bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Crystallization Temperature Measurement Method for Combinatorial Evaluation using Infrared Thermography
Authors: Aono Yuko , Hata Seiichi , Sakurai Junpei , Shimokohbe Akira 
Published: September 2009

AbstractIn combinatorial method, combinatorial evaluation of thin film library has not been established enough, so efficiency of searching by this method is limited. One of property which has not been available combinatorial evaluation is crystallization temperature (Tx). Conventionally, Tx is measured using differential scanning calorimeter (DSC), but it is impossible to apply to the thin film library. Because its one sample size is 1×1 mm, thickness is several micrometers, and 1,089 samples (33columns and 33 rows) are integrated on one library, so the samples are too small to measure using DSC. In this study, an alternative method using infrared thermography is presented for combinatorial evaluation of Tx. This device detects infrared energy radiated from an object and its temperature can be calculated using its own emissivity.In crystallization point, electrical resistivity change is lead with structure change, and this derives emissivity change. Low electrical resistivity means less free electron that is low reflectivity and high emissivity. In heating test, while emissivity keeps constant, T-Ta curve (T: true sample temperature, Ta: apparent temperature measured by thermography) gradient is constant, but the point of Tx, T-Ta curve gradient changes by change of emissivity. Therefore transformation point can be detected by T-Ta curve gradient change. This method can be applied to thin film library, because the method requires only observation of sample surface.PtSi and PdCuSi amorphous alloys were employed to confirm this method. First, homogeneous amorphous alloy thin films were deposited on alumina wafer (20×20mm). Each of these samples was then heated in vacuum chamber with monitoring infrared images and electrical resistivity, in-situ. Obvious emissivity change could be detected at the same temperature of electrical resistivity change. This temperature also agrees enough with DSC results. In case of Pt67Si33, emissivity change was detected at 511K, and DSC result shows Tx at 516K, there is only 5K error between these values. At this temperature, both electrical resistivity and emissivity decreased and it agrees with the theory. Sample crystallization was confirmed after heating test by X-ray diffraction.Measurement on the thin film library was then considered. A quarter thin film library was used, 256 samples (16×16) are integrated and each sample size is 1×1mm separated 0.2mm grid made by sputtering on alumina wafer. For first inspection, all samples were same composition PdCuSi amorphous alloy. Every 3×3 samples, center sample were blank, i.e. alumina surface, its emissivity is stable so the surface indicated reference temperature of around samples. Alumina emissivity was calibrated using a thermo couple on the sample wafer. 184 samples in the all samples were measured at one time, Tx can be detected in all 184 samples and these value errors ranged in 15K. Therefore, this method has a great of potential in combinatorial method.
Broadband (0.3∼11THz) reflection spectroscopy using terahertz air photonics
Authors: Guo Xiaoyu , Ho I-Chen , Zhang Xi-Cheng 
Published: September 2009

AbstractPulsed THz wave spectroscopy using air as the THz wave emitter with the excitation of femtosecond laser provides intense (>100 kV/cm) and broadband THz waves (usable bandwidth from 0.3 to 11 THz). Using the air-biased-coherent-detection (ABCD) method, air can also coherently detect pulsed THz waves over a broadband spectrum. By utilizing these two technologies, we developed a prototype THz air photonics time-domain reflection spectrometer, and applied it on many materials in normal reflection geometry. Optical properties of CaCO3 crystals and several other samples in the THz range were studied. The system provided a signal-to-noise ratio (SNR) over 1000:1, with 0.1 cm−1 frequency resolution. The results acquired from both transmission and reflection measurements were then compared.
Materials Characterization using THz Ellipsometry
Authors: Hofmann Tino , Herzinger Craig M. , Woollam John A. , Schubert Mathias 
Published: September 2009

AbstractWe employ spectroscopic ellipsometry in the terahertz (0.2 to 1.5 THz) and the mid-infrared (9 to 50 THz) spectral range for the non-contact, non-destructive optical determination of the free-charge-carrier properties of low-doped Silicon bulk and thin film structures. We find that carrier concentrations as low as 1015 cm−3 in thin films can be unambiguously determined. We envision ellipsometry in the THz spectral range for future non-contact, non-destructive monitoring and control applications.
Tb-doped Aluminosilicate Oxyfluoride Scintillating Glass and Glass-ceramic
Authors: Pan Zhengda , James K. , Cui Y. , Burger A. , Cherepy Nerine , Payne S. A. , Ueda A. , Aga R. , Mu R. , Morgan S. H. 
Published: September 2009

AbstractTwo aluminosilicate oxyfluoride glass systems, a lead-cadmium-aluminosilicate oxyfluoride and a lithium-lanthanum-aluminosilicate oxyfluoride, doped with different TbF3 concentrations, have been fabricated and investigated. By appropriate heat treatment of the as-prepared glasses above, transparent glass-ceramics (TGC) were obtained. The glass-ceramics contain Tb:Pb(Cd)F2 or Tb:LaF3 nano-crystals in the glass-matrix. Differential scanning calorimetry, Raman scattering, and luminescence under both UV and β-particle excitation have been investigated on as-prepared glasses and glass-ceramics. It has been found that the terbium-doped lithium-lanthanum-aluminosilicate oxyfluoride glass exhibits good UV excited luminescence and β-induced luminescence. The luminescence yield increases for glass-ceramic compared to that of the as-prepared glass. The including of LaF3 in the glass-matrix is beneficial for a higher Tb-doping concentration and a high light yield. The light yield of lithium-lanthanum-aluminosilicate oxyfluoride glass and glass-ceramic is comparable to that of Schott IQI-301 product. However, the terbium-doped lead-cadmium-aluminosilicate oxyfluoride glass and glass-ceramic have a detrimental luminescence performance. The lead cations in the glass-matrix may create non-bridging oxygen defects, which are a strong source of charge traps, and correlated to a strong Raman “Boson” peak.
The Synthesis and Structures of Elpasolite Halide Scintillators
Authors: Yang Pin , Doty F. Patrick , Rodriguez Mark A. , Sanchez Margaret R. , Zhou Xiaowong , Shah Kanai S. 
Published: September 2009

AbstractLow-cost, high-performance gamma-ray spectrometers are urgently needed for nonproliferation and homeland security applications. Available scintillation materials fall short of the requirements for energy resolution and sensitivity at room temperature. The emerging lanthanide halide based materials, while having the desired luminosity and proportionality, have proven difficult to produce in the large sizes and low cost required due to highly anisotropic properties caused by the non-cubic crystal structure. New cubic materials, such as the recently discovered elpasolite family (A2BLnX6; Ln-lanthanide and X-halogen), hold promise for scintillator materials due to their high light output, proportionality, and toughness. The isotropic nature of the cubic elpasolites leads to minimal thermomechanical stresses during single-crystal solidification, and eliminates the problematic light scattering at the grain boundaries. Therefore, it may be possible to produce these materials in large sizes as either single crystals or transparent ceramics with high production yield and reduced costs. In this study, we investigated the “cubic” elpasolite halide synthesis and studied the structural variations of four different compounds, including Cs2NaLaBr6, Cs2LiLaBr6, Cs2NaLaI6, and Cs2LiLaI6. Attempts to produce a large-area detector by a hot forging technique were explored.
Growth of Cu-Rich/Poor CuInS2 thin films by the sequential modulated flux deposition technique
Authors: Bollero Alberto , Grossberg Maarja , Raadik Taavi , Trigo Juan Francisco , Herrero José , Gutiérrez M. Teresa 
Published: September 2009

AbstractCuInS2 has emerged during recent years as a good candidate to substitute CuInSe2 as polycrystalline absorber in thin film solar cells, mainly due to its direct band gap energy of 1.5 eV. In this study, absorber layers of both Cu-rich and Cu-poor types have been grown on soda-lime glass substrates by proper selection of the deposition parameters. The morphology and the optical properties of the resulting CuInS2 films were studied in dependence of the deposition order of the elemental constituents: alternate evaporation of the precursors, simultaneous deposition of the three constituents and sequential modulation of the evaporation fluxes.
Thermal Conductivity of Confined Ultrathin Polymers
Authors: Ghossoub Marc G , Lee Jung-Hyun , Baris Oksen T , Cahill David G , Sinha Sanjiv 
Published: September 2009

AbstractWe report ultrafast measurements of thermal transport in plasma polymerized CHF3 films deposited on standard Si substrates with Al sputtered on top. We characterize the thin films by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and spectroscopic ellipsometry and measure polymer thicknesses ranging from 33 nm down to 6 nm. Time-domain thermoreflectance (TDTR) provides quantitative data on the polymer thermal response to periodic heating from a pulsed laser source. A pump beam heats the Al layer, which acts as an opto-thermal transducer to the stack (Al-Polymer-Si) and a delayed probe beam measures the change in Al surface reflectance. We extract the polymer thermal conductivity by comparing TDTR data to a thermal diffusion model and find it to increase with decreasing polymer thicknesses below 30 nm.
Anharmonic Lifetime of Phonons in Nanophononic Semiconductors
Authors: Hepplestone Steven , Srivastava Gyaneshwar P 
Published: September 2009

AbstractWe present a theory of three-phonon interactions in nanophononic semiconductors at 300˜K. The intrinsic lifetime of phonon modes is estimated from the application of Fermi's Golden Rule, based on realistic phonon dispersion relations and a quasi-continuum model for the cubic anharmonicity. We show that the lifetime of phonon modes in the Si(0.543˜nm)/- Ge(0.543˜nm)[100] superlattice is shorter than the average of results for bulk Si and Ge. This is explained in terms of the availability of additional decay routes and an additional Dual Mass factor which arises due the different densities of Si and Ge.
Controlled Growth and Characterization of Non-tapered InN Nanowires on Si(111) Substrates by Molecular Beam Epitaxy
Authors: Chang Yi-Lu , Fatehi Arya , Li Feng , Mi Zetian 
Published: September 2009

AbstractWe have performed a detailed investigation of the molecular beam epitaxial (MBE) growth and characterization of InN nanowires spontaneously formed on Si(111) substrates under nitrogen rich conditions. Controlled epitaxial growth of InN nanowires (NWs) has been demonstrated by using an in situ deposited thin (˜ 0.5 nm) In seeding layer prior to the initiation of growth. By applying this technique, we have achieved non-tapered epitaxial InN NWs that are relatively free of dislocations and stacking faults. Such InN NW ensembles display strong photoluminescence (PL) at room temperature and considerably reduced spectral broadening, with very narrow spectral linewidths of 22 and 40 meV at 77 K and 300 K, respectively.
Low Melting Metal Catalysed Growth of Tin Disulfide Nanotubes
Authors: Yella Aswani , Mugnaioli Enrico , Panthoefer Martin , Kolb Ute , Tremel Wolfgang 
Published: September 2009

AbstractWe report here the synthesis of tin disulfide nanotubes by a vapour liquid solid growth using bismuth, a low melting metal, as a catalyst. The reaction was carried out in a single step process by heating SnS2 and bismuth in a horizontal tube furnace at 800oC. TEM analysis allowed proposing a plausible mechanism for the formation of SnS2 nanotubes. Pure material could be obtained by optimizing the reaction based on a product analysis using powder X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) combined with energy dispersive X-ray spectroscopy (EDX).
Measurements of Liquid Silicon Resistivity on Silicon Microwires
Authors: Bakan Gokhan , Cil Kadir , Cywar Adam , Silva Helena , Gokirmak Ali 
Published: September 2009

AbstractNanocrystalline silicon microwires are self-heated through microsecond voltage pulses. Nonlinear changes in current level are observed during the voltage pulse, which end with melting of the microwires. Liquid silicon resistivity is extracted as 65.9 ± 6.1 μΩ.cm from the minimum resistance of the wire during the voltage pulse. The extracted resistivity is in good agreement with previously reported values.
ZnO nanostructures epitaxially grown on ZnO seeded Si (100) substrates by chemical vapor deposition
Authors: Chen Zhuo , Salagaj Tom , Jensen Christopher , Shum Kai 
Published: September 2009

AbstractZnO nanostructures such as nanowire-networks and vertical nanorods were epitaxially grown on pre-seeded Si (100) substrates by chemical vapor deposition (CVD) method with a solid source. Crystalline ZnO seeds were prepared and controlled by the rapid thermal annealing (RTA) treatment of e-beam deposited amorphous ZnO thin films. Both epitaxially grown ZnO nanostructures and pre-deposited ZnO seeds were characterized by scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy. Excellent optical characteristics of these nanostructures such as PL line width, linearity of PL intensity as a function of excitation power density were obtained.
Guided growth of in-plane lateral SiNWs led by indium catalysts
Authors: Yu Linwei , Moustapha Oumkelthoum , Oudwan Maher , Roca i Cabarrocas Pere 
Published: September 2009

AbstractHere we report a new in-plane solid-liquid-solid (IPSLS) mode for obtaining in-plane silicon nanowires (SiNW), which can be controlled and directly guided into various desired patterns for circuit architecture. Indium catalyst drops are firstly formed by a H2 plasma reduction of a thin layer of ITO on Corning glass substrate and then covered by an a-Si:H layer deposited at low temperature (100oC-200oC). The growth of SiNWs is activated in a reacting-gas-free thermal annealing process and led by the indium catalyst drops, that absorb and transform the a-Si:H matrix into crystalline SiNWs behind. At least two guided modes, that is, the a-Si:H channel guided mode and the step edge guided mode, can be applied to effectively control the growth routes for the lateral SiNWs. This guided growth of the IPSLS SiNWs lays an important basis for realizing various SiNWs-based device applications directly on top of low-cost substrates.
Non-Resonant Two-Photon Absorption-Induced Photoluminescence Study on ZnO Nanostructures Epitaxially Grown on Si (100) Substrates by Chemical Vapor Deposition Method
Authors: Chen Zhuo , Salagaj Tom , Jensen Christopher , Strobl Karlheinz , Hongpinyo V , Ooi Boon , Nakarmi Mim , Shum Kai 
Published: September 2009

AbstractWe report on experimental results of non-resonant two-photon absorption-induced photoluminescence in ZnO nanostructures, which may act as a possible route to excite ZnO nanostructure based lasers. Epitaxial ZnO nanorod-like nanostructure was grown on pre-seeded Si (100) substrates by chemical vapor deposition (CVD) method with a mixed ZnO/C solid source. Crystalline ZnO seeds were prepared and controlled by the rapid thermal annealing (RTA) treatment of e-beam deposited amorphous ZnO thin films with various thicknesses.
CdSe Sensitized ZnO nanowire/polymer based p-i-n Heterojunction Solar Cell
Authors: Nadarajah Athavan , Word Robert C , Koenenkamp Rolf 
Published: September 2009

AbstractWe report a novel hybrid p-i-n heterojunction solar cell consisting of an undoped CdSe quantum dot film sandwiched between electrodeposited n-type ZnO nanowires on a compact ZnO thin film/FTO and a spin-coated hole-conducting layer. Microscopic studies show the conversion of CdSe quantum dots into conformal and continuous polycrystalline thin film coatings on ZnO nanowires upon annealing in CdCl2/ambient air. The morphology change of the CdSe quantum dot layers then provided excellent charge transfer between the absorber layer and the contiguous layers. The quantum-dot-sensitized ZnO nanostructured solar cells exhibited short-circuit current densities ranging from 5 to 10 mA/cm2 and open-circuit voltages of 0.4–0.6 V when illuminated with an 85 mW/cm2 quartz-halogen spectrum. External quantum efficiencies as high as 55–60% were also achieved.
Viscoelastic Inks for Direct-Write Microfabrication of Single-Chamber Micro Solid Oxide Fuel Cells with Coplanar Thick Electrodes
Authors: Kuhn Melanie , Rao Ranjeet B. , Therriault Daniel 
Published: September 2009

AbstractSingle-chamber micro solid oxide fuel cells (SC-μSOFCs) with coplanar electrodes were fabricated using a robotically controlled direct-write microfabrication approach. Viscoelastic, gel-based inks were employed to create homogeneous electrodes of controlled width and interelectrode distance as well as uniform cross-sectional thickness. Electrode powders, NiO-YSZ (yttria-stabilized zirconia) for the anode and (La0.8Sr0.2)0.98MnO3-YSZ for the cathode, were first dispersed with a cationic polyethyleneimine solution. Polyacrylic acid was added to induce a fluid-to-gel transition. The rheology of the fabricated inks was characterized. The inks were then extruded through cylindrical micronozzles and deposited onto YSZ electrolyte substrates using a robotic deposition apparatus. Thickness and width of the sintered electrodes were close to the diameter of the extrusion nozzle. The improved shape retention of the deposited electrodes also enabled the fabrication of continuous electrodes with square cross-section. The cathode adhered very well to the electrolyte during sintering. However, the mismatch between the thermal expansion coefficient of anode and electrolyte seems to cause detaching and breaking of the anode so that electrochemical characterization of the fabricated cells was not yet possible.
Magneto-transport and Magnetic Properties of Fe Doped Nanometric Polycrystalline La0.7Sr0.3MnO3 CMR Manganites
Authors: Paul Sanjoy , Nath Tapan K. 
Published: September 2009

AbstractWe have investigated the effect of 3d-transition metal Fe (Iron) doping at Mn site of nanometric polycrystalline La0.7Sr0.3MnO3 (i.e. La0.7Sr0.3Mn1-xFexO3; 0 ≤ x ≤ 0.1) CMR manganites on magneto-transport and magnetic properties. Nanocrystalline Fe doped La0.7Sr0.3MnO3 powders were synthesized through chemical route “Pyrophoric Reaction Process” and calcinated at 850°C for 5 hrs. X-ray diffraction (XRD) patterns of synthesized powder indicate that all samples are having perovskite structure without any secondary impurity phase. Average crystallite size was found to be 20 nm using Debye Scherer formula. Transmission electron micrographs (TEM) show that the average particle sizes are in nanometric regime (φ ˜ 50 nm) and samples are polycrystalline in nature which was observed through selected area electron diffraction (SEAD) patterns. The effect of Fe doping at Mn site of La0.7Sr0.3MnO3 was found to change substantially the magnetic and transport properties without modifying lattice structure. The suppression of magnetic and transport properties were observed due to dilution of double exchange mechanism in Mn3+- O2--Mn4+ network in La0.7Sr0.3MnO3.
Histological and Mechanical Evaluation of the in vivo Bone-bonding Ability on the K2TinO2n+1/β-Ti Alloy as a Novel Bioactive Material
Authors: Cui Chunxiang , Qi Y. M. , Zhang M. F. , Li J. G. , Liu S. J. , Xue X. L. , Huang N. 
Published: September 2009

AbstractThe purpose of this study was to histologically and mechanically appraise the in vivo bone-bonding abilities of K2TinO2n+1 coated and uncoated Ti-15Mo-3Nb (TMN) implants. According to GB/T16886.6－1997 biological evaluation of medical devices Part 6:Tests for local effects after implantation, the two types of implants were implanted into the proximal metaphyses of Chinese white rabbits’ femurs for 12, 26 and 52 weeks and investigated by pushing out test, scanning electron microscopy (SEM) attached to an energy-dispersive X-ray micro-analyzer (EDX) and light microscopy. The bone-bonding abilities of the K2TinO2n+1 biocoating /Ti-15Mo-3Nb (KBT) gradient biomaterial implants were higher than those of T implants at different periods of implantation. The K2TinO2n+1 biocoating (KB) could stimulate new bone rapid formation at the early stages of implantation. And the implants with the biocoating eventually bonded to bone directly, with no intervening soft tissue layer, that was an osseocoalescence. However, the type of bone-bonding between TMN titanium alloy implants and bone was a simple osseocoaptation. The more excellent bone-bonding ability of the KBT implants should be attributed to the superficial characteristics, the bioactivity of low potassium titanate and biostability of high potassium titanate.
Hot Embossing Of Microchannels in Cyclic Olefin Copolymers
Authors: Leech Patrick William 
Published: September 2009

AbstractThe hot embossing properties of Cyclic Olefin Copolymer (COC) have been examined as a function of comonomer content. Six standard grades of COC with varying norbornene content (61-82 wt%) were used in these experiments in order to provide a range of glass transition temperatures, Tg. All grades of COC exhibited sharp increases in embossed depth over a critical range of temperature. The transition temperature in embossed depth increased linearly with norbornene content for both 35 and 70 μm deep structures. At temperatures above this transition, the dimensions of the embossed patterns were essentially independent of COC grade, the applied pressure and duration of loading. Channels formed above the transition in a regime of viscous liquid flow were extremely smooth in morphology for all grades. The average surface roughness, Ra, measured at the base of the channels decreased sharply at the transition temperature, with a levelling off at higher temperatures. Grades of COC with higher norbornene content exhibited extensive micro-cracking during embossing at temperatures close to the transition temperature.
Phosphate-dependent DNA Immobilization on Hafnium Oxide for Bio-Sensing Applications
Authors: Fahrenkopf Nicholas M , Oktyabrsky Serge , Eisenbraun Eric , Bergkvist Magnus , Shi Hua , Cady Nathaniel C 
Published: September 2009

AbstractHafnium(IV) oxide (HfO2) has replaced silicon oxide as a gate dielectric material in leading edge CMOS technology, providing significant improvement in gate performance for field effect transistors (FETs). We are currently exploring this high-k dielectric for its use in nucleic acid-based FET biosensors. Due to its intrinsic negative charge, label-free detection of DNA can be achieved in the gate region of high-sensitivity FET devices. Previous work has shown that phosphates and phosphonates coordinate specifically onto metal oxide substrates including aluminum and titanium oxides. This property can therefore be exploited for direct immobilization of biomolecules such as nucleic acids. Our work demonstrates that 5’ phosphate-terminated single stranded DNA (ssDNA) can be directly immobilized onto HfO2 surfaces, without the need for additional chemical modification or crosslinking. Non-phosphorylated ssDNA does not form stable surface interactions with HfO2, indicating that immobilization is dependent upon the 5’ terminal phosphate. Further work has shown that surface immobilized ssDNA can be hybridized to complementary target DNA and that sequence-based hybridization specificity is preserved. These results suggest that the direct DNA-HfO2 immobilization strategy can enable nucleic acid-based biosensing assays on HfO2 terminated surfaces. This work will further enable high sensitivity electrical detection of biological targets utilizing transistor-based technologies.