bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arsenic Trapping and its Effect on Enhanced Diffusion
Authors: Brindos Richard , Law Mark E. , Jones Kevin S. , Andideh Ebrahim 
Published: April 2011

ABSTRACTCVD grown boron marker layers were used to monitor the release of silicon interstitials from an arsenic doped surface region that was subsequently implanted with silicon. These structures were annealed for various times at 750°C in a nitrogen ambient. A comparison of boron spike enhancement and defect dissolution is made. It is shown that enhancement values from the Si+ implant were reduced at short times for samples containing arsenic compared to samples implanted with Si+ alone or As− alone. The TEM results showed that defect densities were dramatically reduced for the samples containing As. These results imply that the previously reported reduction in {311} formation observed in As doped wells is most likely not a Fermi level effect and is consistent with the formation of As interstitial clusters (AsIC's). The data shows that AsIC's form and control extended defect formation and slow the enhanced diffusion.
Micromechanical Thin-Film Characterization
Authors: Scherge M. , Mollenhauer O. , Spiller F. , Schaefer J. A. 
Published: April 2011

ABSTRACTMicroelectromechanical systems (MEMS) can be regarded as advanced film-based devices. Although the dimensions of a MEMS are in the range of micrometers to millimeters, due to low mass and contact area the interaction of the micro parts is confined to the upper monolayers of the material. To achieve a good performance as well as a long lifetime it is necessary to control the adsorbate coverage of the micro parts. Besides the tools of surface science (XPS, HREELS, AES, … ) a precise characterization of the adsorbate film with respect to mechanical properties (adhesion, friction, mechanically induced desorption) is required. Those needs are met with a new generation of test equipment comprising of sensors and actuators, thus, rendering the instruments also a MEMS. Force sensing devices made of glass are introduced to measure ultra low deflections caused by the interaction of the micro parts via the adsorbate layer. The devices combine precisely etched glass structures (bending beams,) with fiber optics.
Statistical Aspects of Martensitic Nucleation
Authors: Olson G. B. , Tsuzaki K. , Cohen Morris 
Published: April 2011

AbstractAnalysis of the Cech-Turnbull small-particle martensitic transformation experiments in terms of heterogeneous nucleation theory defines an exponential nucleation-site potency distribution. Sensitive acoustic-emission detection of martensitic nucleation events shows that the same form of distribution describes the behavior of bulk polycrystals, and the influence of heat treatment on the distribution amplitude can be identified in this way. On the assumption of a random distribution of pre-existing nucleation-site orientations, the effect of applied stress on the effective potency distribution has been calculated, thus accounting for an observed nonlinear stress dependence of the transformation kinetics. The model also predicts a transformation “yield locus” for multiaxial stress.
Anomalous Behavior of Peak Resistance Temperature for low x in As-Deposited La1-xCaxMnO3 Films on NdGao3 and SrTiO3 Substrates
Authors: Broussard P. R. , Cestone V. C. 
Published: April 2011

AbstractWe have grown thin films of La1-xCaxMnO3 using off-axis cosputtering for x ≤ 1/3 onto (001) NdGaO3 and (100) SrTiO3 substrates from individual targets of LaMnO3 and La2/3Ca1/3MnO3. As-deposited films of La2/3Ca1/3MnO3 on NdGaO3 have a peak resistance temperature of ≈ 260 K. We see a difference in the peak temperature between the two types of substrates of ≈ 15 K, with samples on NdGaO3 having higher peak temperatures. As the value of x is reduced from 1/3, the peak resistance temperature decreases until x ≈ 0.15, when the peak temperature has an upturn. Even down to x=0 we still observe a metal-insulator transition (at 185 K) for films on NdGaO3, while samples on SrTiO3 show only activated behavior. We also find a scaling relationship between the peak temperature and the resistivity activation energy of the films.
Silicon-Oxynitride (SiON) for Photonic Integrated Circuits
Authors: Salemink H. W. M. , Horst F. , Germann R. , Offrein B. J. , Bona G. L. 
Published: April 2011

AbstractWe report on the fabrication and analysis of silicon-oxynitride (SiON) as core material for silicon-based planar photonic waveguide circuits. Features of devices made of this particular SiON material are: (1) a silicon-compatible technology (low-cost perspective), (2) a waveguide structure with high dielectric index contrast, allowing a very compact device layout (approximately 10× smaller radius of curvature than conventional doped SiO2 technology), (3) a low optical loss < 0.15 dB/cm, in the 1550 nm telecommunication window and (4) a negligible polarization dependence. The materials aspects and resulting analyses of the SiON layers as well as particular device properties are described.
Barium Titanate Ceramic/Ceramic 0–3 Composites for Ultrasonic Transducer Applications
Authors: Cheung M. C. , Chan H. L. W. , Zhou Q. F. , Choy C. L. 
Published: April 2011

AbstractBarium titanate (BaTiO3) 0–3 ceramic/ceramic composite thick films (∼16μm) for ultrasonic transducer applications were fabricated by a modified sol-gel process. Nano-sized BaTiO3 powder was dispersed in a sol-gel matrix of BaTiO3 to form a 0–3 composite solution. Films were prepared by spin coating and then annealed at various temperatures. The crystallization of the composite film was studied by X-ray diffraction. The dielectric permittivity and the ferroelectric properties of the film were also measured.
Time-Dependent Exciton Correlations in Nanoscale Quantum Dot
Authors: Jönsson Lars , Sakhel Roger , Wilkins John W. 
Published: April 2011

ABSTRACTIn nanoscale quantum dots, subpicosecond laser pulses can induce and probe strong time-dependent Coulomb correlations between confined electrons and holes. Correlation dynamics for one or two electron-hole pairs driven by both interband and intraband lasers can be simulated by numerical solution of the time-dependent Schrddinger equation within a configuration-interaction description. For example, Coulomb correlations of two electrons and two light holes in a 5×25×25 nm3 GaAs quantum dot yield strong oscillations in the luminescence. Pure correlation effects are revealed by a carefully chosen sequence of three circularly polarized subpicosecond laser pulses. For this case, the Coulomb and electron-laser matrix elements were calculated within the effective-mass approximation with infinite potential walls. For a quantum dot with an internal tunneling barrier that splits the energy levels on the 10 meV scale, correlation effects couple the interband and intraband optical response. Work in progress aims at more realistic geometries, finite outer potential walls, and better description of the band structure, using real-space methods, multi-band models, and tight-binding Hamiltonians. With the help of 'dynamic state selection,' simulation times can be reduced by a factor of 5–10. Dynamic state selection allows the computer, by generic selection criteria, to use only those determinants that are momentarily most important. This approach is especially useful in multi-pulse simulations where the coupled determinants belong to different classes at different times.
An Ivestigation of Temperature-Manipulated Size and Shape Evolution of Preformed Core-Shell Nanoparticles
Authors: Maye M.M. , Zheng W.X. , Leibowitz F.L. , Ly N.K. , Eichelberger H.H. , Zhong C.J. 
Published: April 2011

AbstractThis paper presents a study of heating-induced size and shape change for pre-synthesized composite nanoparticles of ∼2 nm gold cores encapsulated with alkanethiolate monolayers. The results have demonstrated an evolution in size and shape of the nanoparticles towards monodispersed larger core sizes with well-defined and highly-faceted morphologies. The evolved particles were encapsulated with the thiolate shells. The morphological and structural evolutions were characterized using TEM, XRD, UV-Vis and FTIR spectroscopy. While temperature-driven crystal growth is known for non-encapsulated particles, the evolution of the thiolate-encapsulated nanoparticles in solutions into well-defined morphologies represents an intriguing example of temperature manipulations of nanoparticle monodispersity and shape.
Coarse Grained Free Energy Functional for Lennard-Jones Systems
Authors: Gracheva M. E. , Rickman J. M. , Gunton J. D. , Coffey D. C. 
Published: April 2011

AbstractResults are presented for the coarse grained distribution function and Ginzburg-Landau free energy function for coexistence of liquid and gas phases. These distribution functions were obtained by two different methods: 1) the compilation of particle density information from different coarse-grained cells using the canonical ensemble, and 2) the compilation of energy and density information from a single simulation cell by tuning the chemical potential using the grand-canonical ensemble. Both methods permit the calculation of a coarse-grained free energy functional which links the atomic and mesoscopic length scales.
Use of the Vacuum Arc Discharge for the Surface Modification
Authors: Kovalenko Vladimir A. 
Published: April 2011

AbstractSteel surface saturation by nitrogen (nitriding) results in a high increase in surface hardness and a decrease in friction rate. This treatment is widely used to increase the lifetime of cutting tools and wearing parts in machines.A new approach of steel surface treatment by using the vacuum arc discharge in nitrogen is presented. The apparatus uses two arc vacuum discharges. The first discharge is a metal vapor discharge and serves for both the cleaning- heating of the treated surface and for the initiation of the second vacuum arc discharge in nitrogen. The vacuum arc source of metallic plasma allows us the simultaneous implantation of desirable metals and surface saturation by nitrogen. The developed arc vacuum discharge method shortens the nitriding time 2 to 3 times in comparison to the glow discharge technology. The suggested method of the surface treatment is suitable for a wide variety of steels. The hardness measurement results of nitriding and combined chromium with nitriding treatments of several steel samples are presented and discussed.
ECR Plasma Oxidation: Dependence on Energy of Argon Ion
Authors: Matsuo S. , Yamamoto M. , Sadoh T. , Tsurushima T. , Gao D. W. , Furukawa K. , Nakashima H. 
Published: April 2011

AbstractEffects of ion-irradiation on oxidation of silicon at low temperatures (130°C) in an argon and oxygen mixed plasma excited by electron cyclotron resonance (ECR) interaction are investigated. First, dependence of energy and flux of incident ions on the flow rate and the microwave power is evaluated. It is shown that the flow rate and the microwave power are key parameters for controlling the energy and the flux of incident ions, respectively. Second, growth kinetics of the oxide films are studied. The growth rate depends on the energy and the flux of argon ions irradiated to the substrate, and the growth thickness increases proportionally to the root square of the oxidation time. Thus, the growth rate is limited by diffusion of oxidants enhanced by irradiation with argon ions. The effect of substrate bias on oxidation characteristics is also discussed. The electrical properties of the oxide films are improved by increasing the bias. The improvement is due to the reduction of damage at the surface of the substrate induced by the irradiation.
Layer Splitting by H-Ion Implantation in Silicon: Lower Limit on Layer Thickness?
Authors: Qian C. , Terreault B. 
Published: April 2011

AbstractThe Smart-Cut™ process and its variants involve H and/or He ion implantation and annealing to neatly exfoliate a layer of material as thin as the ion range. At low ion energy, as required for further miniaturisation, several effects may inhibit the process. We implanted undoped Si (100), (110) and (111) with 5 keV H or D ions at doses below (3–4×1016/cm2) or above (5.5×1016/cm2) the critical dose for blistering. The samples were either isochronally annealed for 1h or 2h in three steps at 500, 550 and 600°C, or subjected to thermal desorption spectroscopy (TDS) with linear ramps of 7.5 K/min up to 500, 550 or 600°C. The surface morphology was observed at each step by scanning electron or atomic force microscopy. Below the critical blistering dose, TDS only shows a broad high temperature (∼525°C) peak, while above that dose, a low temperature peak (∼360°C) also appears, though weakly in the case of (110) samples. The exfoliated area (as % of total surface) increases with temperature, and also varies with wafer orientation, being minimum for (110) samples and maximum for (111) samples. This orientation effect is much more pronounced for H-implants than for D-implants. All these trends indicate that ion channelling leads to an inhibition of exfoliation.
Growth of Metal Nucleus on Polyimide Surface with Photochemical Reaction
Authors: Tomita M. , Murahara M. 
Published: April 2011

AbstractCircuit patterned nucleation of copper or nickel atoms onto polyimide surface was demonstrated by using ArF excimer laser (λ=193nm) and copper sulfate aqueous solution (CuSO4.5H2O+nH2O), or nickel sulfate aqueous solution (NiSO4–6H2O+nH2O) in an atmospheric pressure. Photo-excited C-H bonds of the polyimide surface were effectively dehydrated with hydrogen atoms which were photodissociated from the water. The dangling bonds of the dehydrated hydrogen atoms were combined with the oxygen and the copper or nickel atoms that were photodissociated by CuSO4 solution or NiSO4 solution. Thus, C-O-Cu bonds or C-O-Ni bonds were formed on the surface. After this copper and nickel substitution, it was carried out onto the nucleated parts by usual electroless plating at 70 °C. In this process, the conductive circuit patterned copper or nickel thin film was deposited on polyimide surface.
Etching and Surface Smoothing with Gas-Cluster Ion Beams
Authors: Fenner D. B. , Torti R. P. , Allen L. P. , Toyoda N. , Kirkpatrick A. R. , Greer J. A. , Difilippo V. , Hautala J. 
Published: April 2011

AbstractSurface processing of microelectronic materials by bombardment with nanoparticles of condensed gases (i.e., clusters) in the form of an ion beam, makes possible etching and smoothing of those surfaces to very high figures of merit. As this is not possible with any conventional ion method, gas-cluster ion-beam systems have great potential in manufacturing. The formation of gas clusters and their collision with surfaces provides an interesting arena for novel physics and surface science. This paper outlines a physical model for the clusters and surface interactions, and provides examples of surface processing. In particular, the reduction of surface roughness while etching by cluster-ion bombardment is illustrated for various materials utilized in microelectronics.
Fabrication of High-Quality Ion-Beam Deposited Cubic Oxide Template Films on Meter-Length Substrates
Authors: Arendt P. N. , Groves J. R. , Foltyn S. R. , Jia Q. X. , Peterson E. J. , Depaula R. F. , Dowden P. C. , Coulter J. Y. , Ma M. 
Published: April 2011

AbstractIon-beam assisted deposition was used to fabricate biaxially aligned cubic zirconia on flexible metal substrates. These films were used as templates for heteroepitaxially deposited YBa2Cu3O7-δ (YBCO) films. The quality of the crystalline texture of the template films has a direct influence on the superconducting properties of the final YBCO films. We describe our efforts to fabricate high-quality cubic zirconia templates on short-length substrates processed in stationary mode and meter-long substrates processed in continuous mode. Our best phi scan FWHM values for the films on the meter-long tapes were 12.6 degrees for the template and 6.1 degrees for the overcoated YBCO. This meter-long tape had a self-field, 75 K, superconducting critical current of 122 amps.
Analytical High-Resolution TEM Study on Au/TiO2 Catalysts
Authors: Akita T. , Tanaka K. , Tsubota S. , Haruta M. 
Published: April 2011

AbstractHRTEM(High-Resolution Transmission Electron Microscope), HAADF-STEM (High Angle Annular Dark Field Scanning Transmission Electron Microscope) and EELS(Electron Energy Loss Spectroscopy) techniques were applied for the characterization of Au/TiO2 catalysts. HAADFSTEM provides precise size distributions for Au particles smaller than ∼2nm in diameter. It was observed that many small particles under 2nm were supported on anatase TiO2 having a large surface area. The HAADF-STEM method was examined as a way to measure the shape of Au particles. EELS measurements were also used to examine the interface between Au and TiO2 support to study electronic structure effects.
LEEM Investigations of bcc Metals Grown Heteroepitaxially on Sapphire
Authors: Swiech W. , Ondrejcek M. , Appleton R.S. , Durfee C.S. , Mundschau M. , Flynn C.P. 
Published: April 2011

AbstractWe describe studies of refractory metals Mo and Nb, grown heteroepitaxially in the (011) orientation on sapphire (1120), using low energy electron microscopy (LEEM). A wide variety of structural and dynamical phenomena are observed and recorded as video sequences. These are organized here in five categories as follows. First are surface impurity phases identified by LEED. It is an important point, established here for Mo, that almost ideally clean surfaces with mainly single stepped terraces, can be prepared on thin films for use in surface science. Second, surface reconstruction phenomena can also be identified by diffraction. This is illustrated here by a reconstruction of the Nb surface, with two equivalent domains that form a stripe phase, owing to competing long and short range interactions. Detailed studies of nucleation, fluctuations and the equilibrium of these variants are described. The third area is surface topography, illustrated here by almost ideal stepped surfaces of Mo and Nb at high temperatures, and by nanofaceting by step edge coalescence to form {110} facets on Nb at lower temperatures. The phase diagram for nanofaceting is discussed. Fourth are processes at the internal Al2O3-metal interface, as interfacial dislocations, misorientation steps and defects become visible in the LEEM image through the displacement fields they cause. The final category includes bulk process where the observed dynamics of threading screw and edge dislocations and accompanying slip traces reveal their release at high temperatures from Cottrell atmospheres. The kinetics are tracked as surface diffusion smooths dislocation slip traces, and the interactions among dislocations and surface steps are measured.
SEM/EDX Spectrum Imaging and Statistical Analysis of a Metal/Ceramic Braze
Authors: Kotula Paul G. , Keenan Michael R. , Anderson Ian M. 
Published: April 2011

AbstractEnergy dispersive x-ray (EDX) spectrum imaging has been performed in a scanning electron microscope (SEM) on a metal/ceramic braze to characterize the elemental distribution near the interface. Statistical methods were utilized to extract the relevant information (i.e., chemical phases and their distributions) from the spectrum image data set in a robust and unbiased way. The raw spectrum image was over 15 Mbytes (7500 spectra) while the statistical analysis resulted in five spectra and five images which describe the phases resolved above the noise level and their distribution in the microstructure
The Vibrational Density-of-States of Nanobundles of Single Wall Carbon Nanotubes: An Inelastic Neutron Scattering Study
Authors: Rols S. , Benes Z. , Sauvajol J.L. , Papanek P. , Anglaret E. , Coddens G. , Dianoux A.J. , Fischer J.E. 
Published: April 2011

ABSTRACTThe phonon density of states of single-wall carbon nanotubes (SWNT) was measured by inelastic neutron scattering (INS) in a large energy range (0 to 120 meV). New information on the vibrational dynamics of SWNT is reported and compared with calculated density-of-sates. At lower frequencies (< 12 meV) we observe a peculiar energy dependence which we attribute to contributions from inter-tube modes in the 2D lattice of SWNT bundles, and also from effects of intertube coupling on the intra-tube excitations.
Purification and Characterization of Single-Walled Carbon Nanotubes
Authors: Kim H.Y. , Choi W.B. , Lee N.S. , Chung D.S. , Kang J.H. , Han I.T. , Kim J.M. , Moon M.H. , Kim J.S. 
Published: April 2011

ABSTRACTSingle-walled carbon nanotubes (SWNTs) were purified and cut into short length by the liquid phase oxidation using the typical oxidants such as HNO3, H2SO4 and their mixture. The SWNTacid solutions were refluxed at high temperature, filtered on poly tetra-fluoro ethylene (PTFE) filter paper. rinsed with distilled water, and then dried at room temperature. In order to find optimum purifying condition, acid solutions were made by mixing nitric / sulfuric acid by the different volume ratio. The reaction time was also varied from 1h to 6h. Through this method, purified SWNTs with the length of less than 2μm were successfully obtained, which was confirmed by scanning electron microscopy (SEM). From transmission electron microscopy (TEM) analysis, it was verified that SWNTs were purified with little damage on surface and metal catalysts were efficiently removed when sulfuric acid was mixed, which was also confirmed by energy disperse spectrum analysis (EDS). Moreover, size distribution of the purified SWNTs was characterized with Field Flow-Fractionation (FFF) method.
Density and sp3 Content in Diamond-Like Carbon Films by X-ray Reflectivity and Electron Energy Loss Spectroscopy
Authors: Libassi A. , Ferrari A. C. , Stolojan V. , Tanner B. K. , Robertson J. , Brown L. M. 
Published: April 2011

ABSTRACTGrazing angle x-ray reflectivity (XRR) is used to study density, thickness, internal layering and roughness of a variety of carbon samples, with and without hydrogen and nitrogen. The bulk mass density of optimised tetrahedral amorphous carbon (ta-C) is 3.26 g/cm2, for which Electron Energy Loss Spectroscopy (EELS) found a sp3 fraction of 85%. Combining XRR and EELS we benchmark the dependence of sp3 fraction on density for hydrogen-free carbons. Hydrogenated ta-C (ta-C:H) deposited by electron cyclotron wave resonance (ECWR) reactor from acetylene gas, has a density of 2.35 g/cm3, 75% sp3 and ∼30% hydrogen. These data provide a similar validation for density and sp3 EELS data for hydrogenated DLCs. XRR can also reveal internal layering in films, and indeed less dense layers may be found at the surface or interface of ta-C films, but no such layers are found in ta-C:H films.
Micro-Wear Scan Test on the Carbon Overcoats as Thin as 6 nm or Less
Authors: Wu T.W. , Scharf Thomas W. , Zhang Hong , Barnard John A. 
Published: April 2011

ABSTRACTNitrogen-doped carbon (CNx) overcoats, ranging from I to 6nm in thickness, were deposited on magnetic recording disks by a DC-sputtering process. A critical load, based on the first occurrence of coating damage, was used as a semi-quantitative measure of the mechanical strength of these overcoats. It was found that the critical load decreased in a nearly linear manner with the CNx thickness from 6nm down to ∼2nm regime. However, the lnm thick CNx coating deviated from this trend with a significant decrease in critical load. High-resolution SEM was employed to find the critical loads as well as to reveal the details of the coating wear morphology and the CNx failure mechanism