bluuebunny/crossref_metadata_2025_split huggingface dataset:
Room Temperature Fabricated ZnO:Al with Elevated and Unique Light-Trapping Performance
Authors: Johnson E. V. , Charpentier C. , Emeraud T. , Lerat J.F. , Boniface C. , Huet K. , Prod’homme P. , Roca i Cabarrocas P. 
Published: September 2011

ABSTRACTWe present a novel ZnO:Al fabrication process consisting of room-temperature vacuum sputtering followed by an excimer laser annealing (ELA). The ELA treatment improves the optical transmission of the films, and the film resistivities (<1 mΩ·cm) remain stable or improve with increasing laser fluence up to 0.6 J/cm2, as the carrier density increases but the carrier mobility is degraded. This process is followed by a standard dilute HCl chemical texturing step, and produces substrates with suitable texture, conductivity, and transparency properties for thinfilm photovoltaic applications. Substrates resulting from this process display elevated haze levels (80% at 600 nm and 50% at 800 nm) after the wet-chemical etching step. Such substrates have been used to make single junction hydrogenated nanocrystalline silicon solar cells, and an increase in the short-circuit current of up to 2.2 mA/cm2 is observed compared to a substrate deposited by a standard room-temperature sputtering + wet-etch process. This gain is primarily due to increased photo-response in the red due to improved light-scattering, as at wavelengths greater than 600 nm, a gain in photocurrent of up to 1.7 mA/cm2 is observed.
Current Collecting Grids for R2R Processed Organic Solar Cells
Authors: Abbel Robert , van den Boomen Jaquelien , van Lammeren Tim , de Koning Tom , Valeton Josué J. P. , Meinders Erwin R. 
Published: September 2011

ABSTRACTExposure to highly focussed flash light (photonic flash sintering) has been developed as a technology to successfully cure printed metal inks on temperature sensitive plastic substrates. In contrast to the traditional approach of thermal oven sintering, conductivities up to 30 % of the value of bulk silver can be achieved within a few seconds without foil deformation. The compatibility of this technology with R2R production has been demonstrated with line speeds up to 5 m/min. As a consequence, our approach is expected to enable the high throughput fabrication of current collecting grids for organic solar cells in order to replace transparent electrodes based on metal oxides such as ITO. Additionally, our new sintering technology has enabled us to process a new generation of conductive inks, based on copper complexes, which cannot be processed by oven sintering.
Effect of Working Distance on Properties of Sputtered Molybdenum Films
Authors: Pethe Shirish A. , Kaul Ashwani , Dhere Neelkanth G. 
Published: September 2011

ABSTRACTMolybdenum back contact deposition is a bottleneck in high volume manufacturing due to the current state of art where multi layer molybdenum film needs to be deposited to achieve the required properties. In order to understand and solve this problem experiments were carried out. The effect of working distance (distance between the target and the substrate) on film properties was studied and is presented in this work. Earlier work carried out at Florida Solar Energy Center reflected on the effect of the sputtering power and working gas pressure on the film properties. This work is continuation of that effort in understanding effects of various sputtering parameters and determining the possible route to develop single layer molybdenum films with the required properties of near zero stress, low resistivity and good adhesion to substrate.
Transmission electron microscopy of misfit dislocation and strain relaxation in lattice mismatched III-V heterostructures versus substrate surface treatment
Authors: Wang Y. , Ruterana P. , Desplanque L. , El Kazzi S. , Wallart X. 
Published: September 2011

ABSTRACTHigh resolution transmission electron microscopy in combination with geometric phase analysis is used to investigate the interface misfit dislocations, strain relaxation, and dislocation core behavior versus the surface treatment of the GaAs for the heteroepitaxial growth of GaSb. It is pointed out that Sb-rich growth initiation promotes the formation of a high quality network of Lomer misfit dislocations that are more efficient for strain relaxation.
Infrared Studies of the (1-x) PbTe – (x) PbSnS2 System
Authors: Hasapis Thomas C. , Girard Steven N. , Hatzikraniotis Euripides , Paraskevopoulos Konstantinos M. , Kanatzidis Mercouri G. 
Published: September 2011

ABSTRACTIn this work we report on the infrared properties of the thermoelectric (1-x)PbTe-xPbSnS2 system with x=0.03, 0.06, 0.11 and 0.33. The results obtained by the analysis of the reflectivity spectra are discussed together with the structural and morphological characteristics obtained by XRD and SEM-EDS measurements. The system was found macroscopically homogeneous for x=0.03 and x=0.06 and phase separated for x=0.11 and x=0.33. The analyzed ~150cm-1 PbS impurity mode demonstrated a composition close to the PbTe0.98S0.02 for the major phase. The incorporation of PbSnS2 causes a reduction in plasma frequency (decrease in carrier frequency concentration) and an increase in carrier mobility.
Optimizing Stressor Film Deposition Sequence in Polish Rate Order for Best Planarization
Authors: Zhang John H , Xiao Changyong , Strane Jay W , Venigalla Rajasekhar , Economikos Laertis , Hall Lindsey , Chen Jie , Stoll Derek C , Wallner Jin , Zhuang Haoren , Ferreira Paul , Kleemeier Walter , Goldberg Cindy , Moon Yongsik , Truong Connie , Sudijono John , Chen Xiaomeng , Sampson Ron 
Published: September 2011

ABSTRACTChemical Mechanical Polish (CMP) is one of the key technologies for the development of modern high performance integrated circuits. The requirements for the CMP uniformity get extremely demanding in order to meet the litho requirements for 32nm technology node and beyond. In this paper, two kinds of orders related to the stressor films that affect the CMP uniformity are revealed. The first is the stressor films deposition order according to the CMP polish rate of each stressor film. The second is the stress gradients order that formed inside the films sitting on top of the stressors. Through the optimization of the order, we show successfully removal of couple hundreds angstroms stressor step heights within 300mm wafer range. The method developed here can also find applications in microelectromechanical systems and 3D integration circuits.
Complementary Resistive Switches (CRS): High speed performance for the application in passive nanocrossbar arrays
Authors: Rosezin Roland , Linn Eike , Nielen Lutz , Kügeler Carsten , Bruchhaus Rainer , Waser Rainer 
Published: September 2011

ABSTRACTIn this report, the fabrication and electrical characterization of fully vertically integrated complementary resistive switches (CRS), which consist of two anti-serially connected Cu-SiO2 memristive elements, is presented. The resulting CRS cells are initialized by a simple procedure and show high uniformity of resistance states afterwards. Furthermore, the CRS cells show high switching speeds below 50 ns, making them excellent building blocks for next generation non-volatile memory based on passive nanocrossbar arrays.
Thick Beryllium Coatings by Magnetron Sputtering
Authors: Xu H. , Alford C. , Chason Eric , Detor A. , Fuller T. , Hamza A. , Hayes J. , Moreno K.A. , Nikroo A. , van Buuren T. , Wang M. , Wu J. , Youngblood K.P. 
Published: September 2011

ABSTRACTThick (>150 μm) beryllium coatings are studied as an ablator material of interest for fusion fuel capsules for the National Ignition Facility (NIF). As an added complication, the coatings are deposited on mm-scale spherical substrates, as opposed to flats. DC magnetron sputtering is used because of the relative controllability of the processing temperature and energy of the deposits. We used ultra small angle x-ray spectroscopy (USAXS) to characterize the void fraction and distribution along the spherical surface. We investigated the void structure using a combination focused ion beam (FIB) and scanning electron microscope (SEM), along with transmission electron microscopy (TEM). Our results show a few volume percent of voids and a typical void diameter of less than two hundred nanometers. Understanding how the stresses in the deposited material develop with thickness is important so that we can minimize film cracking and delamination. To that end, an in-situ multiple optical beam stress sensor (MOSS) was used to measure the stress behavior of thick Beryllium coatings on flat substrates as the material was being deposited. We will show how the film stress saturates with thickness and changes with pressure.
Multicolor Luminescence from Ca3Y2(SiO4)3:Eu2+,Eu3+ Material
Authors: Dobrowolska Anna , Zych Eugeniusz 
Published: September 2011

ABSTRACTCa3Y2(SiO4)3 powder activated with Eu was prepared with ceramic method. Its spectroscopic properties in VUV-UV-Vis region together with structure and morphology were analyzed. Luminescence measurements indicated that Ca3Y2(SiO4)3 prepared in a reducing atmosphere contained both Eu2+ and Eu3+ ions. The excitation could be tuned to generate a complex luminescence consisting of a broad band related to a blue-greenish 5d → 4f emission of Eu2+ and 4f → 4f red luminescence of Eu3+. Their superposition covered the whole visible part of spectrum and appeared almost white among others upon excitation around 390 nm.
Laser-treated Parchment Paper: An Inexpensive Microfluidic Platform
Authors: Chitnis Girish , Ding Zhenwen , Chang Chun-Li , Savran Cagri A. , Ziaie Babak 
Published: September 2011

ABSTRACTIn this paper, we report on a method for fabricating an inexpensive microfluidic platform on parchment paper. Parchment paper was selected for this purpose due to its wide availability for culinary applications and hydrophobic silicone-based surface coating. We were able to selectively modify the surface structure and property (hydrophobic to hydrophilic) using a CO2 laser. The modified surface has highly-porous structure which helps to trap chemical and biological reagents for analysis. The treated surface is stable over time and can be used for aqueous droplet assembly. Finally, we demonstrated the applicability of this platform for performing chemical reaction using luminol-based hemoglobin detection.
Microstructural characterization of GaAs-AlxGa1-xAs core-shell nanowires grown by Au-catalyst assisted MOVPE
Authors: Altamura D. , Miccoli I. , Prete P. , Lovergine N. , Tapfer L. 
Published: September 2011

ABSTRACTIn this work, we report on the microstructural and morphological characterization of III-V semiconductor nanowires (NWs) epitaxially grown on (111)B-GaAs substrates by Au-catalyst assisted metalorganic vapor phase epitaxy. As-grown dense (108-109 cm-2) arrays of few-micron long vertically-aligned (i.e. parallel to the <111> crystallographic axis) GaAs, AlxGa1-xAs and core-shell GaAs-AlxGa1-xAs NWs were investigated, carrying out HRXRD measurements on different (hkl) reflections and by recording reciprocal space maps (RSMs) around the materials (111) reciprocal lattice points (relps). We show that NW diffraction peaks are visible in the RSM by means of characteristic halos. In the case of GaAs NWs, the halo is located at the (111) relp indicating that the NWs are grown along the <111> direction and parallel to the <111> axis of the GaAs substrate. On the contrary, for AlxGa1-xAs NWs or intentional core-shell GaAs-AlxGa1-xAs NWs the halo is displaced (along the momentum transfer normal to the surface, Qz) with respect to the GaAs (111) relp due to the elastic lattice strain associated with the compositional variation, e.g. the Al molar fraction in the AlxGa1-xAs alloy, within the nanostructures.
Co2+ ions-containing ordered silica monoliths: Influence of the copolymer P123/Si and Co2+ ions/Si ratios on the organization of the monoliths
Authors: Delahaye Emilie , Aouadi Merwen , Durand Dominique , Beaunier Patricia , Fornasieri Giulia , Bleuzen Anne 
Published: September 2011

ABSTRACTAmong the different possibilities to control the size, the shape and the spatial organization of nano-objects, one consists in the use of the ordered mesoporosity of silica matrices as nanoreactors for their synthesis. This strategy has been used to elaborate Prussian Blue Analogues (PBA) exhibiting photomagnetic properties. Since the synthesis of these nanocomposites begins with the obtention of mesoporous silica monoliths containing Co2+ ions, we focus in this paper on the effect of the quantity of Co2+ ions and the amount of surfactant on the nanostructuration of these monoliths.
Functional and Functionalized Silicate Materials
Authors: Johnson Brandy J. , Melde Brian J. , Lin Baochuan , Charles Paul T. , Malanoski Anthony P. , Nasir Mansoor 
Published: September 2011

ABSTRACTMesoporous organosilicate materials combine tunable binding characteristics, high surface area, and low materials density with an ordered pore network. Surface modifications provide the potential for incorporation of a variety of functional groups. We have taken advantage of these characteristics for the development of a range of materials to be utilized in various applications. In one approach, porphyrins are incorporated into the materials to provide unique catalytic properties. In these materials, the organosilicate scaffold stabilizes the porphyrin catalyst and facilitates interaction of the catalyst and target. Catalysis can be stimulated through exposure to light or application of an electrical current. The selectivity of the materials can be influenced through choice of organic bridging groups in the organosilicate structure and through selection of the porphyrin component. In addition, a type of molecular imprinting can be applied to provide sites on the pore walls that enhance adsorption selectivity for the target. These materials are directed at the development of self-decontaminating surfaces and coatings. Similar materials characteristics have been utilized in the development of solidphase extraction materials for use in the pre-concentration of nitroenergetic targets from ground and surface water samples. These materials are being incorporated into systems for in situ water quality monitoring. Mesoporous organosilicates can also be applied to the encapsulation of proteins and nucleic acids, stabilizing them for wider application of technologies utilizing these reagents. Modifications to the pore surfaces, in this case, are used to incorporate stabilizing agents such as sugars and proteins which should extend shelf-life and reduce storage restrictions.
Influence of near-surface and volume real structure on the electronic properties of SrTiO3 MIM structures
Authors: Seibt J. , Hanzig F. , Strohmeyer R. , Stoecker H. , Himcinschi C. , Abendroth B. , Meyer D. C. 
Published: September 2011

ABSTRACTPerovskite-type transition metal oxides have great potential as storage material in resistive random-access memory (RRAM) devices. Typical non-volatile memory cells are realized in metal-insulator-metal (MIM) stacks with insulator thicknesses of few nanometers. We report on the investigation of single-crystal SrTiO3 to understand the role of volume and interface real structure for the electrical conductivity in such materials. Conductivity in SrTiO3 single crystals was established by a reducing high vacuum (HV) annealing introducing charged oxygen vacancies acting as donor centers. Titanium electrodes are evaporated on both crystal faces to obtain an MIM element.
The Absorption of Diamondoids from Time-dependent Density Functional Calculations
Authors: Vörös Márton , Demjén Tamás , Gali Adam 
Published: September 2011

ABSTRACTDiamondoids are small diamond nanocrystals with perfect hydrogenated surfaces. Recent absorption measurements showed that the spectrum of diamondoids exhibit features that are not understood from the theoretical point of view, e.g. optical gaps are only slightly larger than the gap of bulk diamond which runs against the quantum confinement effect. Previous calcula-tions, even beyond standard density functional theory (DFT), failed to obtain the experimental optical gaps (Eg) of diamondoids. We show that all-electron time-dependent DFT (TD-DFT) calculations including the PBE0 hybrid functional in the TD-DFT kernel are able to provide quantitatively accurate results. Our calculations demonstrate that Rydberg transitions govern the low energy part of the absorption spectrum, even for relatively large nanodiamonds result-ing in low Eg. Since the optical gap of these diamondoids lies in the ultraviolet spectral re-gion, we investigated whether simple adsorbates of the surface are able to shift the gap towards the infrared region. We found that a double bonded sulfur atom at the surface results in a sub-stantial gap reduction.
Ferromagnetism in undoped semiconductors
Authors: Ma Yandong , Dai Ying , Huang Baibiao 
Published: September 2011

ABSTRACTThe so-called “d0” magnetism observed in semiconductors, which is not caused by partially filled d orbitals, has challenged our conventional understanding on the origin of magnetism. One class of semiconductor materials showing d0 ferromagnetism is undoped oxides and nitrides. Here, we review the ferromagnetic properties of undoped GaN and MgO based on our recent investigations. It is revealed that the room-temperature ferromagnetism originates from the anion dangling bonds associated with the surface cation-vacancies. And the magnetism of ferromagnetic coupling between the vacancy induced local magnetic moment by through-bond spin polarization in undoped semiconductors is reviewed according to our works.
Magnetic Properties of Polar ZnO Surfaces from Ab-initio Calculations
Authors: Fischer Guntram , Sanchez Nadiezhda , Adeagbo Waheed A. , Lüders Martin , Szotek Zdzislawa , Temmerman Walter , Ernst Arthur , Hergert Wolfram , Muñoz M. Carmen 
Published: September 2011

ABSTRACTWe have studied the effect that applying self-interaction correction (SIC) to oxygen p orbitals has on the magnetic moment formation of three polar ZnO surfaces; all of them being oxygen terminated. For these investigations we have used a multi-code approach. This has allowed us, on the one hand, to relax the surface structure using the pseudopotential code SIESTA. On the other hand, by using the obtained relaxed structures for calculations within the KKR Green’s function formalism, we have been able to apply SIC and use the magnetic force theorem for calculating Heisenberg exchange parameters. The latter contain information about both the strength of the interaction and the interaction mechanism.Our calculations show that all three surfaces are magnetic. In addition, we find that applying SIC is necessary to correctly describe the top oxygen atom of the (0001)-t and (0001)-h surfaces.
Isocyanate-Derived Organic Aerogels: Polyureas, Polyimides, Polyamides
Authors: Leventis Nicholas , Sotiriou-Leventis Chariklia , Chandrasekaran Naveen , Mulik Sudhir , Chidambareswarapattar Chakkaravarthy , Sadekar Anand , Mohite Dhairyashil , Mahadik Shruti S. , Larimore Zachary J. , Lu Hongbing , Churu Gitogo , Mang Joseph T. 
Published: September 2011

ABSTRACTWe describe organic aerogels derived from multifunctional isocyanates through reaction with water (polyureas), acid andydrides (polyimides) and carboxylic acids (polyamides). All processes are invariably single-step, one-pot and take place at room or slightly elevated temperatures. The resulting materials are robust, their density may vary over a very wide range and their nanomorphology can be either particulate or fibrous, but in all cases they all consist of similarly sized primary particles.
Polar-fluoropolymer Blends for High Energy Density Low Loss Capacitor Applications
Authors: Wu Shan , Lin Minren , Lu David S-G. , Zhang Qiming 
Published: September 2011

ABSTRACTBesides energy density, the electric loss at high electric fields is another major concern for many capacitor applications. This paper presents recent works in developing high energy density low loss polymer capacitors. In order to reduce the dielectric loss while maintaining high energy density in poly(vinylidene fluoride-hexafluoropropylene) P(VDF-HFP) and P(VDF-CTFE) (CTFE: Chlorotrifluoroethylene) based polymers, a polymer blend approach was investigated. We show that by blending P(VDF-CTFE) with a proper low loss polymer such as poly(ethylene- chlorotrifluoroethylene) (ECTFE) can lead to marked improvement in the loss of dielectric films. In this study, P(VDF-CTFE) blends films with different wt% of ECTFE have been examined to find a balance between dielectric constant and the loss. In addition, crosslink in the blends has been employed to further improve the dielectric performance of the blends. The results indicate that these blends exhibit an excellent performance: relatively high dielectric constant (~ 6~7) and low loss (~ 0.01) at 1 kHz. For the crosslink blend films, the high field loss is reduced to below 5% with a discharged energy density 4.3 J/cm3 under a field of 300 MV/m.
Thermo-mechanical Behavior of (Meth)Acrylate Shape-Memory Polymer Networks
Authors: Frick Carl P. , Lakhera Nishant , Yakacki Christopher M. 
Published: September 2011

ABSTRACTOur overall approach is based on developing a photocrosslinkable polymer network with a favorable shape-memory response, using polymer chemistry and crosslinking density to control thermo-mechanical properties. Three polymer networks were created and thermo-mechanically tested, each from tert-Butyl acrylate linear builder co-polymerized with a poly(ethylene glycol) dimethacrylate cross-linker. By systematically altering the molecular weight and the weight fraction of the cross-linker, it was possible to create three polymers that exhibited the same glass transition temperature, but varied by almost an order of magnitude in rubbery modulus. Therefore, the mechanical stiffness could be tailored to suit a given application. Recovery behavior of the polymers was characterized over a range of deformation temperatures. It has been implicitly assumed a linear relationship between Free-Strain (i.e. no actuation force) and Fixed-Stress (i.e. maximum actuation force), however, this has never been confirmed experimentally. The energy per unit volume performed by the shape-memory polymer was quantified, and observed to be a function of strain recovered. The maximum recoverable work was shown to increase with cross-linking density, although the overall efficiency is similar for all materials tested.
Development of a dual growth factor loaded biodegradable hydrogel and its evaluation on osteoblast differentiation in vitro
Authors: Dyondi Deepti , Webster Thomas J , Banerjee Rinti 
Published: September 2011

ABSTRACTHydrogels with their tunable properties are attractive candidates for developing tissue engineering scaffolds for various applications (including bone and cartilage). The current work involved studying the synergistic effect of basic fibroblast growth factor (bFGF) and platelet derived growth factor BB (PDGF-BB) entrapped within injectable porous gels for bone regeneration applications. An in situ gelling system was developed using bacterial polysaccharides gellan and xanthan gum by temperature and ionic gelation with Ca+2. After the initial characterization of the hydrogels, a dual growth factor release system was developed wherein growth factors were encapsulated within chitosan nanoparticles embedded in the gels as well as directly within the gel. The hydrogel structure was characterized by SEM and TEM and in vitro growth factor release studies showed a slow release profile in PBS. Further, human fetal osteoblasts were entrapped within the hydrogel and a 21 day osteoblast differentiation study was conducted. An improvement in osteoblast total protein synthesis and collagen content was observed by day 21 compared to control gels without growth factors. Although further evaluation regarding mechanical properties and expression of osteogenic differentiation marker genes will be necessary, the present study suggests that injectable scaffolds can be used for the delivery of multiple growth promoting agents to support osteoblast differentiation.