bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of Colloidal Crystal Growth by External Fields
Authors: von Rhein Elisabeth , Bielawny Andreas , Greulich-Weber Siegmund 
Published: April 2011

AbstractSynthetic opals serve as templates for the most promising three-dimensional photonic crystals, so-called inverted opals. The time consuming growth of artificial opals by self-assembly of monodisperse sub-micron spheres made of silica or organic materials resulting in fcc and hcp colloidal crystals usually yields in limited crystal qualities. The large scale fabrication and thus their application in photonics suffer from the reproducible growth of defect-free extended bulk crystals. In this paper we propose a sonic wave supported fast colloidal crystal growth in a centrifugal field. White noise acoustic irradiation is thought to realize an artificial temperature allowing particle diffusion during crystal growth.
Growth of Epitaxial Inas Nanowires in a Simple Closed System
Authors: Park Hyun D , Prokes Sharka M , Cammarata Robert C 
Published: April 2011

AbstractThe epitaxial growth of InAs nanowires on an InAs (111) substrate in a sealed quartz tube is described. The method is quite simple and fast, and uses only a bare InAs substrate and a gold colloid coated InAs (111) substrate. High quality InAs nanowires can be produced by this technique.
Amorphization and thermal stability of mechanically alloyed Zr54Cu19Ni8Al8Si5Ti5O1
Authors: Kapaklis Vassilios , Georgiopoulos Athanasios , Schweiss Peter , Politis Constantin 
Published: April 2011

AbstractIn the present work we have intentionally introduced significant amount of oxygen to Zr- based alloys. Samples were prepared either by high energy ball milling of the elemental powders and single phase α-ZrO0.43 at the appropriate stoichiometry, or by melting in an Zr-gettered arc melting facility, in both cases under purified argon atmosphere. The effect of small amounts of oxygen (∼1 at. %) on the amorphization process and the thermal stability of mechanically alloyed Zr54Cu19Ni8Al8Si5Ti5O1 powders and arc melted bulk samples was studied by X-ray diffraction and differential scanning calorimetry. It was found that the introduction of oxygen to the alloy composition does not inhibit the amorphization but enhances greatly the thermal stability of the mechanically alloyed amorphous powders. Compared to samples without oxygen prepared either by arc melting or mechanical alloying, samples with oxygen show an increase of the supercooled liquid region from ΔTx−g=Tx−Tg=117 °C to 141 °C where Tx is the crystallization and Tg the glass transition temperature. The glass transition for the mechanically alloyed samples (Tgma) remains unaffected at 336 °C.
Grain Boundary Structure Evolution in Nanocrystalline Al by Nanoindentation Simulations
Authors: Dupont Virginie , Sansoz Frederic 
Published: April 2011

AbstractThe nanoindentation of a columnar grain boundary (GB) network in nanocrystalline Al has been examined by atomistic simulation. The goal of this study was to gain fundamental understanding on the relationship between structure evolution at GBs and incipient plasticity for indenter tips significantly larger than the average grain size. The nanoindentation simulations were performed by quasicontinuum method at zero temperature. A GB network made of vicinal and high-angle <110> tilt GBs was produced by generating randomly-oriented 5-nm grains at the surface of a 200 nm-thick film of Al. The major findings of this investigation are that (1) nanocrystalline GB networks profoundly impact on the nanoindentation response and cause significant softening effects at the tip/surface interface; (2) GB movement and deformation twins are found to be the predominant deformation modes in columnar Al, in association with shear band formation by GB sliding and intragranular slip, and crystal growth by grain rotation and coalescence; and (3) the cooperative processes during plastic deformation are dictated by the atomic-level redistribution of principal shear stresses in the material.
Atomic-scale simulations of strain localization in a single-component three-dimensional model amorphous solid
Authors: Shi Yunfeng , Falk Michael L 
Published: April 2011

AbstractMolecular dynamics is used to simulate model non-crystalline solids described by a single-component Dzugutov system. The solids are produced by quenching equilibrium liquids at different cooling rates. These are then tested in uniaxial compression. Samples produced at high cooling rates exhibit homogenous deformation while samples quenched at low cooling rates exhibit localized deformation. Shear bands are shown to correspond to regions of depleted short-range order as determined by a Frank-Kasper criterion.
New transparent conductors anatase Ti1−xMxO2 (M=Nb,Ta): transport and optical properties
Authors: Furubayashi Yutaka , Hitosugi Taro , Yamamoto Yukio , Hirose Yasushi , Otani Makoto , Nakajima Kiyomi , Chikyow Toyohiro , Shimada Toshihiro , Hasegawa Tetsuya 
Published: April 2011

AbstractWe have discovered new transparent conducting oxides (TCOs), anatase Ti1-xMxO2 (M=Nb,Ta), in thin film form. Both films with 0.03 ≤ × ≤ 0.06 showed resistivity of 2−3 × 10−4 Ωcm and internal transmittance of ∼95% in the visible light region (40 nm in thickness), at room temperature. These values are comparable to those of typical TCOs, such as In2−xSnxO3 (ITO).
Photoinduced Solid Phase Transformation in Vanadium Dioxide Films
Authors: Lysenko Sergiy , Vikhnin Valentin , Rua Armando , Fernandez Felix , Liu Huimin 
Published: April 2011

AbstractLaser induced insulator-to-metal phase transition in VO2 thin films was explored using femtosecond optical pump-probe spectroscopy. The transient reflection and relaxation processes in VO2 were observed during phase transition on 10-11 - 10-9 temporal-scale. Optical generation of carriers in VO2 initiates extremely fast changes in reflectivity which is strongly dependent on pump fluence. Analysis of transient optical properties allows suggesting the excitonic-controlled mechanism responsible for the light-induced phase transition in VO2.
High density BaCeO3 ceramics sintered using microwave irradiation
Authors: Vanetsev Alexander Sergeevitch , Orlov Andrei Vladimirovitch , Tretyakov Yurii Dmitrievitch 
Published: April 2011

AbstractThe goal of this work was to investigate the capabilities of high-power microwaves in manufacture of small-grained barium cerate ceramics. Having compared the samples sintered in the microwave and the thermal fields, we inferred that the microwave sintering occurs at far higher rates. It is also noteworthy that microwave sintering provides a record-breaking low temperature of barium cerate sintering (900°C). Having studied the effect of a microwave field on the microstructure of sintering products, we found that high-power microwave processing significantly reduces the average grain size of barium cerate ceramics.
Magneto-optical Properties of Small Atomic Clusters of Ga and In with As, V and Mn
Authors: Pozhar Liudmila A. , Yeates Alan T. , Szmulowicz Frank , Mitchel William C. 
Published: April 2011

AbstractThe Hartree-Fock (HF) method is used to synthesize virtually (i.e., fundamental theory-based, computationally) small stable atomic clusters of Ga and In with As and V, and an In-based cluster with As and Mn. The electronic energy level structures (ELSs), optical transition energies (OTEs), and charge/spin density distributions of these clusters have been analyzed. It has been shown that the spin of such clusters is collectivized, and that this collectivization is responsible for a dramatic drop in the clusters’ OTEs as compared to those of similar pyramidal clusters that do not contain “magnetic” atoms.
High-Permeability Particles for Magnetic Composites
Authors: Sailer Robert , Jeppson Pamela J , Jarabek Eric L , Sandstrom Joseph A , Al-Badri Zoha , Grier Dean G , Caruso Anthony N , Boudjouk Philip R , Eames Pete , Tondra Mark , Schulz Douglas L 
Published: April 2011

AbstractElectromagnetic shields and flux concentrators for magnetic sensors could utilize flexible and insulating composites applied using simple thin film deposition methods such as dip-coating, spin-coating, spraying, etc. As the first step towards development of composites with superior performance, efforts focused on isolating nanoparticles with large magnetizations under low fields. In this paper, we provide the results of proof-of-concept studies for two systems: metal-functionalized silicone-based materials (metal-silicone); and, Co-ferrite (Co2+1−xFe2+xFe3+2O4) nanoparticles. The metal-silicone materials studied included a polysiloxane that contained a pendant ferrocene where an optimum saturization magnetization of 5.9 emu/g (coercivity = 11 Oe) was observed. Co-ferrite nanoparticle samples prepared in this study showed unprecendented saturation magnetization (i.e., Ms > 150 emu/g) with low coercivity (Hc ∼ 10 Oe) at room temperature and offer potential application as flux concentrators.
Magnetometer based on the opto-electronic oscillator
Authors: Matsko Andrey , Strekalov Dmitry , Maleki Lute 
Published: April 2011

AbstractWe discuss properties of an all-optical self-oscillating magnetometer based on an opto-electronic oscillator stabilized with an atomic vapor cell. Proof of the principle DC magnetic field measurements characterized with 2 × 10−7 G sensitivity and 1 − 1000 mG dynamic range in one of the schemes are demonstrated.
Length Scale Effect on Deformation and Failure Mechanisms of Ultra-Fine Grained Aluminum
Authors: Hattar Khalid , Han J H , Follstaedt D M , Hearne S J , Saif T A , Robertson I M 
Published: April 2011

AbstractThe deformation and failure processes in ultra-fine and nanograined metals over different length scales have been probed using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) in combination with a micromechanical in situ straining device. This novel straining device affords the opportunity to directly correlate the macroscopic mechanical properties with the microscopic deformation and failure mechanisms. Through use of this device it has been shown that increased film thickness results in a transition between limited plasticity and intergranular fracture to global plasticity and shear failure for deposited aluminum samples of similar grain size but different thickness.
Mechanisms of Grain Growth in Free-Standing Nanograined Gold Thin Films
Authors: Gregg J. A. , Hattar K , Lei C H , Robertson I M 
Published: April 2011

AbstractRetention of the enhanced properties reported for nanograined metallic systems requires that the nanostructure be insensitive to temperature and deformation. In situ transmission electron microscopy annealing experiments were employed to investigate the structural changes associated with the formation of micron-sized grains in nanograined evaporated gold thin films. This abnormal grain growth occurs randomly throughout the film. Twinning but not dislocation slip occurs in the growing grains until the grain size is in the hundreds of nanometer range. The twins appear to hinder growth and for grain growth to continue the twins must either be annihilated or be able to grow with the grain concurrently.
Molecular Dynamics Simulations of Cluster-size Effect on Sputtering Process with Reactive Gas Cluster Ions
Authors: Aoki Takaaki , Matsuo Jiro 
Published: April 2011

AbstractTo investigate the size-effect of reactive clusters on sputtering processes, we performed molecular dynamics (MD) simulations of reactive cluster ions with various sizes impacting on solid targets. Various sizes of fluorine clusters, (F2)30, (F2)300 and (F2)3000, were irradiated on a Si(100) target at the same total incident energy of 6 keV. These clusters were irradiated on the same target one after another in order to reproduce real experimental conditions such as the accumulation of fluorine atoms in the target. The MD simulations of sequential cluster impacts enabled to perform various statistical analyses regarding the sputtered particles. The study of cluster size distributions showed that the sputtering process by reactive cluster ion impact has similarity with the emission from quasi-liquid materials excited to hyper-thermal conditions by ion bombardment. However, the major sputtered particles were different with each other; Si for (F2)30 (100 eV/atom), SiF2 for (F2)300 (10 eV/atom), and SiF3 for (F2)3000 (1 eV/atom). At the impact of a large size cluster with low incident energy, a large number of Si-F bondings were generated at the cluster-target interface surface, which enhances formation of volatile SiFx compounds with many fluorine atoms. In contrast, a small cluster with high kinetic energy-per-atom could cause the formation of numerous energetic surface atoms at the near surface region, which could be sputtered without being well fluoridated.
Analysis of Successive Focused Ion Beam Slices by Scanning Electron Imaging and 3D Reconstruction
Authors: Yeoh Terence , Ives Neil , Presser Nathan , Stupian Gary , Leung Martin , McCollum John , Hawley Frank 
Published: April 2011

AbstractAn antifuse structure was analyzed using scanning electron microscope imaging and focused ion beam image slicing to generate a form of three-dimensional microscopy. This method reveals nanometer scale features that could not be easily imaged using a single focused ion beam cross-section. A novel end-point detection technique has been developed to control the thickness of the slice to about 2 nm. Voxel imaging and interpretive three-dimensional reconstruction was used to resolve volumes as small as 2 cubic nm3. It was determined that the fusing region for an antifuse is a complex mixture of material phases with an elliptical volume approximately 75 nm in diameter.
Ion-Beam Enhanced Stress-Relaxation of SiGe on SiO2
Authors: Tanaka Masanori , Sadoh Taizoh , Ninomiya Masaharu , Nakamae Masahiko , Enokida Toyotsugu , Miyao Masanobu 
Published: April 2011

AbstractThe Ge condensation by oxidation of SiGe/Si-on-insulator (SOI) structures enabled highly stress relaxed SGOI. However, the relaxation rate obtained in the SiGe layers on insulator (SGOI) abruptly decreased with decreasing SiGe thickness below 50 nm. In order to enhance the relaxation rate in ultra-thin SGOI, the technique combined with H+ irradiation with medium dose (5×1015 cm-2) and post-annealing (1200°C) has been developed. It was demonstrated that highly relaxed (70 %) ultra-thin SGOI with low defect density (<106 cm-2) has been realized by this technique.
Self-assembled nano-dots of heteroepitaxial SiC on Si
Authors: Matsumoto Takashi , Kiuchi Masato , Sugimoto Satoshi , Goto Seiichi 
Published: April 2011

AbstractSelf-assembled silicon carbide (SiC) nano-dots were fabricated on Si wafers by an organometallic ion beam deposition. The self-assembled SiC nano-dots have the shape of a tile, and were heteroepitaxial SiC on Si.
Layer-by-Layer Sputtering and Ultrathin Ion Implantation by Low-Energy Grazing Ion Bombardment
Authors: Dzhurakhalov Abdurauf , Rahmatov Sirojiddin , Teshabaeva Nigorakhon , Yusupov Maqsud 
Published: April 2011

AbstractThe ion sputtering and implantation into GaAs(001) surface at 1-5 keV Se+ grazing ion bombardment have been investigated by computer simulation.The azimuth angular dependencies of sputtering and penetration yield at grazing incidence have been calculated. It was observed that these dependencies correlate the crystal orientation. The depth distributions of 1-5 keV Se ions implanted into GaAs(001) for several azimuth angles of incidence have been presented.
Chemical Behavior and Corrosion Resistance of Medical Grade Titanium after Surface Modification by Means of Ion Implantation Techniques
Authors: Schrempel Frank , Hildebrand Gerhard , Frant Marion , Wesch Werner , Liefeith Klaus 
Published: April 2011

AbstractThis work presents data on topographical structure, chemical surface composition, physicochemical properties and corrosion resistance of medical grade titanium after ion implantation. Pure commercial titanium has been implanted with 30 keV Na-, Ca- and P-ions at fluences of 2.0 × 1017 cm-2 and 1.5 × 1017 cm-2, respectively. Some of the samples were heat treated at 600 °C for 40 min. Atomic force microscopy (AFM) was used for surface analysis. The chemical composition was investigated using Rutherford backscattering spectrometry (RBS). Physicochemical investigations were carried out using contact angle measurements to determine the polarity of the modified titanium surfaces. Moreover, the electrokinetic zeta potentials on a physiological pH value have been determined. Finally, the corrosion resistance was examined in simulated body fluid (SBF) containing 4 g/l bovine serum albumin (BSA) using cyclic voltametry.Considering the P-implantations, the measured depth distribution of phosphorus agrees well with calculations. For the implantation of Na and Ca, the concentration of implanted atoms in the maximum of the depth distribution is noticeably lower and the distribution extends to larger depths compared to the predictions. This finding is associated with a strong incorporation of oxygen over the whole penetration depth of the implanted ions. According to topographical and chemical changes different contact angles as well as zeta potentials have been detected for the ion implanted surfaces compared to pure titanium. The electrochemical examinations indicate that the implantation has no negative influence on the corrosion resistance in comparison to unmodified medical grade titanium. The results show that ion implantation using certain ions can be used to design tailor-made titanium surfaces from a physicochemical point of view.
Ion irradiation-induced welding of a carbon nanotube to a Si (100) surface
Authors: Kotakoski Jani , Nordlund Kai 
Published: April 2011

AbstractCarbon nanotubes (CNTs) are one of the possible building blocks for electronic devices in the transition phase from traditional silicon-based microelectronics towards the few-nanometer regime. Remaining problems in integrating CNTs to the existing technology is the low reactivity of the CNT walls which leads to low conductance between CNTs and the other components. Because recent studies have shown that ion irradiation can be used to modify both the electrical and structural properties of CNTs, we propose that it could also be possible to use ion irradiation with low energies to enhance the conductance of these connections. We have used classical molecular dynamics simulations with empirically fitted potentials to examine this possibility by irradiating a single-walled carbon nanotube (SWCNT) on a silicon substrate at room temperature. The nanotube was deposited over a trench created to the silicon substrate so that the nanotube was partly suspended. Low irradiation doses and low energies (0.2 keV − 1.2 keV) were used to ensure that the irradiated CNT will not be destroyed. The simulations were carried out for silicon, carbon and neon ions. Our simulations indicate that ion irradiation will increase the number of covalent bonds between the CNT and the Si substrate. When the irradiation dose and energies are low, the damage caused to the SWCNT atomic network can be tolerable when compared to the improvement in the conductance of the contact regions. Furthermore, as the CNTs have high ability to heal the irradiation-induced damage, it is possible that the irradiation will not have a significant negative effect to the conductivity of the CNT in a system of this type.
High Aspect Ratio Microstructures in LiNbO3 Produced by Ion Beam Enhanced Etching
Authors: Schrempel Frank , Gischkat Thomas , Hartung Holger , Kley Ernst Bernhard , Wesch Werner , Tünnermann Andreas 
Published: April 2011

AbstractThis work presents data on damage evolution, volume expansion and etching behavior of LiNbO3 irradiated with Ar+-ions as a function of irradiation and etching conditions. Single crystals of x- and z-cut LiNbO3 were irradiated at room temperature and 15 K using Ar-ions with energies between 60 and 600 keV and ion fluences between 5 × 1012 and 1 × 1015 cm-2. The damage formation investigated with RBS channeling analysis depends on the crystal cut as well as on the irradiation temperature. Irradiation of z-cut material at 300 K causes complete amorphization at 0.4 dpa (displacements per target atom). In contrast 0.27 dpa are sufficient to amorphize the x-cut LiNbO3. Irradiation at 15 K reduces the number of displacements per atom necessary for amorphization to 0.18 dpa. To study the etching behavior ∼500 nm thick amorphous layers were generated via multiple irradiations with Ar+-ions. Etching was performed in HF-solution of different concentration and at different temperatures. The influence of the irradiation and etching conditions on damage formation and etching of LiNbO3 is discussed. In conclusion, negligible etching of the perfect crystal, high etching rates and high contrast of Ion Beam Enhanced Etching (IBEE) allow the realization of high aspect ratio microstructures in LiNbO3.
Surface Modification of Silicon Nano Mechanical Structures by Carbon Ion Implantation for Post-fabrication Transformation to Silicon Carbide
Authors: Virwani Kumar R , Sood Dinesh K , Elliman Robert G , Malshe Ajay P 
Published: April 2011

AbstractInternal stresses can cause de-lamination and fracture of coatings and structures and it is well known that ion-implantation can be used to control such behavior through modification of the stress. Here, however, we show that the unique ability of implantation to create controlled stresses in materials by altering both the chemical composition and mechanical properties, combined with an increase in the bending strength of materials, can used to create novel vertical nanostructures. Silicon cantilevers (beams), 193nm thick, 200nm wide and 3μm long, were implanted with carbon ions to create a buried SiCx layers. The internal stresses generated by implantation caused the beams to bend at angles ranging from 10 degrees to greater than 90 degrees, leading to unique vertical nanostructures. This method can be used to create 3-D nano electromechanical systems (NEMS).
Trans-disciplinary Graduate and Refresher Programs for Education, Research and Training in the Fields of Nanoscience and Nanotechnology
Authors: Itoh Tadashi , Akai Hisazumi , Ogawa Hisahito , Diño Wilson Agerico Tan , Ichikawa Satoshi 
Published: April 2011

AbstractNanoscience is an area that promises a new understanding of nature, while nanotechnology is the use of nanoscience to build new technologies that will change the world. It has captured the attention of the public, government, and industrial corporations. How it will influence our lives will depend on how we prepare ourselves and our successors. Here we present a brief outline of our effort of education, research and training being taken trans-disciplinarily at Osaka University since 2004, in order to prepare our future scientists, engineers, and industrial leaders in the rapidly flourishing fields of nanoscience and nanotechnology.