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MRS Online Proceedings Library 2011年第1期334卷 239-244页

作者： Wen-Shryang Liu Gregory B. Raupp Science and Engineering of Materials Program Center for Solid State Electronics Research Arizona State University Tempe USA Department of Chemical Bio and Materials Engineering Center for Solid State Electronics Research Arizona State University Tempe USA

Temperature programmed desorption (TPD) studies in ultra high vacuum revealed that diethyltellurium (DETe) and dimethylcadmium (DMCd) adsorb weakly on clean Si(100) and desorb upon heating without decomposing. These precursors adsorb both weakly and strongly on CdTe(111)A, with DMCd exhibiting the stronger interaction with the surface than DETe. Dimethylcadmium partially decomposes to produce Cd adatoms; a large fraction of the excess Cd atoms desorb upon heating. In contrast, DETe desorbs without decomposing, suggesting that the rate limiting step in CdTe MOCVD on CdTe(111)A is surface decomposition of the tellurium alkyl.

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Phosphor Synthesis Routes and their Effect on the Performance of Garnet Phosphors at Low-Voltages

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MRS Online Proceedings Library 2011年第1期424卷 409-414页

作者： L. E. Shea J. McKittrick and M. L. F. Phillips Department of Applied Mechanics & Engineering Sciences and Materials Science Program University of California San Diego La Jolla USA Sandia National Laboratories Albuquerque USA

Garnet phosphors have potential for use in field emission displays (FEDs). Greenemitting Gd3Ga5O12:Tb (GGG:Tb) and Y3Al5O12:Tb (YAG:Tb) are possible alternatives to ZnO:Zn, because of their excellent resistance to burn, low-voltage efficiency, (3.5 lm/W from GGG:Tb at 800 V), and saturation resistance at high power densities. Hydrothermal and combustion synthesis techniques were employed to improve the low-voltage efficiency of YAG:Tb, and Y3Ga5O12:Tb (YGG:Tb). Synthetic technique did not affect low-voltage (100-1000 V) efficiency, but affected the particle size, morphology, and bum resistance. The small particle size phosphors obtained via hydrothermal (<1 µm) and combustion reactions (<1 µm) would benefit projection TV, high-definition TV (HDTV), and heads-up displays (HUDs), where smaller pixel sizes are required for high resolution.

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Heat conduction properties of graphene: Prospects of thermal management applications

Heat conduction properties of graphene: Prospects of thermal...

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IEEE Symposium on Semiconductor Thermal Measurement and Management (SEMI-THERM)

作者： Alexander A. Balandin Nano-Device Laboratory Department of Electrical Engineering and Materials Science and Engineering Program Bourns College of Engineering University of California Riverside Riverside CA USA

As the electronic industry moves towards few-nanometer-scale CMOS and 3D IC designs thermal management becomes crucially important for achieving high performance and reliability of advanced electronic chips. One approach for mitigating the self-heating problems is finding materials with very high thermal conductivity, which can be integrated with Si ICs or used as fillers in the next generation of the thermal interface materials (TIMs). In 2008, we discovered that graphene reveals extremely high intrinsic thermal conductivity, which can exceed that of bulk graphite. To measure the thermal conductivity of an object with a thickness of just one atomic layer, we developed an original experimental technique and applied it to graphene flake suspended across trenches in Si wafers. In this technique, the micro-Raman spectrometer performed the function of a thermometer measuring the local temperature rise from the shift in the spectral position of the Raman G peak. We explained the fact that the intrinsic thermal conductivity of graphene can be larger than that of graphite by the fundamental difference in the low-energy phonon transport in 2D graphene and 3D graphite. The extremely high thermal conductivity of “free” suspended graphene does not mean that it will be automatically preserved when graphene is incorporated inside semiconductor chips or composite TIMs. Thermal conductivity of graphene layers depends strongly on their geometrical size, coupling to the adjacent substrate or capping layers, edges roughness and defect concentration. I will overview the experimental and theoretical results for the thermal conductivity evolution of the few-layer graphene (FLG) considering two limiting cases of the phonon transport limited by the intrinsic and extrinsic effects. The use of graphene as interconnects and heat spreaders in advanced 2D and 3D computer chips will also be discussed. The last section of the talk will have a description of the data for graphene TIM materials. W

关键词： Thermal conductivity Conductivity materials Three dimensional displays Thermal management of electronics Temperature measurement Thermal engineering

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Novel arsenic ion-imprinted polymer: Simultaneous removal As(III) and As(V) from water

Novel arsenic ion-imprinted polymer: Simultaneous removal As...

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World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability

作者： Kalita, Harjyoti Chisholm, Bret Bezbaruah, Achintya N. Materials and Nanotechnology Program North Dakota State University Fargo ND 58105 United States Center for Nanoscale Science and Engineering North Dakota State University Fargo ND 58105 United States Department of Civil Engineering North Dakota State University Fargo ND 58105 United States

ISBN: (纸本)9780784411735

In view of the extreme toxicity of arsenic on human and other living organism the U.S. Environmental Protection Agency (U.S. EPA) has fixed the maximum contaminant level (MCL) for arsenic as 10 ppb in drinking water. We now propose a novel method for the treatment of arsenic that is based on emerging ion-imprinting technology. The new product is expected to have the ability to remove both As(III) and As(V) simultaneously from water. Our ongoing experiments indicate that it can remove As(V) very efficiently. Experiments with As(III) are proposed in the near future. Results demonstrate that the ion imprinted polymer (IIP) has the capability to remove arsenic from water to below the U.S. MCL. ICP-OES and FT-IR have been used to analyze arsenic and monitor the IIP synthesis process, respectively. The new IIP is expected to be a very simple, reliable, and cost-effective to remove aqueous arsenic. © 2011 ASCE.

关键词： Cost effectiveness

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Pressure Assisted Crystallization of MnAl Thin Films

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MRS Online Proceedings Library (OPL) 2011年第1期695卷 L13.5.1-L13.5.1页

作者： Gregory A. Fischer M. Lea Rudee Vitali F. Nesterenko Sastry Indrakanti Graduate Program in Materials Science/Center for Magnetic Recording Research University of California at San Diego La Jolla CA. 92093-0401 Graduate Program in Materials Science/Department of Mechanical and Aerospace Engineering University of California at San Diego La Jolla CA. 92093-0411

The effect of hot isostatic pressure processing (HIP) on MnAl films has been compared to vacuum annealing for the purpose of obtaining substantial amounts of tau phase MnAl in films under 200 nm. Films were deposited by dc sputtering from both MnAlNiC an MnAl targets. As-deposited films were nearly amorphous. Post deposition annealing in vacuum produced only small amounts of the ferromagnetic tau-phase in films thinner than 200 *** all instances, regardless of substrate and sputtering target, the use of HIP in place of vacuum annealing increased the degree of crystallinity of the samples when compared to those annealed in vacuum. For the 100 nm samples deposited from the MnAlNiC target, these changes in crystallinity were accompanied by changes in the M-H loops of the samples. MnAlNiC HIP samples had improved magnetic properties compared to those of equal thickness annealed in vacuum. The 100 nm HIP sample sputtered from the MnAl target also showed an increase in moment, though the changes were not as dramatic as those seen in the samples sputtered from the MnAlNiC *** 50 nm films from both targets also showed a change in crystallinity when compared to vacuum annealed samples. These films, unlike the 100 nm films, had ferromagnetic properties that were no better than those of the vacuum annealed samples. This suggests that while the 2 kbar of pressure used in this study assists in the formation of tau-phase in 100 nm films, the appropriate pressure for forming tau-phase in 50 nm films is yet to be determined.

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Comprehensive analysis of compositional interface fluctuations in planar lipid bilayer membranes

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Physical Review E 2011年第5期84卷 051903-051903页

作者： Tao Han Mikko Haataja Department of Mechanical and Aerospace Engineering Princeton Institute for the Science and Technology of Materials (PRISM) and Program in Applied and Computational Mathematics (PACM) Princeton University Princeton New Jersey 08544 USA

In this paper we present a comprehensive analysis of line tension-driven compositional interface fluctuations in planar lipid bilayer membranes. Our starting point is the advective Cahn-Hilliard equation for the local lipid composition in symmetric membranes, which explicitly incorporates both advective and diffusive lipid transport processes, and which is coupled to the continuum hydrodynamic equations governing the flow behavior of the membrane and surrounding solvent with finite subphase thickness. In order to extract the interface dynamics from the continuum phase-field formalism, we first derive the appropriate sharp-interface limit equations. We then carry out a linear perturbation analysis for the relaxational dynamics of small-amplitude sinusoidal interface fluctuations to yield the general dispersion relation ωk as a function of perturbation wave number k. The resulting expression incorporates the effects of diffusive and advective lipid transport processes within the membrane, viscous or viscoelastic membrane properties, coupling between membrane and solvent, and inertial effects within the membrane and solvent. It is shown that previously considered scenarios naturally emerge as limiting cases of the general result. Furthermore, we discuss two additional scenarios amenable to analysis, one in which the inertia of the solvent is relevant, and another one in which the membrane displays significant viscoelastic properties. Finally, we numerically evaluate the general dispersion relation for three representative model membrane systems.

关键词： BILAYER lipid membranes FLUCTUATIONS (Physics) PERTURBATION (Mathematics) VISCOELASTICITY HYDRODYNAMICS

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Higher-k dielectrics and conductive oxide electrodes for next generation DRAMs with a design rule of <20 nm#

Higher-k dielectrics and conductive oxide electrodes for nex...

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International Symposium Semiconductor Device Research (ISDRS)

作者： Jeong Hwan Han Woongkyu Lee Sang Woon Lee Cheol Seong Hwang WCU Hybrid Materials Program Department of Materials Science and Engineering Inter-university Semiconductor Research Center Seoul National University Seoul South Korea

Dynamic random access memory (DRAM) is used as the main memory in every personal computer, due to its high density, high speed and efficient memory function. The ever-shrinking dimensions of DRAM cells with increasing packing density made the cell's capacitor size to be smaller. For successful operation of DRAM, a large cell capacitance (~ 25 fF) and low leakage current (10 -7 A/cm 2 or 1 fA/cell) are required. In a traditional Si-based capacitor, the target cell capacitance has been achieved by increasing the surface area of the capacitor. More recently, innovations have been made by development of the component materials. A metal electrode, TiN or Ru, and a dielectric material with a moderate-k value (k is the relative dielectric constant), such as HfO 2 (k ~ 25) and ZrO 2 (k ~ 40), are being explored in giga-bit scale DRAMs. The minimum achievable t ox is ~ 0.7 nm for ZrO 2 which is being used currently in DRAM industry. However, the technology road map for memory devices states that t ox of less than 0.45 nm is necessary for the DRAMs with a design rule of 3 (STO) and (Ba, Sr)TiO 3 were reported to exhibit k values of several hundreds. However, growth of these films showed very slow growth rate and much more complicated processes than growth of binary oxide with the atomic layer deposition (ALD) technique which is a method of choice for the growth of the dielectric films and electrodes in microelectronic devices. Therefore, material and process innovations are necessary for next generation DRAM capacitors.

关键词： Films Electrodes Capacitors Random access memory Substrates Strontium

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Model for biological communication in a nanofabricated cell-mimic driven by stochastic resonance

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Nano Communication Networks 2011年第1期2卷 39-49页

作者： Karig, David K. Siuti, Piro Dar, Roy D. Retterer, Scott T. Doktycz, Mitchel J. Simpson, Michael L. Center for Nanophase Materials Sciences Oak Ridge National Laboratory Bethel Valley Road Oak Ridge TN 37831 United States Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831 United States Graduate Program in Genome Science and Technology University of Tennessee Knoxville TN 37996 United States Department of Physics and Astronomy University of Tennessee Knoxville TN 37996-2010 United States Department of Materials Science and Engineering University of Tennessee Knoxville TN 37996-2010 United States Center for Environmental Biotechnology University of Tennessee Knoxville TN 37996-2010 United States

Cells offer natural examples of highly efficient networks of nanomachines. Accordingly, both intracellular and intercellular communication mechanisms in nature are looked to as a source of inspiration and instruction for engineered nanocommunication. Harnessing biological functionality in this manner requires an interdisciplinary approach that integrates systems biology, synthetic biology, and nanofabrication. Here, we present a model system that exemplifies the synergism between these realms of research. We propose a synthetic gene network for operation in a nanofabricated cell mimic array that propagates a biomolecular signal over long distances using the phenomenon of stochastic resonance. Our system consists of a bacterial quorum sensing signal molecule, a bistable genetic switch triggered by this signal, and an array of nanofabricated cell mimic wells that contain the genetic system. An optimal level of noise in the system helps to propagate a time-varying AHL signal over long distances through the array of mimics. This noise level is determined both by the system volume and by the parameters of the genetic network. Our proposed genetically driven stochastic resonance system serves as a testbed for exploring the potential harnessing of gene expression noise to aid in the transmission of a time-varying molecular signal. © 2011.

关键词： Gene expression

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Microfluidic actuators based on infrared-light responsive PNIPAAm hydrogel nanocomposite incorporating graphene-oxide

Microfluidic actuators based on infrared-light responsive PN...

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International Solid-State Sensors, Actuators and Microsystems Conference

作者： Lo, Chi-Wei Zhu, Difeng Jiang, Hongrui Materials Science Program University of Wisconsin-Madison WI 53706 United States Department of Electrical and Computer Engineering University of Wisconsin-Madison WI 53706 United States Eye Research Institute University of Wisconsin Madison Madison WI 53706 United States

ISBN: (纸本)9781457701573

In lab-on-a-chip systems, microactuators are critical to control the flow within the microchannels. Most of the current actuators require hardware connection (electromagnetic, thermopneumatic actuators, etc.) within the channels, thus significantly increasing the system complexity. Remotely controllable actuators would greatly simplify the system. We demonstrate nanocomposite microfluidic actuators remotely controlled by infrared (IR) light. These actuators are fabricated out of thermo-responsive poly-N- isopropylacrylamide (PNIPAAm) nanocomposite hydrogels incorporated with glycidyl methacylate functionalized graphene-oxide (GO-GMA). Two example devices were realized implementing such actuators: a microvalve and a tunable liquid microlens. © 2011 IEEE.

关键词： Hydrogels

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Nanosecond Dynamics of Ferroelectric/Dielectric Superlattices

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Physical Review Letters 2011年第5期107卷 055501-055501页

作者： Ji Young Jo Pice Chen Rebecca J. Sichel Sara J. Callori John Sinsheimer Eric M. Dufresne Matthew Dawber Paul G. Evans Department of Materials Science and Engineering and Materials Science Program University of Wisconsin–Madison Madison Wisconsin 53706 USA Department of Physics and Astronomy Stony Brook University Stony Brook New York 11794 USA Advanced Photon Source Argonne National Laboratory Argonne Illinois 60439 USA

The nanosecond response of a PbTiO3/SrTiO3 ferroelectric/dielectric superlattice to applied electric fields is closely linked to the dynamics of striped domains of the remnant polarization. The intensity of domain satellite reflections observed with time-resolved x-ray microdiffraction decays in 5–100 ns depending on the magnitude of the electric field. The piezoelectric response of the superlattice within stripe domains is strongly suppressed due to electromechanical clamping between adjacent regions of opposite polarization. Regions of the superlattice that have been switched into a uniform polarization state by the applied electric field, however, exhibit piezoelectricity during the course of the switching process. We propose a switching model different from previous models of the switching of superlattices, based instead on a spatially heterogeneous transformation between striped and uniform polarization states.

关键词： Polarization

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