear optical effects in magnetic nanogranular films are described. Magnetization-induced variations of the intensity, polarization state and the phase of the harmonics' waves are observed in magnetic nanogranular films of the composition CoxAg1-x and Cox(Al2O3)1-x. Nonlinear magneto-optical Kerr effect (NOMOKE) in third-harmonic generation is observed in these nanomaterials. The second- and third-order NOMOKE from granular films is shown to exceed the linear magneto-optical Kerr effect by at least an order of magnitude.
Correlation of the Charge Storage and Magnetic Susceptibility of Hydrous RuO2
Authors: Swider-Lyons Karen E. , Bussmann Konrad M. 
Published: April 2011

ABSTRACTHydrous RuO2 is a mixed metallic-protonic conductor that is used as a charge storage material in electrochemical capacitors and as an electrocatalyst. Previous structural analysis by Dmowski, et. al. has shown that RuO2 is a composite of ordered RuO2 nanoparticles that are surrounded by hydrous grain boundaries. In this paper, magnetic susceptibility (MS) is used to show that the hydrous RuO2 has both localized and delocalized electrons. The localized electrons are attributed to Ru3+ defects that decrease in concentration with decreasing water content. The delocalized electrons are represented by a temperature independent paramagnetic (TIP) component of the MS. The magnetic data is consistent with a structure having metallic nanoparticles whose electrons become more itinerant with decreasing structural water. We conclude that hydrous RuO2 stores charge analogously to double-layer capacitors in which charge is stored at the interface of the hydrous grain boundaries and the metallic nanoparticles, and that there is effectively no difference in the charge storage mechanisms of hydrous RuO2 and carbon.
Improved composite electrode and lithium battery performance From smart use of the polymers and their properties
Authors: Gaudefroy Vincent , Guy Delphine , Lestriez Bernard , Bouchet Renaud , Guyomard Dominique 
Published: April 2011

ABSTRACTTo increase electrode cycling performance in batteries, most researchers generally focus their work on the active material optimisation. Here we show that the polymeric binder of the composite electrode may have an important role on the electrode performance. We describe a new tailored polymeric binder combination with controlled polymer-filler (carbon black) interactions that allows the preparation of new and more efficient electrode architecture. Using this polymeric binder, composite electrodes based on Li1.2V3O8 display a room-temperature cycling capacity of 280 mAh/g (C/5 rate, 3.3–2 V) instead of 150 mAh/g using a standard-type (PVdF-HFP binder) composite electrode. We have coupled SEM observations, galvanostatic cycling and electronic conductivity measurements in order to define and understand the impact of the microstructure of the composite electrode on its electrochemical performance.
All Solid-State Batteries Using Super Ionic Conductor, Thio-Lisicon – Electrode/Electrolyte interfacial Design
Authors: Kobayashi Takesh , Inada Taro , Sonoyama Noriyuki , Yamada Atsuo , Kanno Ryoji 
Published: April 2011

ABSTRACTAll solid-state ceramic lithium battery was studied using a composite anode, the thio-LISICON (Li3.25Ge0.25P0.75S4) solid electrolyte, and the Chevrel phase cathode. The nano-composite of cathode configuration reduced the interfacial resistance and provided fast-charge transfer at the interface. The self-assembled solid-electrolyte interfacial (SEI) phase was formed at the Li-Al/SE interface, while no formation was observed at the Li-In/SE interface. The SEI phase reduced the interfacial resistance and provided high charge-discharge characteristics. The all solid-state cell showed high current density of 1.3C rate and is a promising candidate for future lithium battery system.
Novel Non-aqueous Sol-Gel Synthesis of Carbon-Coated LiMPO4 (M = Fe, Mn, Co) for Lithium Ion Batteries
Authors: Yang Jingsi , Xu Jun John 
Published: April 2011

ABSTRACTA simple organic solvent based sol-gel method for synthesis of carbon-coated LiFePO4 is developed. Phase pure LiFePO4 with uniform size of 200–300 nm and no agglomeration is obtained, with 1.8 wt % surface carbon formed in-situ. Such a material gives specific discharge capacities of 150 mAh/g and 145 mAh/g at C/5 and 2C at room temperature, respectively, with desirable cycling stability. The dependence of particle size and morphology on precursor concentrations is opposite to conventional solution based methods. Other LiMPO4 (M = Mn, Co, Ni, etc) with favorable physical characteristics can be synthesized the same way.
Mesopore Size Dependence of Protonic and Lithium Ionic Conductivity of Porous Alumina
Authors: Maekawa Hideki , Shen HangYan , Fujimaki Yutaka , Kawata Kotaro , Shibata Kaoru , Kawai Masayosi , Yamamura Tsutomu 
Published: April 2011

ABSTRACTOrdered-mesoporous-Al2O3 was synthesized by the sol-gel route using neutral copolymer surfactants as templates. The pore size was controlled over the range of 3∼22 nm by using different surfactant copolymers under different synthetic conditions. Protonic conductivity of hydrated mesoporous alumina was examined for CIP treated mesoporous alumina pellet. The highest protonic conductivity was obtained as 0.004 S· cm−1 at 25 °C under 80% RH for the pellet with 15 nm averaged pores. The conductivity increased monotonically with increasing pore size under constant humidity. Quantitative determination of the concentration and the mobility of protons in hydrated mesoporous alumina was performed by 1H NMR, quasi-elastic neutron scattering (QENS) and TG/DTA measurements. Both the mobility and the concentration increased with increasing pore size. On the other hand, composites composed of synthesized mesoporous-Al2O3 and lithium iodide (LiI) was prepared. Dc electrical conductivity of 50LiI.50(mesoporous-Al2O3) was 2.6×10−4 S cm−1 at room temperature, which was considerably higher than the previously reported LiI-alumina composites. A systematic dependence of conductivity upon pore size was observed, in which the conductivity increased with decreasing the pore size except for pore size=3 nm. The 7Li diffusion constant of the composite was investigated by QENS as well as pulsed field gradient nuclear magnetic resonance (PFG-NMR). The dc conductivities showed reasonable agreement with an Einstein equation using measured diffusion constants.
Fabrication of Nanorod Arrays for Organic Solar Cell Applications
Authors: Huang Susan , Efstathiadis Harry , Haldar Pradeep , Lee Hee-Gyoun 
Published: April 2011

ABSTRACTWe report on a novel use of nanorod arrays for organic based solar cell devices. A metal foil with copper nanorods attached to the surface was developed by electrodepositing copper from a copper sulfate solution into an anodic alumina oxide (AAO) template that had been coated with a metal on one side. The AAO membrane was dissolved in NaOH leaving behind an aligned array of copper nanorods. This nanorod array was evaluated to explore the possibility of increasing the power conversion efficiency of organic solar cells. Nanorod array characteristics were investigated by focus ion beam, scanning electron microscopy, and x-ray diffraction spectroscopy. A solar cell device was made by applying a polymer layer of poly(2-methoxy-5-(3', 7'-dimethyloctyloxy)-1, 4-phenylene-vinylene) (MDMO-PPV) mixed with 6, 6 phentl-C61-butyl acid-methylester (PCBM) onto the copper nanorod array and sandwiching it with a film of poly(3, 4-ethylenedioxythiophene): poly(styrene-sulfonate) (PEDOT:PSS) applied onto a indium tin oxide coated glass substrate.
Temperature Effects on Photocurrent Generation in Polymer Hetero—Junction Photovoltaic Devices
Authors: Song Mi Yeon , Kim Kang-Jin , Kim Dong Yong 
Published: April 2011

ABSTRACTIn a heterojunction photovoltaic device of ITO/TiO2/poly(3-alkylthiophene)/Au, the photocurrent was characterized with different temperature by using regio-random (P3HT), regular (RP3HT) poly(3-hexylthiophene) and regio-regular poly(3-dodecylthiophene)(RP3DT). The regio-regularity and alky chain length affected the photovoltaic characteristics due to the difference in the hole carrier transport. The drift charge mobility of those devices were analyzed by the space charge limited current (SCLC) theory using dark current versus bias relations. The photocurrent in the devices based on poly(3-alkylthiopene)s began to decrease rapidly below a temperature at which the drift charge mobility was 10−5 cm2/V.s.
Molecular Modeling Studies on a series of Metal-Organic Frameworks
Authors: Lee Tae-Bum , Kim Daejin , Choi Seung-Hoon , Lee Eungsung , Oh Youjin , Yoon Jihye , Kim Jaheon 
Published: April 2011

ABSTRACTIn order to explore rational designs and synthetic strategies toward efficient hydrogen storage materials, quantum mechanical calculations and grand canonical Monte Carlo simulations have been carried out on a series of the Metal-Organic Frameworks containing various organic linkers. The calculations for specific surface areas and the shape of frontier orbitals for various frameworks indicate that the hydrogen storage capacity is largely dependent on the effective surface area of the material, rather than the free volume. Based on the iso-electrostatic potential surface from density functional calculations and the theoretical amount of adsorbed hydrogen from the grand canonical Monte Carlo calculations, it was also found that the electron localization around the organic linker plays an important role in the hydrogen storage capacity of Metal-Organic Frameworks. The prediction of the modeling study is supported by the hydrogen adsorption experiments with IRMOF-1 and -3, revealing the more enhanced hydrogen storage capacity of IRMOF-3 compared with that of IRMOF-1 at 77 K and H2 1 atm.
Generalized Kubas Complexes as a Novel Means for Room Temperature Molecular Hydrogen Storage
Authors: Kim Yong-Hyun , Zhao Yufeng , Heben M. J. , Zhang S. B. 
Published: April 2011

ABSTRACTWe propose that generalized Kubas complexes of molecular hydrogen with light metal elements, such as B and Be embedded in carbon nanostructures, or related Be and B materials, could offer breakthrough performance in room temperature hydrogen storage. First-principles local-density functional calculations show that hydrogen bound to these materials are intact, in similarity to physisorbed H2, but with a greatly enhanced adsorption energy in the range of 0.2–0.7 eV. The metal-H2 binding is attributed to the Coulombic interaction between holes created at the metal sites and Σ electrons of the H2. Management of the hole density and electron-hole orbital overlap thus enables us to control the binding strength of H2 for optimal storage properties.
Decomposition Behavior of Ti-doped NaAlH4 Studied using X-ray Absorption Spectroscopy at the Titanium K-edge
Authors: Bruster E. , Dobbins T. A. , Tittsworth R. , Anton D. 
Published: April 2011

ABSTRACTThe local bonding environment of Ti3+-dopant atoms in NaAlH4 after decomposition to release H2 has been studied using x-ray absorption fine structure (XAFS). The titanium K-edge spectra from doped hydride samples and the standard materials TiCl3 and TiO2 were collected in ambient atmosphere at the synchrotron source at the Center for Advanced Microstructures and Devices (CAMD). Titanium valence states present in the spectra collected from Ti-doped NaAlH4 after decomposition in air are Ti3+ and Ti4+. The Ti3+ is attributed to unreacted TiCl3. The Ti4+ present in the sample is attributed to TiO2 occurring after air oxidation. Coupled with studies of the kinetics of hydrogen desorption reactions, examination of dopant ion valence states after entry into the lattice may lead to better understanding of the interrelationship between lattice doping and desorption kinetics.