bluuebunny/crossref_metadata_2025_split huggingface dataset:
Competitive Adsorption of Lung Surfactant and Serum Proteins at the Air-Liquid Interface: A Grazing Incidence X-Ray Diffraction Study
Authors: Stenger Patrick C , Wu Guohui H , Chi Eva Y , Frey Shelli L , Lee Ka Yee C , Majewski Jaroslaw , Kjaer Kristian , Zasadzinski Joseph A 
Published: April 2011

AbstractThe competitive adsorption of lung surfactant (LS) and albumin at the air-liquid interface and the ability of polyethylene glycol (PEG) to mediate LS adsorption are analyzed using pressure area isotherms and grazing incidence x-ray diffraction (GIXD). The addition of albumin drastically reduces the amount of LS on the interface and slightly increases the LS lattice spacing. The addition of PEG restores the characteristic LS peaks, yielding a slightly more compact lattice. The scattering results are consistent with recent work which proposed that albumin creates a physical barrier which eliminates LS adsorption and that PEG enhances LS adsorption but does not significantly change LS surface ordering.
ALL-ORGANIC FLEXIBLE AND TRANSARENT AMBIPOLAR FETs WITH ORGANIC BULK HETEROJUNCTIONS
Authors: Cosseddu Piero , Bonfiglio Annalisa , Salzmann Ingo , Rabe Jurge P. , Koch Norbert 
Published: April 2011

AbstractWe report on the realization of flexible and transparent all-organic Ambipolar Field Effect Transistors. The devices were assembled on a flexible plastic foil, i.e. Mylar®, and the contacts were realized with poly(ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and patterned by means of Soft Lithography, MicroContact Printing (μCP). As semiconductor layer we used organic bulk heterojunctions of pentacene/C60 realized either by co-deposition of the two different molecules or by a double layer structure in which pentacene was used as buffer layer at the interface with the gate dielectric. Interestingly, all devices (co-deposited and double layer), measured in air, worked in accumulation mode as ambipolar OFETs, however some interesting differences between the two structures can be pointed out. Supported by Atomic Force Microscopy, we demonstrated that growing C60 on a pre-deposited pentacene buffer layer leads to a clear improvement in the morphology and crystallinity of the deposited film allowing to improve n-type conduction by two orders of magnitude. This work is particularly interesting because on one hand it confirms the importance of the substrate properties for the ordered growth of organic semiconductors, which determines the transport properties of organic materials; moreover, it demonstrates, also for n-type and ambipolar transistors, the possibility of avoiding problems normally associated to metal contacts: the lack of mechanical robustness, flexibility, and the unfeasibility of realizing contacts with low cost techniques like printing or soft lithography. The flexibility and transparency of the final OFET structure and the simple low cost fabrication technique employed pave the way for an economic mass production of large area transparent “Plastic Electronics”.
Metal Suppression of Pentacene Grain Growth
Authors: Lo Hsi-wen , Tai Yu-Chong 
Published: April 2011

AbstractPentacene thin-film transistors use either bottom-contact or top-contact electrodes. Transistors with bottom-contact electrodes are fabricated in such a way that metal is deposited and patterned before pentacene deposition while those with top-contact electrodes are fabricated in reverse order. Hole mobility is closely related to pentacene grain sizes and grain sizes of pentacene depend heavily on the surface roughness. When the surfaces are flat and smooth enough, the grains of pentacene are still small if metal is deposited before pentacene, i.e., bottom-contact configuration. Pentacene inside the channels formed by source and drain electrodes has much smaller grains than those far away from metal electrodes.To further understand this phenomenon, we first studied pentacene grain growth on different substrates (oxide, Poly-4-vinylphenol or PVP, and SU8-2.) but with same metal electrodes (500 Ö Au). Next, we studied pentacene grain growth on the same substrate (oxide) but with different metal electrodes (500 Ö Au, 500 Ö Al, and 500 ÖCr). To avoid contaminating and damaging substrate surfaces, we used shadow masks for metal deposition.For substrate studies, the fabrication process of testing samples began by oxidation of silicon wafers. PVP and SU8-2 were spin-coated on oxide wafers and cured. 500 Ö Au was thermally evaporated through shadow masks onto wafers to form source and drain. Pentacene was then thermally evaporated onto the wafers.Likewise, the fabrication process of the second study began by oxidation of silicon wafers. Different metals were thermally evaporated through shadow masks onto oxide wafers. Finally, pentacene was thermally evaporated onto the wafers.To further study the relation between pentacene grain sizes and distance from metal electrodes, we also made metal ring structures. The substrates were kept at room temperature during pentacene deposition for all samples.Grain diameters were calculated from scanning probe microscopic or atomic force microscopic images. Images taken with Veeco Digital Instrument Dimension 3100 AFM were analyzed with Scion Image program. After counting particle numbers, average grain diameters were calculated assuming grains are circular.Our data show that pentacene has drastically smaller grains inside the channels electrodes than that far away electrodes for all 3 kinds of substrates: oxide, PVP and SU8-2. EDS spectrum confirms that there is no Au inside the channels. Not only Au, but also Al and Cr show the same phenomenon. Across the 400-um metal rings, pentacene grain diameters increase first and then decrease, confirming that pentacene grain growth is somehow suppressed by the presence of metal.This phenomenon adds another reason supporting that pentacene thin-film transistors with bottom-contact electrodes have worse performances due to smaller grains. Currently, we are working on modeling this phenomenon and finding theoretical explanations.
Planarization Materials for Active Matrix Thin Film Transistor Arrays
Authors: Krishnamoorthy Ahila , Spear Richard , Gebrebrhan Amanuel , Stifanos Mehari , Bien Hai , Lowe Marie , yellowaga Deborah , Smith Peter 
Published: April 2011

AbstractTraditional plasma based dielectric films are conformal and cost-prohibitive for large displays. Solution based dielectrics are planarizing in nature and provide a flat surface for indium tin oxide (ITO) layer with the resultant uniform liquid crystal response throughout the pixel. In this paper, we present the display-related material properties and integration results obtained by using a solution-based organosilsesquioxane material. The material exhibits extremely high transmittance and planarization, low outgassing, high resistance to moisture absorption and diffusion, good adhesion to other layers integrated with it and ease of integration.
Electro-Fragmentation Analysis of Dielectric Thin Films on Flexible Polymer Substrates
Authors: Pinyol Albert , Meylan Bastian , Gilliéron Damien , Mottet Aurélie , Mewani Vinodh , Leterrier Yves , Månson Jan-Anders E 
Published: April 2011

AbstractA novel electro-fragmentation method was developed as a fast alternative to the time consuming fragmentation test carried out in situ in a microscope, to investigate the failure of dielectric coatings on polymer substrates using an ultrathin conductive layer. Focus was put on SiNx coatings on polyimide substrates. A careful selection of the conductive layer was carried out to avoid artifacts resulting for instance from a change of the residual stress state of the investigated coating. Au layers were found to be too ductile and Al-Ti layers altered the stress state of the nitride, which invalidated their use to probe the failure of the nitride coatings. In contrast, a 20 nm thick graphite layer was found to accurately reproduce the failure of the nitride, which was analyzed in terms of residual strain and cohesive properties of the graphite layer. An electro-fatigue device was built and preliminary results suggest that damage already develops in ultrathin coatings at relatively low strain levels under long-term fatigue loading.
Fabrication of Conductive Polymeric Arrays using Direct Laser Interference micro/nano Patterning
Authors: Lasagni Andrés Fabian , Acevedo Diego , Barbero Cesar , Muecklich Frank 
Published: April 2011

AbstractThin films of polyaniline (PANI) deposited onto different substrates were nano-structured using direct laser interference patterning (DLIP) at room temperature and pressure in air atmosphere. Regular line-like arrays with thicknesses up to 600 nm were fabricated by means of this technique in only one single step. The activity of the remained polyaniline was determined by monitoring its doping level using Energy Dispersive X-Ray Analysis (EDX), while its chemical structure was confirmed by Fourier Transform Infrared Spectroscopy using Attenuated Transmission Reflectance (FTIR-ATR). The structuring mechanisms of PANI supported in both polycarbonate (PC) and polyimide (PI) films were demonstrated using cross-sectional analyses performed with a dual-beam workstation (FIB/SEM Tomography). Moreover, by varying the fluence of the laser beam, it is possible to control the width of the PANI arrays, and large areas (mm2 - cm2) could be patterned. Additionally, electrical resistance measurements of the individual PANI strips demonstrated that electrical properties of unmodified regions remain unchanged.
Two-step Defect Reduction of GaAs/Si Epitaxy by Selective Aspect Ratio Trapping
Authors: Li Jizhong , Bai J. , Major C. , Carroll M. , Lochtefeld A. , Shellenbarger Z. 
Published: April 2011

AbstractWe report on the MOCVD growth of GaAs on patterned Si utilizing the Aspect Ratio Trapping (ART) method to reduce threading dislocations resulting from lattice mismatch. Defect-free GaAs was obtained from growth in sub-micron trenches formed in SiO2 on Si (001) substrates. Material quality has been characterized by cross-sectional and plan-view TEM and XRD. It was found that when growing GaAs above the trenched region, coalescence-induced threading dislocations (TDs) and planar defects were introduced at the coalescence junction interfaces. These defects were found to be unrelated to the misfit defects (MDs) on GaAs/Si interface that originated during initial epitaxial growth. Causes of coalescence defect formation were experimentally investigated by employing a two-step defect reduction scheme. It is concluded that by further optimizing growth conditions during coalesce layer growth, low defect-density GaAs material can be obtained on Si substrate.
Advances in the Research of the Intermediate Band (IB) Solar Cell
Authors: Luque Antonio , Martí Antonio 
Published: April 2011

AbstractWe describe the present state of the intermediate band (IB) solar cell research, a cell concept with very high efficiency potential. A comprehensive presentation of the theory is included followed of a description of its implementation using quantum dots and of the experiments performed to prove their principles. Present solar cells do not give today very high efficiencies; the steps to be given towards the real achievement of higher efficiencies is described and the use of alloys, instead of nanostructured materials, to fabricate IB cells is also discussed.
Evidence of Sequential Carrier Escape in III-V p-i-n Multi-Quantum Well Solar Cells
Authors: Alemu Andenet , Coaquira Jose A. H. , Freundlich Alex 
Published: April 2011

AbstractSeveral InAsP/InP p-i-n Multi-Quantum Well (MQW) solar cells, only differing by their MQW region composition and geometry, were investigated. For each sample, the Arrhenius plot of the temperature related variation of the photoluminescence intensity was used to deduce the radiative recombination activation energy. The electron and holes confinement energy levels in the quantum wells and the associated effective potential barriers seen by each carrier were theoretically calculated. Carrier escape times were also estimated for each carrier. The fastest escaping carrier is found to display an effective potential energy barrier equal to the experimentally determined photoluminescence activation energy. This not only shows that the temperature related radiative recombination extinction process is driven by the carrier escape mechanism but also that the carriers escape process is sequential. Moreover, a discrepancy in device performance is directly correlated to the nature of the fastest escaping carrier.
Fabrication of Discrete Track Media with Patterned Servo-areas and Tracks on Disk Substrate
Authors: Tsuchiya Yuko , Ito Kenichi , Haginoya Chiseki , Hirayama Yoshiyuki 
Published: April 2011

AbstractDiscrete track media (DTM) with patterned servo-areas and recording tracks were fabricated on disk substrates in a two-step RIE process, creating a fine pattern transfer from an imprinted resist mask to a substrate surface without variations in groove depth. The fabricated DTM with perpendicular magnetic recording layers flew stably during read out signal detection.
Compositional Evolution of FePt Nanoparticles Prepared by Different Organometallic Synthesis Routes
Authors: Srivastava Chandan , Thompson Gregory B 
Published: April 2011

AbstractSelf-assembled FePt nanoparticle arrays are candidate structures for ultrahigh density magnetic storage media. One of the factors limiting their application to this technology is particle-to-particle compositional variation. In the present study, an analysis is provided for the formation mechanism of FePt nanoparticles synthesized from the thermal decomposition of Fe(CO)5 and the reduction of FeCl2 by superhydride. In both processes, Pt rich seeds initially form from the reduction of Pt acetylacetonate. The particle formation mechanism has been studied by extracting particles at different stages of the synthesis and individually determining particle-to-particle composition by STEM-XEDS. In the case Fe(CO)5, the Fe is gradually incorporated into the Pt seeds and produces a wide variation in compositional distribution about the mean value. In contrast, the FeCl2 has a nearly instantaneous shift in composition to the average value with the introduction of the superhydride reducing agent. The discrepancies in compositional uniformity between the two processes will be discussed in terms of the intrinsic differences between the different precursors.
The Effect of Fe Substitutions on the Microstructure of Gd5Si2Ge2
Authors: Podmiljsak Benjamin , McGuiness Paul , Kobe Spomenka , Skulj Irena 
Published: April 2011

AbstractGd5Si2Ge2 exhibits the so-called giant magnetocaloric effect, making it a potential material for next-generation near-room-temperature permanent-magnet-based refrigeration devices. In the as-cast form this material is relatively complicated in terms of its structure and its metallurgy.Recent reports have suggested that small additions of iron can substantially improve the problems associated with hysteresis losses, so enhancing the material's potential for real-world applications. We have looked at iron substitutions in the range X=0 to X=1 for Gd5Si2-XGe2 to investigate the macrostructures and microstructures of cast and homogenized materials, with particular emphasis on the amount of iron substituting for silicon in the Gd5(SiGe)4 phase and the effect of the substituting iron on the Ge/Si ratio. The larger iron substitutions were found to eliminate the unusual macrostructures, and conventional ingots with smooth surfaces were the result. The iron was also found to dissolve at levels of 1-3% in the Gd5(SiGe)4 phase and encourage the formation of the Gd5(SiGe)3 phase at the expense of the magnetocaloric Gd5(SiGe)4 phase. A substitution of X=1 was found to be sufficient to produce as-cast microstructures consisting almost entirely of the Gd5(SiGe)3 phase.With a scanning electron microscope (Jeol 840A) and an analytical transmission electron microscope (Jeol 2010 F with a field-emission gun) and an EDXS system from Oxford Instruments (Link Isis 300) we performed a detailed microstructural investigation of the processed materials. Special emphasis was placed on the intergrain regions and an assessment of the amount of Fe substituting in the main magnetocaloric phase.
Epitaxial Growth of Fe3Si Thin Films on (100) Magnesia Substrates
Authors: Akiyama Kensuke , Kaneko Satoru , Kadowaki Teiko , Hirabayashi Yasuo , Kyoduka Azusa , Sawada Yutaka , Kobayashi Yoshihiko , Asai Kichizo , Funakubo Hiroshi 
Published: April 2011

AbstractA high-quality (100)-oriented epitaxial Fe3Si films were grown on (100) MgO substrates by RF-magnetron sputtering. The full width at half maximum of the Fe3Si 400 rocking curve was 0.18°, when the film was grown at 750°C. The epitaxial films of 100 nm thicknesses had a smooth continuous surface. The coercive field (Hc) was approximately 10 Oe, and the saturation magnetization (Ms) was 900 emu/cm3, which are almost the same as those of bulk Fe3Si. The anisotropy constant (K1) of magnetization indicated that the epitaxial Fe3Si films grown at 750°C mainly consisted of long range ordering phase (DO3 phase) and that the epitaxial films post-annealed at 900°C was constituted with ordering phase.
Large Magnetoresistance Variation of Pseudo Spin Valves with Different Nano Oxide Layer Position
Authors: Suh Jeong Dae , Ross C.A. 
Published: April 2011

AbstractWe have investigated the influence of the nano-oxide layer positions on giant magnetoresistance(GMR) of the NiFe(9nm)/Cu(4nm)/Co(5nm) pseudo spin valves. Nano-oxide layer positions had a several effects on the multilayer structure that changes its magnetotransport behavior. GMR ratio varied between 2.8% and 0.15% depending on the nano-oxide layer positions within the stack. The increase of the GMR ratio was accompanied by increase in resistance change, decrease in sheet resistance, and decrease in surface roughness. These significant variations of GMR ratio was explained by the changes on the spin dependent scattering or current shunting effect. Our results showed that appropriate placement of a nano-oxide layer was essential fo optimize magnetoresistance and properties of spin valves.
Magnetoresistance in Spin Valves Based on Organic Semiconductors with Ferromagnetic Electrodes
Authors: Tada Hirokazu , Kakita Motoyasu , Ikegami Tomonori , Nagano Tomohiro , Kawayama Iwao , Tonouchi Masayoshi 
Published: April 2011

AbstractWe have prepared layered sandwich structures composed of Co / organic materials / La0.67Sr0.33MnO3 and measured the magnetic field effect on electrical resistance. We inserted various OMs including pentacene, C60, 8-hydroxy-quinoline aluminum and titanyl-phthalocyanine with a thickness in the range from 200 nm to 1,000 nm. All devises prepared showed clear spin-valve characteristics with magneto-resistance (MR) ratios of approximately a few to 10% at low temperature. It was found that spins were transported in rather thick organic films, and the polarity of MR depended upon materials inserted and their film thickness.
Characterization of Epitaxial Bi-Layer-Structured Bi5Ti3FeO15 (m = 4) and Bi4Ti3O12-Bi5Ti3FeO15 (m = 3-4) Natural-Superlattice-Structured Multiferroic Thin Films Prepared by Pulsed Laser deposition
Authors: Nakashima Seiji , Nakamura Yoshitaka , Okuyama Masanori 
Published: April 2011

AbstractBi-layer-structured mutiferroic Bi5Ti3FeO15 (BTFO15) (m = 4) and natural-superlattice-structured Bi4Ti3O12- Bi5Ti3FeO15 (BIT-BTFO15) (m = 3-4) thin films have been prepared on (001) and (110) oriented SrTiO3 (STO) single crystal substrates by using pulsed laser deposition. X-ray diffraction patterns of these thin films on (00l) STO single crystals shows the obtained thin films were (00l)-oriented layer-perovskite single phase, and BIT-BTFO15 (m = 3-4) natural-superlattice-structure has also obtained. On (110) STO single crystal, layer perovskite (11l) oriented thin films have been also obtained. For characterizing ferroelectric properties, these thin films have been prepared on (001) and (110) oriented La-doped (3.73 wt%) STO single crystal substrates. From ferroelectric D-E hysteresis loops measurements, BTFO15 (m = 4) and BIT-BTFO (m = 3-4) thin films on (110) La-doped STO single crystals shows good ferroelectric hysteresis loops and their double remanent polarizations (2Pr) were 47 μC/cm2 and 44 μC/cm2, respectively. However, these thin films on (001) La-doped STO single crystals do not show ferroelectric characteristics.
Multiferroic Bi2NiMnO6 with a Double-Perovskite Structure: High-Pressure Synthesized Bulk and Epitaxially Grown Thin Films
Authors: Shimakawa Yuichi 
Published: April 2011

AbstractA new multiferroic compound Bi2NiMnO6 was synthesized in both bulk and thin-film forms. Bulk samples were prepared under a high pressure condition at 6 GPa, and thin-film samples were epitaxially grown on single-crystal SrTiO3 substrates by a pulsed-laser deposition method. The crystal structure of the material is a double perovskite, in which Ni2+ and Mn4+ ions are ordered in a rock-salt configuration. Bi3+ ions at the A-site cause a noncentrosymmetric (C2) structural distortion which allows a spontaneous ferroelectric polarization at room temperature. Ni2+–O–Mn4+ magnetic paths lead to ferromagnetism through the superexchange interaction according to the Kanamori-Goodenough rule. A coupling between the ferromagnetic and ferroelectric interactions appears to exist, but it is quite small.
Dynamical Nonlinearities in Piezoelectric Materials
Authors: Seppälä Eira , Korpelainen Virpi , Ojasalo Kari , Sarjala Matti , Alava Mikko , Lassila Antti , Manninen Antti 
Published: April 2011

AbstractDynamical nonlinearities in piezoelectric materials have been investigated over different time and frequency scales using four different methods; measurements of displacement and electric polarization of bulk material, measurements of nanometer scale surface structure of the material by an atomic force microscope (AFM), and numerical modelling of ferroelectric materials with quenched randomness. Laser vibrometer measurements of the deformations of piezoelectric materials, d31 type PZT and PMN-PT sheets, have been done under sinusoidal voltage loading with different frequencies. This yields information about the dynamical hysteresis behavior, such as the area of the hysteresis loops as a function of the applied frequency f and voltage amplitude. Similarly the hysteresis loops have been measured for the electric polarization of the same samples. Relaxation behaviors of the same materials have been measured by an AFM. Topography of the piezo sheets was measured after applied DC voltage, indicating slow collective changes in the polarization close and at the sample surface. To investigate the time-dependent hysteresis, we have studied numerically a Ginzburg-Landau-Devonshire (GLD) model for ferroelectric materials including dilution type quenched randomness. Quantities studied include the area of the hysteresis loop, of the polarization in the material, and the coercive electric field Ec as a function of the frequency f, both as a function of the disorder strength.