bluuebunny/crossref_metadata_2025_split huggingface dataset:
GaN Photonic Crystal-Based, Enhanced Fluorescence Biomolecule Detection System
Authors: Dawson J. M. , Nightingale J. R. , Tompkins R. P. , Cao X. , Myers T. H. , Hornak L. A. , Korakakis D. 
Published: April 2011

AbstractThe need for small form factor, portable biosensing platforms is prevalent across a wide range of medical, environmental, and defense applications. This paper presents the design of a novel, integrated optofluidic photonic crystal biosensor architecture that shows potential for meeting the single molecule detection requirements of these application areas. GaN is being targeted as the photonic crystal slab material due to its transparency in the visible spectral range and also the potential for creating high aspect ratio photonic crystal lattices via polarity inverted MBE growth. Results of optical modeling efforts indicating 10-15x resonant enhancement of fluorescent emission and polarity inversion GaN growth techniques will be discussed.
TRANSMISSION ELECTRON MICROSCOPY STUDY OF INTERFACE REGION OF ALN / 6H-SIC
Authors: Chaudhuri Jharna , Nyakiti Luke Owuor , Lu Peng , Edgar James H , Li Peng 
Published: April 2011

AbstractTransmission electron microscopy (TEM) study was performed to investigate the interface region of AlN/6H-SiC. Thick AlN layers were grown on a 3.5° off-axis 6H-SiC substrate at a temperature of 1790 °C for 100 hours by sublimation-recondensation method. The energy dispersive x-ray spectroscopy (EDXS) analysis indicated considerable amount of aluminum and nitrogen present in the substrate and Si and C present in AlN. Lattice images of cross-sectional TEM samples show a faceted interface with step growth.
Controlling Swelling of Portland Brownstone
Authors: Wangler Timothy , Scherer George W. 
Published: April 2011

AbstractMany clay-bearing sedimentary stones such as Portland Brownstone will swell when exposed to water, and this can generate damaging stresses as differential strains evolve during a wetting cycle. Current swelling inhibitors, consisting of α,ω-diaminoalkanes, can reduce swelling in Portland Brownstone up to 50%. In this study, through X-ray diffraction and swelling strain experiments, we demonstrate that the α,ω-diaminoalkanes inhibit swelling by substituting for interlayer cations and partially hydrophobicizing the interlayer, then rehydrating on subsequent wetting cycles. We also introduce the copper (II) ethylenediamine complex as a potential treatment for swelling inhibition.
The Grolier Codex: A Non Destructive Study of a Possible Maya Document using Imaging and Ion Beam Techniques
Authors: Ruvalcaba Jose Luis , Zetina Sandra , Calvo del Castillo Helena , Arroyo Elsa , Hernández Eumelia , Van der Meeren Marie , Sotelo Laura 
Published: April 2011

AbstractThe Grolier Codex has been a controversial document ever since its late discovery in 1965. Because of its rare iconographical content and its unknown origin, specialists are not keen to assure its authenticity that would set it amongst the other tree known Maya codes in the world (Dresden, Paris Codex and Madrid Codex).The document that has been kept in the Museo Nacional de Antropología in Mexico City, after its exposure in 1971 at the Grolier Club of New York, has been analyzed by a set of non-destructive techniques in order to characterize its materials including paper fibers, preparation layer and colors composition. The methodology included UV imaging, IR reflectography and optic microscopy examinations as well as Particle Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectrometry (RBS) using an external beam setup for elemental analysis. All the measurements were carried out at 3MV Pelletron Accelerator of the Instituto de Física, UNAM. The aim of this work is to verify if the materials in the Grolier Codex match those found for other pre-Hispanic documents.From the elemental composition we concluded that the preparation layer shows the presence of gypsum (CaSO4), color red is due to red hematite (Fe2O3) and black is a carbon-based ink. These results agree with previous analyses carried out by Scanning Electron Microscopy (SEM-EDX) on few samples. However, the presence of Maya Blue in the blue pigment cannot be assured. The examination using UV and IR lights shows homogeneity in the inks and red color but dark areas that contain higher amounts of K in the preparation layer. This paper discusses the results obtained for the UV-IR examinations and the elemental analysis. A comparison with other studies on pre-Hispanic and early colonial codex is presented.
Replication of Glazed Quartzite from Kerma, Capital of Ancient Kush (Sudan)
Authors: Ellis Lisa , Newman Richard , Barsanti Michael 
Published: April 2011

AbstractGlazes found on ancient Nubian quartzite sculpture were characterized in a previous study by scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM/EDS). Now in the collection of the Museum of Fine Arts, Boston, these objects were excavated in the early 20th century by the joint Harvard University-Boston Museum of Fine Arts Expedition, in ancient Kerma, the capital of ancient Kush. The project presented here attempts to recreate the ancient technology used to glaze quartzite with compositions determined in the previous study. Raw and fritted experimental glazes were prepared, as well as an alkali paste mixed with a copper colorant. All of the samples were fired in modern kilns. After firing, samples of the glazes and their quartzite substrates were examined with SEM/EDS.
Formation of III-V Semiconductor Engineered Substrates Using Smart CutTM Layer Transfer Technology
Authors: Letertre Fabrice Jerome 
Published: April 2011

ABSTRACTEngineered substrates are expected to play a dominant role in the field of modern nano-electronic and optoelectronic technologies. For example, engineered substrates like SOI (Silicon On Insulator) make possible efficient optimization of transistors' current drive while minimizing the leakage and reducing parasitic elements, thus enhancing the overall IC performance in terms of speed or power consumption. Other generations of engineered substrates like strained SOI (sSOI) provide solutions to traditional scaling for 32 nm node and beyond [1] technologies.The Smart Cutä technology, introduced in the mid 1990's by M. Bruel [2] is a revolutionnary and powerful thin film technology for bringing to industrial maturity engineered substrate solutions. It is a combination of wafer bonding and layer transfer via the use of ion implantation. It allows multiple high quality transfers of thin layers, from a single crystal donor wafer onto another substrate of a different nature, allowing the integration of dissimilar materials. As a consequence, it opens the path to the formation of III-V based engineered substrates by integrating, for example, materials like GaAs [3], InP [4], SiC [5], GaN [6], Germanium [7] ,and Si [8 ]on a silicon, poly SiC, sapphire, ceramic, or metal substrates?In this paper, we will review the current wafer bonding and layer transfer technologies with a special emphasis on the Smart Cut technology applied to compound semiconductors. Beyond SOI, the innovation provided by substrate engineering will be illustrated by the case of Silicon and SiC engineered substrate serving as a platform for GaN and related alloys processing [9,10,11,12] as well as the case of Germanium/Si platform for the growth of GaAs/InP materials, opening the path to Si CMOS and III-V microelectronics/ optoelectronics functions hybrid integration [13, 14]. Recent results obtained in these two focused areas will be presented to emphasize the added functionalities offered by engineered substrates.[1] B. Ghyselen et al., ICSI3 proc., 173 5 (2003)[2] M. Bruel et al., Electron. Lett., vol 31, p. 1201 (1995)[3] E. Jalaguier et al., Electron. Lett., 34(4), 408 (1998)[4] E. Jalaguier et al. Proc. llth Intern. Conf. on InP and Related Materials, Davos, Switzerland, (1999)[5] L. Di Cioccio et al., Mat. Sci. and Eng. B Vol. 46, p. 349 (1997)[6] A. Tauzin and al., Semiconductor Wafer Bonding VIII, ECS Proc Vol. 2005-02, pp. 119-127[7] F. Letertre, et al. MRS Symp. Proc., 809, B4.4 (2004).[8] B. Faure et al., Semiconductor Wafer Bonding VIII, ECS Proc Vol. 2005-02, pp. 106-118[9] H. Larèche et al., Mat. Sci. For., Vols. 457–460 pp.. 1621 – 1624 (2004)[10] G. Meneghesso et al , IEDM 2007, to be published[11] Y. Dikme et al., Journal of Crystal Growth, v.272 (1-4), pp. 500-505 (2004)[12] J. Dorsaz and al., Proceedings, ICNS6 (2005)[13] S.G. Thomas et al., IEEE EDL Vol. 26, July 2005.[14] K. Chilukuri, Semi. Sci. Technol. 22 (2007) 29-34
Effect of Si and Er Co-doping on Green Electroluminescence from GaN:Er ELDs
Authors: Wang Rui , Steckl Andrew J 
Published: April 2011

ABSTRACT(Er, Si) co-doped GaN thin films were grown on Si substrates by molecular beam epitaxy (MBE) technique. Electroluminescent devices (ELDs) were fabricated and the effect of Si co-doping on the performance of GaN devices was studied. Previous results with GaN:Er ELDs reported that electroluminescence (EL) was much stronger in reverse bias than in forward bias condition, indicating that the dominant factor in EL intensity was the electric field. The results reported here show the first time GaN:Er ELDs where forward bias EL is very much larger, indicating that the dominant factor is forward bias current. The electrical properties of (Si, Er) co-doped GaN thin films are believed to be responsible for the current control mechanism.
Fabrication and Electrical Studies of P(VDF/TrFE)(72/28) Copolymer based Non-Volatile Memory Devices as a Function of Varying Device Structures
Authors: Kim Kap Jin , Choi Chang Woo , Prabu Arun Anand , Yoon Sun 
Published: April 2011

AbstractFerroelectric characteristics of poly(vinylidiene fluoride/trifluoroethylene) (P(VDF/TrFE) (72/28 mol%)) copolymer ultrathin films used as an insulator in varying memory device architectures such as metal-ferroelectric polymer-metal (MFM), MF-insulator-semiconductor (MFIS), MIS and organic field-effect transistor (OFET) were studied using different electrical measurements. A maximum data writing speed of 1.69 MHz was calculated from the switching time measured using MFM architecture. Capacitance-voltage measured using MFIS was found to be more suitable for distinguishing the ‘0’ and ‘1’ state compared to MFM device structure. In OFET, the decreasing channel length increased the measured drain current (Id) values as well as its memory window enabling easier identification of the ‘0’ and ‘1’ state comparable to MFIS case. The data obtained from this study will be useful in the fabrication of non-volatile random access memory (NVRAM) devices with faster data R/W/E speed and memory retention capacity.
Reproducible Electro-resistance Memory Effect in Ag/La0.67Sr0.33MnO3 Thin Films
Authors: Huang Lina , Qu Bingjun , Liu Litian 
Published: April 2011

AbstractThe hysteretic and reproducible electro-resistance memory effect has been investigated in epitaxial La0.67Sr0.33MnO3 (LSMO) films under DC-bias stress and voltage pulses. The bias-sensitive current-voltage characteristic of the Ag/LSMO system is distinctly nonlinear, asymmetric and hysteretic, which indicates the appearance of the resistive switching. The diffusive resistance transition, which occurred during the field increase/decrease processes, is likely ascribed to a large intrasystem charge transfer for the electronic inhomogeneous heterostructure. The pulsed voltage amplitude and duration dependence of the nonvolatile resistive switch were also provided. Clear resistance switching cycles were observed at room temperature under voltage pulses of ±5V and ∼150ns. Reproducible switching properties, involving voltage-induced stepwise resistance change, resistance state saturation, and pulse duration dependent multilevel switchable capability, demonstrate well controllability with respect to future nonvolatile random access memory applications.
Optical and Morphological Characterization of PTCDI-C13
Authors: Stella Marco , Villar Fernando , Rojas Fredy Enrique , Della Pirriera Mónica , Voz Cristobal , Puigdollers Joaquim , Asensi José Miguel , Andreu Jordi , Bertomeu Joan 
Published: April 2011

AbstractThe organic photovoltaic technology has developed much in the last few years thanks to the optimization of the solar cell geometry and, specially, to the research for new performing materials. Nevertheless, much work has still to be done in order to better know the real mechanisms regulating the function of such novel class of semiconductors. The study of thin-film micro-structure, and the influence of the deposition parameters on it, is an important issue in order to obtain best optical and electrical properties. Thermal evaporation in high-vacuum chambers is the more suitable deposition technique to obtain organic thin-films with well organize molecular structure. Deposition parameters such as the substrate temperature and deposition rate may have some important effect on the molecules ordering. In this paper the effects of substrate temperature on structural and optical properties have been studied forN,N′-ditridecyl perylene diimide (PTCDI-C13) thin-films. Four samples have been deposited at 30, 60, 90 and 120°C substrate temperature and their absorption has been investigated by photothermal deflection spectroscopy (PDS) and transmittance spectroscopy. Moreover, simulations of the transmittance spectra have been calculated in order to obtain the optical constantsnandk. Finally atomic force microscopy (AFM) has been employed to analyze the superficial morphology of the thin-films.
Fabrication and Optical Properties of Electrospun Organic Semiconductor Nanofibers from Blended Polymer Solution
Authors: Chuangchote Surawut , Sagawa Takashi , Yoshikawa Susumu 
Published: April 2011

AbstractUltrafine organic semiconductor fibers with the average diameters ranging in sub-micro-down to nanometers (43 nm - 1.7 µm) were fabricated by electrospinning of a mixture of poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene-vinylene) (MEH-PPV) and polyvinylpyrrolidone (PVP) in various mixed solvents. The average diameter of the as-spun fibers decreased into nanometer scale with decreasing the concentration of PVP. Addition of a volatile organic salt (pyridinium formate, PF) or utilization of three-mixed solvent system was also effective to reduce the size of the diameter of as-spun fibers. After the removal of PVP from as-spun fibers by Soxhlet extraction, pure MEH-PPV fibers were obtained as a ribbon-like structure aligned with wrinkled surface in fiber direction. As-spun fibers showed relatively higher crystallinity, higher conjugation length, and a remarkable blue shift of photoluminescence (PL) peak was observed, in comparison with the cast film. The increase in composition of MEH-PPV and the removal of PVP from as-spun MEH-PPV/PVP fibers resulted in a significant blue-shift in UV-Vis absorption peak and red-shift in PL peak.
Fabrication of polycrystalline thin films of liquid crystalline materials by solution process and its application to OFETs
Authors: Iino Hiroaki , Hanna Jun-ichi 
Published: April 2011

AbstractWe have fabricated polycrystalline OFETs of two different liquid crystalline materials i.e., ω,ω'-dihexylquaterthipohene (6-QTP-6) and N, N'-ditridecylperylenediimide (13-Per-13) by solution process. Liquid crystalline materials help fabricating uniform thin films on the substrate when spin-coated at their temperature range of liquid crystalline phase. The FETs fabricated with 6-QTP-6 exhibited p-channel performance and its mobility was determined to be 0.04 cm2/Vs, which was comparable to that determined by time-of-flight experiments. The FETs fabricated with 13-Per-13 exhibited n-channel performance and its FET mobility was 0.008 cm2/Vs, while the mobility was increased up to 0.11 cm2/Vs after thermal annealing of the film at a liquid crystalline temperature of 220°C for an hour. Judging from these facts, the grain boundaries are controlled not so as to across the conduction channels formed by self-aligned π-conjugated aromatic cores in liquid crystalline molecules. We conclude that liquid crystalline material is a good candidate for quality polycrystalline thin films for OFETs.
Microstructural Characterization of Multi-Component Systems Produced by Mechanical Alloying
Authors: Pérez-Bustamante R. , Gómez-Esparza C.D. , Pérez-Bustamante F. , Estrada-Guel I. , Cabañas-Moreno J.G. , Herrera-Ramírez J.M. , Martínez-Sánchez R. 
Published: April 2011

ABSTRACTA series of binary to hexanary alloys (Ni, Co, Mo, Al, Fe, Cu) are produced by mechanical alloying. Formation of an FCC solid solution is observed in the binary system. For ternary to quinary systems the presence of an amorphous phase and a BCC solid solution is identified, and for the hexanary system a combination of BCC and FCC solid solutions is detected. There is a very small change in the lattice parameter of Mo, reflecting the limited solid solubility of other element in this structure. However, Mo induces the fast amorphization of other elements and the reduction of crystallite size.
Effect of Annealing on the Magnetic Properties of a Cold Rolled Non-Oriented Grain Electrical Steels
Authors: López G. N.M. , Salinas R. A. 
Published: April 2011

ABSTRACTThe effect of plastic deformation and subsequent annealing on the microstructure and magnetic properties (hysteresis core losses) of non-oriented grain semi-processed Si-Al electrical steel sheet are investigated. Plastic deformation of strip samples is performed by cold-rolling (5–20% reduction in thickness) along the original rolling direction. Annealing is carried out in air during 1 or 60 minutes at temperatures between 650 and 850°C. Measurements of B-H hysteresis curves are performed using a Vibrating Sample Magnetometer and characterization of annealed microstructures is carried out using optical metallography. The results show that hysteresis losses increase by a factor between 1.2 and 2.0 as the magnitude of the applied plastic deformation increases from 5 to 20% reduction in thickness. The rate of recovery of energy losses as a result of annealing depends on annealing time. Short annealing times produce full recovery of the effect of cold work and values of energy losses lower than in undeformed material. The magnitude of the additional recovery increases with strain but does not depend on annealing temperature. Long annealing times, which induce complete recrystallization, and either normal or abnormal grain growth, enhance recovery of hysteresis losses. The rate of recovery increases as both the strain and annealing temperature increase. Recovery of the deformation microstructure and internal stress relief produce only limited recovery of the magnetic properties. However, recrystallization and grain growth brings about a significant decrease in hysteresis losses.
In-Situ Observation of Oxide Monolayer Formation on Copper Solid-Liquid Interfaces
Authors: Lagraff John R. , Cruickshank Brandon J. , Gewirth Andrew A. 
Published: April 2011

ABSTRACTIt is extremely important to characterize the various bare copper surfaces in situ before any subsequent corrosion or deposition chemistry can be understood. In this paper, in situ Atomic Force Microscopy (AFM) was used to image the low-index faces of Cu single crystals in H2SO4 and HClO4 acidic solutions. Cu(100) surfaces exhibited potential-dependent c(2x2) adlayers in pH=1 solutions which were attributed to oxide (or hydroxide) overlayers. Images of Cu(1 10) obtained in pH 2.5-2.7 solutions revealed the growth of primarily [001] oriented (nxl) adlayer chain structures, where n is an integer. Preliminary measurements on Cu(111) did not reveal any adlayer structures between pH's of 1-3. The oxide monolayers on Cu(100) and Cu(110) crystals were observed in the thermodynamically forbidden region of the pH-potential phase diagram, which indicates that stable oxide adlayers develop prior to bulk oxide formation.
Electronic Structure and Bonding at Interfaces Between cvd Diamond and Silicon
Authors: Muller David A. , Tzou Yujiun , Raj Rishi , Silcox John 
Published: April 2011

ABSTRACTThe interfacial structure of CVD diamond grown on silicon was studied using spatially resolved electron energy loss spectroscopy (EELS) in a UHV STEM with a subnanometer probe size. Both the plasmon and core excitations in the bulk appear to be localized on this scale. Spatial maps of the different bonding configurations of carbon were obtained by forming images from transmitted electrons that had undergone energy losses characteristic of threefold and fourfold coordinated carbon. Films grown on both prescratched silicon and intermediate amorphous carbon layers were examined. In the latter case, diamond nucleation on a narrow sp2 a-C occurred. For diamond grown directly on silicon, at some regions of the interface, threefold coordinated defect states smaller than 1 nm are observed on the diamond side of the interface while at other regions along the interface the presence of an intermediate 2nm thick SiC layer preserves the fourfold coordination of the carbon.
Porous Silicon Luminescence Study by Imaging Methods: Relationship to Pore Dimensions
Authors: Kontkiewicz Anna , Kontkiewicz Andrzej M. , Sen Sidhartha , Wesolowski Marek , Lagowski Jacek , Edelman Piotr , Kowalewski Tomasz 
Published: April 2011

ABSTRACTIn a photoluminescence and surface photovoltage study of porous silicon films with crystallite dimensions assessed with the Atomic Force Microscope, we have found cases when the blue shifts of the luminescence spectrum and the optical absorption edge take place upon increasing crystallite dimensions, which is contrary to quantum size effects. Fourier transform infrared spectroscopy analysis of these samples shows significant differences in hydrogen and oxygen bonding, which imply that the origin of the luminescence is of chemical nature. Our results show that porous silicon luminescence is not a consequence of one mechanism, but rather results from several mechanisms with contributions depending on the chemistry and structure of porous silicon.
Composition and Strain Analysis of Semiconductor Heterostructures Using Thickness Fringes on Tem Images
Authors: Kakibayashi H. , Tsuneta R. , Nagata F. 
Published: April 2011

ABSTRACTComposition and strain depth profiles in heterostructures such as AlGaAs/GaAs, InGaAs/InP and SiGe/Si have been analyzed with a high resolution of 0.5 nm by using the thickness fringes in a transmission electron microscope image. This diagnostic method is found to successfully evaluate the compositional disordering caused by annealing multiple quantum well structures with abrupt interfaces, and determine the difference in strain distribution in the strained-layers with various lattice mismatches. Both the composition and strain depth-profiles are analyzed quantitatively by the image simulation based on the dynamical theory of electron diffraction. This method is also useful for sensitively detecting ion-implantation-induced defects.
Structural Investigation of NaNO3 Nanophase Confined in Porous Silica
Authors: Mu R. , Henderson D. O. , Jin F. 
Published: April 2011

ABSTRACTWe have demonstrated that thermal and vibrational investigations of sodium nitrate (NaNO3) physically confined in the porous silica hosts is an effective approach to mimic the solute clustering effects in aqueous solution. The results show that the structure of the NaNO3 confined in nanopores can be divided into three regions, i.e., the regular solid phase region, solution-like molecular aggregates region, and a new solid-like phase region. Depending upon the pore size of the porous host, the physical range of the three regions varies accordingly. For pore size d <2.5 nm, only the solution-like molecular aggregates phase remains.