bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Fabrication and Thermoelectric Properties of Amorphous Si-Ge-Au Bulk Samples
Authors: Lee Sang Min , Okamoto Yoichi , Kawahara Oshio , Morimoto Jun 
Published: April 2011

ABSTRACTThe amorphous Si-Ge-Au bulk samples were fabricated with using the melt spinning method for the practical power supply or cooling devices. X-ray diffraction results showed that our samples were amorphous and the thermoelectric properties were measured by DC method. Although the electrical resistivity of the bulk sample was higher than that of the amorphous thin film, the thermoelectric power of the bulk sample was larger. The thermal conductivity of the amorphous Si-Ge-Au bulk sample was almost the same to the conventional crystalline Si-Ge bulk value. Consequently, non-dimensional figure of merit ZT is around 2 (at 600 K, • •=6.5 10λ-1V/K, • =1.9 10 ohm-m, • •= 6 W/mK) that is about ten times higher than the conventional crystalline Si-Ge bulk value.
Instrumented-Indentation for Mechanical Characterization of Boron Carbide Nano-Composite Coatings
Authors: Walter Mark , Nekkanty Srikant , Cooke Elizabeth , Doll Gary 
Published: April 2011

AbstractBoron carbide (BC) is well known as a coating material that is important for a wide range of technological applications. The applicability of boron carbide stems from the fact that it is a very hard material with high lubricity, high elastic modulus, low specific gravity, and good chemical stability. Disadvantages, however, include extreme brittleness and sometimes poor adhesion. Recently, a reactive sputtering involving boron carbide targets and hydrocarbon gases has been used to produce novel nano-composite boron carbide thin films comprised of BC nano-crystals embedded in a matrix of hydrogenated amorphous carbon (DLC). The microstructure of these thin films is similar to that of other metal carbide/DLC nano-composite films. The present paper discusses the results of Vickers indentation experiments carried out on four different samples of boron carbide/DLC coatings that were sputtered deposited onto 52100 steel disks. The four different samples resulted from four different levels of hydrocarbon gas flow during processing. Acoustic emission data was recorded simultaneously with the indentation experiments. The indentations and the associated crack patterns were observed using scanning electron microscopy.
Nanoindentaion and Wear Behavior of Nickel-Titanium Alloys and Thin Films
Authors: Ni Wangyang , Grummon David S. 
Published: April 2011

AbstractThe unusual constitutive behavior of NiTi alloys that display shape memory and transformational superelasticity may impart useful tribological properties. This paper presents some preliminary results on nanoindentation and pin-on-disk wear experiments that suggest potential tri-bological applications of NiTi alloys. It is shown that high levels of spring-back reversibility together with high hardness, as measured by nanoindentation experiments, correlate with improved wear resistance in bulk Nitinol alloys. Amorphous thin films of equiatomic NiTi, which are readily produced by physical vapor deposition, were found to be especially hard and wear resistant. Finally, stress induced B2-B19' transformation is shown to occur during wear-loading of martensitic NiTi, indicating that wear processes are capable of inducing superelastic effects in B2 NiTi alloys.
Effect of Tribological Properties of Undoped and Florine-Doped Silicon Di-Oxide Fims on Chemical Mechanical Planarization Process
Authors: Sikder A.K. , Thagella S. , Bandugilla U.C. , Kumar Ashok 
Published: April 2011

AbstractChemical mechanical planarization (CMP) occurs at an atomic level at the slurry/wafer interface and hence slurries and the interaction of the films and polishing pads play a critical role in the successful implementation of this process. Understanding the tribological properties of a dielectric layer in the CMP process is critical for successful evaluation and implementation of the materials. In this paper, we present the effect of tribological properties of undoped and florine doped silicon dioxide films on their CMP process. A micro-CMP tester was used to study the fundamental aspects of CMP process. We have studied the CMP process of oxides on polyurethane pads (IC1000-B4/SubaIV) with colloidal silica slurry at different conditions. The coefficient of friction (COF) and acoustic emission signal was monitored during process. The COF was measured during the process and was found to varies differently for different samples and with down force and platen roatation. The effects of machine's parameters on the polishing performance and correlation of physical phenomena with the process has been discussed.
All CO2-Processed Fluoropolymer-Containing Photoresist Systems
Authors: Flowers Devin , Hoggan Erik , DeSimone Joseph M. , Carbonell Ruben 
Published: April 2011

AbstractCurrently, the microlithography industry creates large amounts of organic and aqueous wastes in the production of semiconductors. Using carbon dioxide can possibly eliminate the majority of these waste solvents as well as eliminate the image collapse problems shown with aqueous base development. We will discuss the use of carbon dioxide to replace the most solvent intensive steps of the microlithography process, spin coating, developing, and stripping. However, before CO2 can replace conventional solvents, photoresist systems must be designed and synthesized to be compatible with CO2. These photoresist systems must be soluble in liquid CO2 to insure that thin-uniform coatings can be produced by spin coating while maintaining characteristics of conventional resist systems such as low absorbance, high sensitivity, solubility contrast, good resolution, and etch resistance. Using our CO2compatible resist system, we will demonstrate the ability of CO2 to spin coat uniform thin-films which (after exposing and PEB) can be developed using scCO2 to produce lithography features that may be stripped in CO2. Thus, revealing the enormous potential of CO2 to provide the microlithography industry an opportunity to escape its water and organic solvent dependence as it moves toward 157nm lithography.
EUV Lithography: Patterning to the End of the Road
Authors: Cobb Jonathan L. , Brainard Robert L. , O'Connell Donna J. , Dentinger Paul M. 
Published: April 2011

AbstractExtreme Ultraviolet (EUV) lithography is gaining momentum as the patterning technology of choice for the semiconductor nodes with less than 70-nm half-pitch. As such, it must be ready for manufacturing in the 2006-2007 time frame, and it must be extendable to the lower limits of CMOS technology. Successful patterning of 40-nm dense lines in viable EUV photoresists indicates that today's resist materials may have the necessary resolution, but better optics are needed to verify this more rigorously. Although little is understood about the impact of line-edge roughness (LER) on device performance, it is generally assumed that EUV LER must be less than 3 nm 3σ. EUV lines have been printed with LER as low as 4 nm 3σ, but they were printed with unacceptable photospeed. Deliberate attempts to increase the photospeed while maintaining low LER have produced a resist with sizing dose of 1.7 mJ/cm2 and LER of 6.6 nm 3σ. Photospeed is important because EUV photons are difficult to create, and the photoresist must use them efficiently for economically acceptable throughput. Throughput models indicate that patterning doses may need to be 1-2 mJ/cm2, and only 30-40% of these photons will be absorbed, so the resists must be able to accommodate statistical dose fluctuations that are an appreciable fraction of the mean dose. Highly sensitive resists such as these have been produced with good LER. Since all resist materials absorb EUV radiation strongly, the photoresist layer will have to be less than 150 nm thick. Resists this thin pose problems for device manufacturing, largely because they will not have acceptable etch resistance, and this etch resistance will have to be recovered in some other way. Efforts have begun to integrate hard masks with thin resists in real device fabrication. Defect data indicate that defect densities do not increase in resist films less than 100 nm thick, and transistors, via chains, and microprocessors have all been fabricated with these thin-resist/hard-mask integrations.
Resistless Patterning of Magnetic Storage Media Using Ion Projection Structuring
Authors: Dietzel A. , Berger R. , Grimm H. , Schug C. , Bruenger W. H. , Dzionk C. , Letzkus F. , Springer R. , Anders S. , Bandic Z.Z. , Rettner C.T. , Terris B.D. , Eichhorn H. , Boehm M. , Adam D. , Loeschner H. , Platzgummer E. , Stengl G. 
Published: April 2011

AbstractCo/Pt thin film multilayers with strong perpendicular anisotropy and out-of-plane coercivities of 5-11 kOe were magnetically altered in areas of local ion beam interaction. The ion irradiations were performed by ion projection through silicon stencil masks fabricated by silicon on insulator (SOI) membrane technology. The ion projector at the Fraunhofer Institute for Silicon Technology (ISiT) was operated at 73 keV ion energy and with a 8.7- fold demagnification. After exposure to 3 × 1014Ar+/ cm2 magnetic islands smaller than 100 nm in diameter were resolved in the Co/Pt multilayersby means of magnetic force microscopy. The impact of different ion species (He+, Ar+ and Xe+) and ion energies (10 – 200 keV) on the multilayer structure was evaluated using Monte Carlo simulations. The ballistic interface intermixing was used to predict magnetic coercivity changes for various irradiation conditions. The simulations revealed that with 73 keV Ar+ and Xe+ ions the irradiation dose could be reduced by a factor of 100 and 400 respectively in comparison to 73 keV He+which was verified in the experiments. X-ray reflectivity measurements confirmed that the Co/Pt superlattice structure is slightly weakened during the irradiation and that the surface smoothness of the media is preserved. Using the Ion Projection Process Development Tool (PDT) at IMS-Vienna concentric data tracks including head positioning servo informations were patterned onto a 1” IBM microdrive™ glass disk which was coated with Co/Pt multilayers. In a single exposure step several tracks within an exposure field of 17 mm in diameter were structured by 2 × 1015He+/ cm2 at 45 keV using a 4- fold demagnification set-up.
Nanoscale Pattern Transfer Using Sputter-Induced Corrugations Formed at the Si/SiO2 Interface
Authors: Allen Cary G. , Daniels Matthew , Umbach Christopher C. , Blakely Jack M. 
Published: April 2011

AbstractA conventional ion mill used for thinning transmission electron microscope samples has been used to produce nanoscale surface corrugations on the thermal oxide of Si. Using Ar ions with energies from 1.1 to 2.5 keV in an off-normal incidence geometry, the corrugations were produced with wavelengths from 30 to 80 nm and amplitudes of ~1 to 2 nm. The corrugated pattern in the oxide has been transferred to the underlying Si substrate by reactive ion etching, producing structures that have a much higher aspect ratio than the original corrugations.
Large Scale Periodic Magnetic Nanostructures Fabricated by Optical Interference Lithography
Authors: Carl A. , Kirsch S. , Wassermann E.F. 
Published: April 2011

AbstractLarge scale periodic arrays of Co/Pt multilayer dots with perpendicular magnetic anisotropy are fabricated utilizing optical interference lithography with Ar+ ion lasers operating at wavelengths of 457nm and 244nm, respectively. The experimental technique allows us to fabricate dot-arrays with periodicities ranging between 125nm and 1100nm and with corresponding dot diameters between 70nm and 740nm. The dot-arrays are prepared on (100)-silicon substrates covering a total area of up to 20cm2 with a maximum dot density of about 4.1x1010dots/in2 as well as within the surface of (110)-silicon substrates. The global magnetic properties of the dot-arrays are characterized by the magneto-optical Kerr effect. The micromagnetic properties of a single Co/Pt dot are measured with quantitative magnetic force microscopy (QMFM) by using a MFM-tip, the magnetic properties of which have been calibrated within the point probe approximation with nanofabricated current carrying rings. This allows us to measure quantitatively the z-component of both the magnetization and the stray field of a Co/Pt dot on the nanometer scale.
Dual-Mode Optical Molecular Switching Systems for Organic Memories
Authors: Galvão D.S. , Braga S.F. , Barone P.M.V.B. , Dantas S.O. 
Published: April 2011

ABSTRACTThe synthesis of dual-mode optical molecular switching systems has been recently achieved. These systems were based on chiral helical-shaped alkenes in which the chirality can be reversibly modulated by light. In this work we report a theoretical study on the geometric and spectroscopic properties of these structures using the well-known semi-empirical methods PM3 (Parametric Method 3) and ZINDO/S-CI (Zerner's Intermediate Neglect of Differential Overlap -Spectroscopic - Configuration Interaction). Our results show that there are two stable conformers very close in energy for each possible molecular helicity presenting a barrier of ∼40 kcal/mol for bond rotation along the main molecular axis. Under protonation these barriers increase significantly and might explain why the protonation leads to the blocking of the switching process. We propose a scheme for the switching mechanism based on charge transfer and conformational changes during the isomer interconversion.
Generation and Transport of Photocarriers in Head-Tail Poly(3-Alkylthiophene) Films
Authors: Rikitake Koichi , Takashima Wataru , Kaneto Keiichi 
Published: April 2011

ABSTRACTPhotovoltaic effects in Schottky Junction cells composed with Au/head-tail poly(3-hexylthiophene) (HT-P3HT)/Al have been studied as a function of excitation photon energy and temperature. It has been found that photocarriers are effectively generated at the interface of HT-P3HT/Al from the excitation spectra of photocurrents (photoaction spectra), which were obtained upon illumination to the Au or Al sides. The photoaction spectra also suggest that the photocarrier generation occurs at around 2.3 eV and 3.5 eV, which correspond to the peak of φ-φ* absorption and the photon energy with lower optical density region, respectively. The mechanisms of photocarrier generation are discussed taking the role of the Schottky junction into consideration.
Optical Spectroscopic Studies of a Soluble Fluorene-Based Conjugated Polymer: A Hydrostatic Pressure and Temperature Study
Authors: Guha S. , Rice J.D. , Martin C. M. , Graupner W. , Chandrasekhar M. , Chandrasekhar H.R. , Scherf U. 
Published: April 2011

ABSTRACTSpectroscopic properties of conjugated molecules/polymers have varying degrees of sensitivity to backbone conformation. Optical studies are presented as a function of temperature and hydrostatic pressure, using photoluminescence and Raman scattering from two polymers with distinct differences in their backbone conformation, namely, polyfluorene (PF) and ladder type poly(para-phenylene)(m-LPPP). In contrast to the photoluminescence (PL) vibronics in mLPPP, the 0-0 PL vibronic peak in PF shows a red-shift with increasing temperatures. Pressure studies reveal that the PL spectrum of PF red-shifts and broadens with increasing pressures. The phonon lines in PF show an antiresonance effect at higher pressures indicating a strong electron-phonon interaction.
Electrophosphorescent Light Emitting Devices Using New Iridium(III) Complexes
Authors: Das Rupasree Ragini , Lee Chang-Lyoul , Kim Jang-Joo 
Published: April 2011

ABSTRACTWe have synthesized a new tris-orthometalated Ir(mpp)3 and several bis-orthometalated Ir(III) complexes of 3-methyl-2-phenylpyridine(Hmpp). The influence of the methyl substituent in Hmpp and different ligand environments on the optical, electrochemical and electroluminescence properties of the orthometalated complexes are examined by varying the donor acceptor properties. This includes several uninegative bidentate ligands consisting of different organic functional groups. Absorption, excitation and emission spectra in solution and solid state of these complexes agree with a strong electronic excitation to 1MLCT in Ir(mpp)3 and preferably to 3MLCT in other complexes. These complexes demonstrate strong phosphorescence at room temperature with a lifetime of 1-2 μs. Multilayer organic light emitting devices using these complexes as the triplet emitter are studied using PVK (poly(9-vinyl carbazole)), CBP (4,4'-N,N'-dicarbazole-biphenyl) and TAZ (3-phenyl-4-(1'-napthyl)-5-phenyl-1,2,4-triazole) as the host materials. Ir(mpp)3exhibits quite different behavior in different host materials.
Design of Luminescent Polymers for Leds
Authors: Holmes A. B. , Bond A. D. , Davies J. E. , Fischmeister C. , Frey J. , Hennecke U. , Li J. , Ma Y. , Martin R. E. , Rees I. D. , Robinson K. , Sano T. , Cacialli F. , Lim S. F. , Friend R. H. 
Published: April 2011

ABSTRACTA 2,3-dibutoxy-1,4-phenylenevinylene comonomer was incorporated into a distyrylbenzene derivative 11. Novel 1,2-disubstituted-3,6-dibromobenzene comonomers 15 and 18 were prepared by directed metallation. Copolymerization of 11with a 9,9-dioctylfluorene-2,7-diboronate ester 1 yielded a green fluorescent polymer while copolymerization of 15 and 18 with the 9,9-dihexylfluorene-2,7-diboronate 22 afforded promising blue fluorescent polymers 23 and 24 respectively.
The Effects of Processing Conditions on the Efficiency and Lifetime of Organic Light Emitting Devices Incorporating a New Oxadiazole Derivative
Authors: Jung G.Y. , Wang C. , Cea P. , Pearson C. , Bryce M.R. , Petty M.C. 
Published: April 2011

ABSTRACTThe effects of processing conditions on the properties of organic light emitting devices (LEDs) based on rubrene-doped poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] and a new electron transporting material, 2,5-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]pyridine, are reported. These dual-layer LEDs exhibited a higher quantum efficiency than observed for structures incorporating the more widely used electron transport compound 1,3-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]benzene (OXD-7). However, the as-prepared devices degraded relatively rapidly on storage (10-1 mbar, no applied bias). Thermal annealing of the degraded devices at 160 °C for 30 minutes restored the currents and light outputs close to those measured for fresh devices. The annealed LEDs exhibited a significant increase in their operating lifetime. Lifetime improvements could also be achieved by increasing the deposition rate and thickness of the thermally evaporated aluminium top electrode. These effects are attributed to better adhesion between the aluminium top electrode and the underlying electron transport layer.
Organic Solar Cells Based on Evaporated Planar and Bulk Heterojunctions of a PPVpentamer and C60
Authors: Geens W. , Aernouts T. , Poortmans J. , Hadziioannou G. 
Published: April 2011

ABSTRACTThe technique of vacuum evaporation has been applied to deposit organic photovoltaic active layers. The five-ring PPV-type oligomer 2-methoxy-5-(2'-ethylhexyloxy)-1,4-bis((4',4”-bisstyryl)styrylbenzene) (MEH-OPV5) and C60 act as respectively donor and acceptor materials in planar heterojunction (MEH-OPV5/C60) and bulk heterojunction (MEH-OPV5:C60) devices. These devices were fabricated with ITO/PEDOT:PSS bottom electrodes and Al top contacts. The performance of both solar cell configurations has been compared. It was found that under AM1.5 illumination the MEH-OPV5/C60 cells exhibit a higher open-circuit voltage (∼ 1.00 V) than the MEH-OPV5:C60 devices (∼ 0.92 V). On the other hand, the limited exciton diffusion length in these materials was reflected in the lower short-circuit current density of the planar heterojunction cells as compared to the bulk heterojunction structures. Overall AM1.5 power conversion efficiencies reaching 2 % are reported. Also the influence of the organic layer thickness and the substrate temperature during deposition on the device performance has been addressed. Thick organic films generally induce a high series resistance that limits both the short-circuit current density and the fill factor. An elevated substrate temperature during deposition of the MEH-OPV5:C60 layers onto ITO/PEDOT:PSS led to the formation of nucleated islands of 100 - 150 nm diameter with holes in between. As a result, no reliable photovoltaic devices could be realized with such organic films. AFM analysis and spectral response measurements supported these findings.
Corrosion Performance Projection of Yucca Mountain Waste Packages
Authors: Sagüés Alberto A. 
Published: April 2011

ABSTRACTThe proposed high-level nuclear waste repository at Yucca Mountain relies heavily on the corrosion resistance of waste packages (WP) emplaced in tunnels bored through tuffaceous rock for adequate performance during the anticipated 10,000 years regulatory period. Present WP design uses a ∼20-mm-thick outer shell of Alloy 22 as the main corrosion-resistant barrier. The operating conditions may include an initial high-temperature (>96 °C) pulse that will last approximately several hundred to a thousand years. Ti-alloy shields are envisioned to prevent water from directly dripping on the WP. However, recent findings suggest that deliquescent salts and other contaminants on the WP surfaces may cause liquid water to form there, even at high temperatures. Current performance projections predict that during the anticipated regulatory period localized corrosion modes will be unlikely and that the Alloy 22 barrier will degrade primarily by very slow uniform dissolution, essentially under passive surface conditions. A review is presented of the assumptions and experimental findings leading to those projections, as well as a discussion of findings of a recent Workshop on the challenges involved in extrapolating limited information on corrosion behavior over an extremely long service period that extends beyond the time frame of common engineering experience. Potential mechanisms for deterioration of the passive regime that may be encountered under those circumstances are discussed.
Synthesis and Examination of New Actinide Pyrochlores
Authors: Laverov N.P. , Yudintsev S.V. , Stefanovsky S.V. , Jang Y.N. , Ewing R.C. 
Published: April 2011

ABSTRACTPyrochlore is a complex oxide with general formula VIIIA2VIB2O6X (X – additional anion in specific position, usually O2-). It has a fluorite-derived structure (space group Fd3m) where one-eighth of oxygens are missing. Two different structural sites for cations exist, resulting in the cell parameter of pyrochlore is twice that of the fluorite lattice. Some pyrochlore-based actinide waste forms have been produced in the systems: CaO-CeO2-TiO2, CaO-UO2(ThO2)-ZrO2, CaO-UO2(ThO2)-Gd2O3-TiO2-ZrO2, and CaO-ThO2-SnO2. The oxide precursors were cold pressed at 200 – 400 MPa and sintered at 1500 – 1550 °C for 6-10 hours in air or at 1300 – 1350 °C for 5-50 hours in pure oxygen (Ce-doped batches only). The use of pure oxygen was used to try to put Ce in the tetravalent state required to form a pyrochlore.The products were examined with XRD, SEM/EDS, and TEM. In the ceramics with bulk compositions: CaCeTi2O7, CaThZr2O7, (Ca0.5GdTh0.5)(TiZr)O7, (Ca0.5GdU0.5)(TiZr)O7, and CaThSn2O7, pyrochlore was the major phase, but fluorite-structured oxide was also present. In the samples with target compositions CaUZr2O7 and (Ca0.5GdU0.5)Zr2O7 pyrochlore was not identified, rather a fluorite-structured oxide appeared. Different occurrences of pyrochlore and defect fluorite in the ceramics produced are due to crystal chemical constraints.