bluuebunny/crossref_metadata_2025_split huggingface dataset:
Porous Nickel Oxide Films for Electrochemical Capacitors
Authors: Liu Kuo-Chuan , Anderson Marc A. 
Published: April 2011

ABSTRACTNiO/Ni composite thin films consisting of nano-sized particles have been found to perform as good electrodes in electrochemical capacitor applications. These films can provide a specific capacitance of 25-40 F/g. The low cost of raw materials and easy manufacturing process of this system should allow one to produce low-cost electrochemical capacitors.
Amorphous Thin Film Ruthenium Oxide as an Electrode Material for Electrochemical Capacitors
Authors: Jow T.R. , Zheng J.P. 
Published: April 2011

ABSTRACTRuthenium oxide thin films of an amorphous phase were successfully prepared on a titanium (Ti) substrate at temperatures below 160 °C. The sol-gel process using metal alkoxide precursor in nonaqueous solvents was used to prepare these films. The preliminary results showed that a specific capacitance of 430 F/g can be achieved for amorphous ruthenium oxide electrode in sulfuric acid. Films prepared by this method are compared with the films prepared by the thermal decomposition of the aqueous ruthenium chloride solution at temperatures above 300 °C. The specific capacitance, the crystalline structure, and the surface morphology of these films as a function of the preparation temperature were also discussed.
A New Charge Storage Mechanism for Electrochemical Capacitors and Charge Storage Density Vs. Crystalline Structure of Metal Oxides
Authors: Zheng JP. , Jow T.R. 
Published: April 2011

ABSTRACTThe hydrous ruthenium oxide (RuO2.xH2O) powders with different contents of H20 have been formed by a sol-gel process and have been annealed at different temperatures. It was found that the specific capacitance of RuO2.xH2O is strongly dependent on the crystalline structure. The specific capacitance of over 720 F/g was obtained in an amorphous RuO2.xH2O. This value is at least two times greater than ever reported of this type of material.The specific capacitance dropped rapidly as the amorphous phase transforms into the crystalline phase at high temperatures. In contrast to the crystalline phase the specific capacitance of an amorphous RuO2.xH2O was not dependent on the specific surface area. The charge storage mechanism in amorphous RuO2.xH2O is different from that in the crystalline RuO2. The current in the cyclic voltammetric curve of RuO2.xH2O is nearly constant and is symmetrical with the potential in a range of 1 volts. The resistivity of pellets made from these powders is in the order of 10−3 Ω-cm.
Dependence of Battery Performance of Spinel Li1+XMn2O4 on the Preparation Method
Authors: Yoshio Masaki , Xia Yongyao , Ikeda Kazutaka , Noguchi Hideyuki 
Published: April 2011

ABSTRACTThe formation process of the spinel phase by the melt-impregnation method was extensively investigated by the pore volume distribution measurement. Two kinds of the spinel structure compounds Li1+xMn2O4 optimized in this method were examined as a 4V cathode in a lithium nonaqueous cell. The first one has an initial charge capacity of 135-147 mAh/g and an unstable rechargeability with the characteristic two-step process, and another one delivers a slightly lower capacity of 105-120 mAh/g and ideal rechargeability with the quasi-one step process. These compounds preserve a capacity of more than 110 mAh/g for the first 100 cycles. The capacity fading on cycling of the former spinel only occurs at the second charge plateau in the rage of x<0.4 in LixMn2O4, and is due to the unstable two-phase structure for lithium intercalation coexisting in this region. The excellent rechargeability for the later spinel results from a homogeneous reaction occurring over the entire intercalated region.
Sputter Roughening Instability on the Ge(001) Surface: Energy and Flux Dependence
Authors: Chason E. , Mayer T.M. , Kellerman B.K. 
Published: April 2011

AbstractWe have measured surface roughening kinetics during low energy Xe ion sputtering of Ge (001) surfaces. The results are interpreted in terms of an instability theory developed by Bradley and Harper [1]. Although the calculated magnitude of the roughening rate does not agree with the measured value, the variation of the rate with ion flux and energy is in agreement with the theory.
New Insight into Damage-Related Phenomena in Si Implanted Under Extreme Conditions
Authors: Holland O. W. , Nielsen Bent , Budai J. D. 
Published: April 2011

AbstractNew insight into damage formation in Si(100) during self-ion irradiation is gained from processing under extreme conditions. Dislocations form in the near-surface as a result of lattice relaxation in response to strain produced by precursor defects which are shown to be vacancy-type by positron analysis. A model to account for these defects and their distribution is presented. A novel technique is demonstrated which utilizes a subsequent implantation as a depth specific probe to manipulate the vacancy-type defects. Aspects of damage growth which emerge from the probe results are discussed.
Deposition of Lead-Silicate Glassy Thin Coatings by Rf Magnetron Sputtering: Correlation Between Deposition Parameters and Electrical and Structural Properties
Authors: Rigato V. , Maggioni G. , Boscarino D. , Della Mea G. 
Published: April 2011

AbstractThin films (100–400 nm) of lead silicate glass have been deposited by RF magnetron sputtering in Ar plasma at different discharge conditions. The interaction of the sputtered species with the gas atoms during the transport process through the discharge region and the kinetics of growth of the films have been investigated as a function of the target composition and of the substrate temperature. This study demonstrates the possibility of controlling the surface electrical resistance of the films in a wide range of values ranging from 1012 to 1017 during the film growth.
Ion Beam-Induced Changes in Optical Properties of MgO
Authors: Qian Ying , Ila D. , He K. X. , Curley M. , Poker D. B. , Boatner L. A. 
Published: April 2011

AbstractThe implantation of Ag into MgO (100) single crystals, followed by thermal annealing at 1100°C, leads to dramatic changes in their optical properties. The changes in the optical properties are due to the presence of small Ag clusters which are formed in the annealed samples. The small Ag clusters are obtained by thermal annealing of the implanted MgO crystals between 600°C and 1100°C to investigate the changes in cluster sizes and to correlate with changes in their optical properties. Sample characterization is carried out using optical spectrophotometry to confirm the effective presence of Ag clusters and Rutherford Backscattering Spectrometry (RBS) to study the profile of Ag clusters.
Ion-Beam-Assisted Deposition of Metal Nanocluster thin Films with Nonlinear Optical Properties
Authors: Cotell C. M. , Carosella C.A. , Flom S.R. , Schiestel S. , Haralampus N. , Barnett T. W. , Bartoli F.J. 
Published: April 2011

AbstractMetal nanocluster thin films (∼200 nm thickness) consisting of noble metal (Au) clusters (5-30 nm) in an active metal oxide (Nb2O5) matrix were deposited by evaporation or ion beam assisted deposition (IBAD). In some cases the films were given a post-deposition anneal. The microstructure of the films was examined by plan view and cross sectional transmission electron microscopy (TEM). The size of the metal nanoclusters was found to depend upon the temperature of the post-deposition anneal as well as the conditions of ion bombardment. Ion bombardment was found to stabilize smaller size particles. The linear optical properties of the films, as measured by VIS/UV spectroscopy, show particle size-dependent surface plasmon resonance effects. The nonlinear optical (NLO) properties of the nanoclusters in oxidized niobium were probed experimentally using degenerate four wave mixing (DFWM) and nonlinear transmission (NLT). The DFWM measurements yielded signals that showed strong evidence of saturation and give large values of χ(3)xxxxl. NLT measurements demonstrated that the nonlinear absorption coefficient and, hence, Imχ(3)xxxx was negative. Time resolved DFWM measurements exhibited dynamics that decayed on a several picosecond time scale. The magnitude and the picosecond dynamics of the NLO response were compared to those observed in gold nanoclusters formed by ion implantation in other media. The advantages of the IBAD method for fabricating third order NLO films include the ability to deposit films of arbitrary active region thicknesses and, more importantly, high cluster densities.
Titanium Nitride Formation by Low Energy Ar Ion Bombardment and UV-Light Irradiation During Deposition
Authors: Gerlach J.W. , Wengenmair H. , Stritzker B. , Rauschenbach B. 
Published: April 2011

AbstractTitanium nitride films were produced by a newly developed photon and ion beam assisted deposition system (PHIBAD system). With an electron beam evaporator titanium was deposited on silicon substrates in a controlled nitrogen environment. The growing δ-TiN films were bombarded with argon ions and illuminated with UV-light. The results demonstrate that the impurity content, the nitrogen to titanium ratio of the films, the microstructure and the crystal alignment are changed using UV-light irradiation during ion assisted deposition.
Deposition of Boron Nitride Coatings by Reactive Rf Magnetron Sputtering: Correlation Between Boron and Nitrogen Contents and the Flux of Energetic Ar+ Ions at the Substrate
Authors: Rigato V. , Spolaore M. , Della Mea G. 
Published: April 2011

AbstractThin films of BNxOy have been deposited by rf Reactive Magnetron Sputtering from a BN target in Ar+ plasma (1 Pa) at different substrate bias conditions. The possibility of obtaining dense and hard BN coatings at a target-to-substrate distance larger than the mean free path of the B and N atoms has been investigated.In order to deduce the plasma potential and the ion density near the substrates, the discharge characteristics have been measured by means of an electrostatic probe of the Langmuir type properly coupled to the glow discharge for avoiding the rf interference. From the probe data both flux and energy of the Ar+ ions have been determined and correlated to the net contents of boron and nitrogen as measured by means of the N(d,p) and 11Β(p,α) nuclear reactions. The results of this study show that in the investigated experimental conditions the flux of energetic Ar+ ions at the substrates is insufficient for promoting the formation of cubic BN as confirmed by XRD, FT-IR and nanohardness measurements. The reported data agree with recent literature findings and support the need of monitoring both the bombarding rate and energy of the Ar ions in rf discharges if the c-BN deposition is to be attained in a reproducible manner.
Ion Beam Reactive Sputter-Deposition of Silicon and Zirconium Oxides.
Authors: Pringle S.D. , Valizadeh R. , Colligon J.S. , Faunce C.A. , Kheyrandish H. 
Published: April 2011

AbstractOxides of silicon and zirconium have been deposited onto silicon, carbon and aluminium substrates by reactive sputtering using a 1 keV argon ion beam and a controlled partial pressure of oxygen. Using RBS, film composition was determined for a given partial pressure of oxygen and different Si or Zr deposition rates. There is evidence of retained argon in the film which is primarily due to argon ions reflected from the sputtered target. Cross-sectional TEM was used to examine the film microstructure and morphology. Both silica films and sub-stoichiometric zirconia films were found to be amorphous,whereas stoichiometric zirconia films were found to be polycrystalline with grain sizes in the range 10-20nm. A model has been developed to predict the composition of deposited films.
Tem and X-Ray Investigation of Single Crystal-Like Zirconia Films Fabricated by Dual Ion Beam Deposition
Authors: Ressler Kevin G. , Sonnenberg Neville , Cima Michael J. 
Published: April 2011

AbstractSingle crystal-like yttria-stabilized zirconia (YSZ) thin films have been deposited on amorphous quartz, polycrystalline zirconia, single crystal Si, and Hastelloy substrates using dual ion beam deposition (IBAD). These films are highly crystallographically aligned both normal to and within the film plane. The films are deposited at low substrate temperatures (<200°C), and the film orientation is substrate independent. θ-2θ X-ray diffraction, X-ray rocking curves, X-ray pole figures and X-ray phi scans are used to evaluate the film structure. High resolution cross-sectional TEM is used to examine the evolution of crystallographic film alignment on an amorphous quartz substrate. The data suggest that the evolution of biaxial alignment is nucleation controlled under these conditions.
Hyperthinning of Silicon and Sio2 for Low Power Electronic Applications
Authors: Oakes D.B. , Gelb A. , Green B.D. , Pirri A.N. , Wolfson R. 
Published: April 2011

AbstractSilicon-On-Insulator (SOI) and advanced device technologies require the ability to fabricate uniform thin films of silicon (< 50 nm) and silicon dioxide (< 5 nm). A technique for hyper-thinning silicon and silicon dioxide films to these dimensions is described. The method is based upon etching by a high flux beam of hyperthermal (2 to 14 eV translational energy) fluorine atoms generated using Physical Sciences’ FAST technology. The fluorine atom beam contains greater than 95% atoms and less than 0.1% ions. The low ion content of the beam allows damage-free processing of these films. At the available translational energies, the fluorine atom reaction probability with silicon is near unity. Hence, high rate etching can be achieved. Silicon films have been thinned at ambient temperature (20 C) to thicknesses less than 50 nm by this technique with etching rates up to 120 nm/min demonstrated. The hyperthinning is uniform and does not affect the surface finish. Analysis of the processed surface shows no evidence of contamination from the treatment. High rate etching of silicon dioxide films has also been shown. The reaction probability of hyperthermal fluorine atoms with SiO2 films is 0.25.
Synthesis of Thin Membranes in Si Technology by Carbon Ion Implantation
Authors: Serre C. , Pérez-rodríguez A. , Calvo-Barrio L. , Romano-RodríGuez A. , Morante J.R. , Esteve J. , Acero M.C. , Skorupa W. , Kögler R. 
Published: April 2011

AbstractThe use of high dose carbon ion implantation in Si for the production of ultrathin membranes is investigated. Carbon implantations with doses up to 1018 cm-8 and energies up to 300 keV, at room temperature and 500°C were used, followed by 10 hours annealing at 1150°C. Structural and chemical analysis has been performed (including TEM, XPS, Raman and IR spectroscopies), and the etch properties have been investigated for KOH and TMAH etchants. It is found that doses higher than 1017 cm-2 are needed to obtain efficient etch-stop layers in TMAH, independently of the annealing conditions, while in contrast with previous work, it was not possible to obtain satisfactory results using KOH. According to this, ultrathin crystalline membranes (below 500 nm thick) with average surface roughness as low as 4.8 nm, measured by AFM, were obtained, and the structural analysis revealed the formation of a highly stable buried layer of crystalline β-SiC precipitates aligned with the Si matrix. These results corroborate the ability of high dose C ion implantation to obtain buried layers usable for micomachining applications.
Diffusion, Precipitation, and Cavity-Wall Reactions of Ion-Implanted Gold in Silicon
Authors: Myers S.M. , Petersen G.A. 
Published: April 2011

AbstractThe diffusion of Au in Si and its binding to cavities and to precipitates of the equilibrium Au-Si phase were investigated in the temperature range 1023-1123 K using ion implantation and Rutherford backscattering spectrometry. The diffusivity-solubility product for interstitial Au was found to be about an order of magnitude greater than the extrapolation of previous, indirect determinations at higher temperatures. Chemisorption on cavity walls was shown to be more stable than Au-Si precipitation by 0.1-0.3 eV in the investigated temperature range, indicating that cavities are effective gettering centers for Au impurities.
Carbon Implantation in AlX Ga1−X As
Authors: Pearton S.J. , Abernathy C.R. 
Published: April 2011

AbstractMaximum hole densities of 4×1018 cm-3 were produced in Al0.3Ga0.7As by C+Ga implantation and subsequent annealing at ∼800°C. The activation efficiency decreases with increasing AlAs mole fraction and the use of higher temperatures for the Ga co-implantation, due to a reduced vacancy concentration under these conditions. The C diffusivity is ≤2×10−13 cm2sec−1 at 950°C in implanted Al0.3Ga0.7As, demonstrating that C is a much more thermally stable acceptor than Be, Mg, or Zn.
Optical and Electrical Properties of Heavily Carbon-Doped Gaas Fabricated by High-Energy Ion-Implantation
Authors: Shima Takayuki , Makita Yunosuke , Kimura Shinji , Harada Kentaro , Iida Tsutomu , Kotani Masanori , Osawa Akihumi , Shibata Hajime , Obara Akira , Kudo Kazuhiro , Tanaka Kuniaki , Kobayashi Eiichi , Hoshino Yasushi 
Published: April 2011

AbstractHigh-energy (400 keV) implantation of carbon (C) ions was made into LEC-GaAs substrates with C concentration ([C]) of 1019− 1022Cm−3. 2 K photoluminescence (PL) and Hall effect measurements indicated that activation rate of C in LEC GaAs is both optically and electrically extremely low even after furnace-annealing at 850 °C for 20 min. For [C] = 1×1022 cm−3, two novel strong emissions were obtained and PL measurements as a function of excitation power and sample temperature suggested that the two emissions one at 1.485 eV and the other at 1.305 eV should reflect the formation of a new alloy between GaAs and C. Dual implantation of C+ and Ga+ ions was carried out to improve the activation or substitution rate. We found that nearly 90% activation rate can be achieved for C dose of 2.2 × 1013 cm−2.
Ion Beam Assisted Quantum well Intermixing
Authors: Goldberg R. D. , Mitchell I. V. , Charbonneau S. , Poole P. , Koteles E. S. , Aers G. , Weatherly G. 
Published: April 2011

AbstractSignificant progress has been made in the past year in the use of high energy (MeV) ion irradiation to tune the bandgap and therefore emission wavelengths of single and multiple quantum well structures. These shifts are attributable to compositional mixing across the well and barrier layer interfaces, a process that is driven by the vacancy flux, released during the anneal stage, from radiation defects. We present data from a series of measurements in both GaAs- and InP-based QW structures to demonstrate the importance of the implantation parameters chosen (ion species, energy, flux, fluence and implant temperature). The dramatic difference in the response of these two systems with regard to the implant depth is believed to be associated with the very different diffusivities of the Gp III site vacancies. Prospects for implementing the irradiation approach as a spatially selective, planar process in integrated optoelectronic circuitry look very attractive and are illustrated for both passive and active components by reference to recent results from tuned wavelength lasers.
Suppression of Secondary Defects in Silicon by Carbon Implantation
Authors: Simpson Todd W. , Mitchell Ian V. 
Published: April 2011

AbstractWe have examined the role of co-implanted carbon in suppressing the formation of secondary defects in self-ion irradiated Si(100). Implantation of 540 keV energy Si ions to a fluence of 1015 cm-2 followed by a 900°C, 15 minute anneal leads to the growth of an extended defect band at the end-of-range. Range matched carbon co-implantation can be used to modify this defect development dramatically. While direct co-implantation of carbon and silicon ions has no apparent effect on the formation of extended defects, such formation can be suppressed when the implanted C is incorporated substitutionally into the silicon lattice. Ion channelling and nuclear reaction analysis show that substitutional carbon is removed from substitutional sites during Si ion irradiation. In this case, it is proposed that excess interstitial silicon ions which normally lead to the growth of secondary defects will occupy the lattice sites previously occupied by carbon ions.
Structural and Magnetic Properties of Ion Beam Deposited Ag(1−x)Fex Films
Authors: Khan H.R. , Loebich O. 
Published: April 2011

AbstractNanocrystalline granular films of compositions Ag75Fe25, Ag61iFe39 are deposited on Si (001) substrates by ion beam deposition technique. The structure of as deposited and annealed (400°C/0.3 h) films is investigated by X-ray diffraction and the lattice parameter of the Ag particles is determined. The size of the Ag-particles is estimated from the line broadening of Ag(111) reflection and Scherrer formula and the values are 9 and 16 nm before and after the heat treatment. The magnetic moment and the saturation magnetization of the Fe-particles are determined from the magnetic field dependent magnetization data and using the Langevin function. A relationship between the structure and magnetism is discussed.
Structure Of Ceria Overlayer On Zirconia Crystal Studied by Surface Diffraction
Authors: Dmowski W. , Fu S. , Egami T. , Gorte R. , Vhos J. 
Published: April 2011

AbstractWe have utilized white x-ray beam and a Ge solid state detector, in energy dispersive mode, to study the diffraction from the surface layers of ceria deposited on (001) surface of Y stabilized cubic zirconia with grazing incident beam. We found that ceria forms islands, oriented epitaxially with respect to the zirconia substrate, with a lateral coherence of the order of 60 Å.
Properties Variation with Composition of Single-Crystal Pb(ZrxTi1−x,)O3 Thin Films Prepared by MOCVD
Authors: Foster C. M. , Bai G.-R. , Li Z. , Jammy R. , Wills L. A. , Hiskes R. 
Published: April 2011

AbstractSingle-crystal thin films covering the full compositional range of Pb(ZrxTi1−x)O3(PZT) 0≤x≤1 have been deposited by metal-organic chemical vapor deposition (MOCVD). The films were grown on epitaxial, RF-sputter-deposited SrRuO3 thin film electrodes on (001) SrTiO3 substrates. X-ray diffraction (XRD), energy-dispersive electron spectroscopy (EDS) and optical waveguiding were used to characterize the crystalline structure, composition, refractive index, and film thickness of the deposited films. We found that the PZT films were single-crystalline for all compositions exhibiting cube-on-cube epitaxy with the substrate with very high degrees of crystallinity and orientation. We report the systematic variations in the optical, dielectric, polarization, and transport properties as a function of composition and the epitaxy-induced modifications in the solid-solution phase diagram of this system. These films exhibited electronic properties which showed clear systematic variations with composition. High values of remnant polarization (30–55 μC/cm2) were observed at all ferroelectric compositions. Unlike previous studies, the dielectric constant exhibited a clear dependence on composition with values ranging from 225–650. The coercive fields decreased with increasing Zr concentration to a minimum of 20 kV/cm at the (70/30) composition. In addition, these films exhibited both high resistivity and dielectric-breakdown strength (˜1013 Ω-cm at 100 kV/cm and >300 kV/cm, respectively) without any compensative doping.
Optical Waveguides Using Epitaxial Bi4Ti3O12 Thin Films on MgO with CeO2 Cladding Layers
Authors: Jo William , Noh T. W. , Byun Y. T. , Kim S. H. 
Published: April 2011

AbstractCeO2 thin films were grown on MgO(001) single-crystal substrates by pulsed laser deposition. The CeO2 thin films were used as a cladding layer of a Bi4Ti3O12 thin film waveguide. Structural properties of the BTO/CeO2/MgO heterostructures were investigated using x-ray diffraction techniques. An epitaxial relationship of BTO(001)//CeO2(001)// MgO(001) and BTO[100]//CeO2[100]//MgO[001] was confirmed. From the epitaxial heterostructure, a ridge waveguide was fabricated by photolithographic and ion-milling techniques. An single-mode near-field pattern was observed using an end-fire coupling method.