bluuebunny/crossref_metadata_2025_split huggingface dataset:
Can We Build a Large-Scale Quantum Computer Using Semiconductor Materials?
Authors: Kane B. E. 
Published: February 2011

AbstractThe following article is based on the Symposium X presentation given by Bruce E. Kane (University of Maryland) at the 2004 Materials Research Society Spring Meeting in San Francisco. Quantum computing has the potential to revolutionize our ability to solve certain classes of difficult problems. A quantum computer is able to manipulate individual two-level quantum states (“qubits”) in the same way that a conventional computer processes binary ones and zeroes. Here, Kane discusses some of the most promising proposals for quantum computing, in which the qubit is associated with single-electron spins in semiconductors. While current research is focused on devices at the one- and two-qubit level, there is hope that cross-fertilization with advancing conventional computer technology will enable the eventual development of a large-scale (thousands of qubits) semiconductor quantum computer.The author focuses on materials issues that will need to be surmounted if large-scale quantum computing is to be realizable. He argues in particular that inherent fluctuations in doped semiconductors will severely limit scaling and that scalable quantum computing in semiconductors may only be possible at the end of the road of Moore's law scaling, when devices are engineered and fabricated at the atomic level.
Dye-Sensitized Solid-State Heterojunction Solar Cells
Authors: Grätzel Michael 
Published: February 2011

AbstractThe dye-sensitized solar cell (DSSC) provides a technically and economically viable alternative concept to present-day p–n junction photovoltaic devices. In contrast to conventional silicon systems, where the semiconductor assumes both the task of light absorption and charge carrier transport, these two functions are separated in DSSCs. The use of sensitizers having a broad absorption band in conjunction with wide-bandgap semiconductor films of mesoporous or nanocrystalline morphology permits harvesting a large fraction of sunlight. There are good prospects that these devices can attain the conversion efficiency of liquid-electrolyte-based dye-sensitized solar cells, which currently stands at 11%. In this article, we present the current state of the field, the realm of our review being restricted to the discussion of organic molecular hole conductors, which have demonstrated the best performance to date.
Smart Materials with Dynamically Controllable Surfaces
Authors: Lahann Joerg , Langer Robert 
Published: February 2011

AbstractRecent progress in various biotechnology fields, such as microfluidics, tissue engineering, and cellular biology, has created a great demand for substrates that can undergo defined remodeling with time. As a result, the latest research on materials with dynamically controllable surface properties has led to a variety of novel smart surface designs.
Cell-Sheet Engineering Using Intelligent Surfaces
Authors: Yang Joseph , Yamato Masayuki , Okano Teruo 
Published: February 2011

AbstractThe possibility of recreating various tissues and organs for the purpose of regenerative medicine has received much interest. However, the field of tissue engineering has been restricted by the limitations of conventional approaches. A method to circumvent the need for traditional scaffold-based technologies is cell-sheet engineering, which uses temperature-responsive culture dishes. These surfaces, which are created by grafting the temperature-responsive polymer poly(N-isopropylacrylamide) onto ordinary culture dishes, enable the non-invasive harvesting of cells as intact sheets by simple temperature reduction. This article reviews current research on the applications of cell-sheet engineering for the reconstruction of various tissues, as well as the intelligent surfaces used by this novel technology.
Bioactive Patterns at the 100-nm Scale Produced Using Multifunctional Physisorbed Monolayers
Authors: Vörös Janos , Blättler Thomas , Textor Marcus 
Published: February 2011

AbstractRecently, a variety of patterning techniques have reached feature sizes of 100 nm or less, a size range very relevant to biology. Proteins, vesicles, and macromolecular assemblies can now be handled and specifically placed onto predefined artificial patterns, triggering defined functions in cells and revealing the details of cell–surface interactions. Simultaneously, novel surface chemistries have been developed that are able to induce specific bioresponses (e.g., mimicking the features of the extracellular matrix) and at the same time suppress the nonspecific effects of complex biological solutions. This article reviews the basic principles and properties of multifunctional physisorbed monolayers that can be used in combination with nanopatterning techniques to create biologically relevant surface features. Furthermore, selected examples of nanopatterns created by novel combinations of different top-down and bottom-up approaches are presented, including systems with specific bioligands, proteins, vesicles, and cells.
Advances in Silicon Carbide Electronics
Authors: Zolper J. C. , Skowronski M. 
Published: February 2011

AbstractAfter substantial investment in research and development over the last decade, silicon carbide materials and devices are coming of age. The concerted efforts that made this possible have resulted in breakthroughs in our understanding of materials issues such as compensation mechanisms in high-purity crystals, dislocation properties, and the formation of SiC/SiO2 interfaces, as well as device design and processing. The progress accomplished over the last eight years in SiC-based electronic materials is summarized in this issue of MRS Bulletin.
Bulk Crystal Growth, Epitaxy, and Defect Reduction in Silicon Carbide Materials for Microwave and Power Devices
Authors: Sumakeris J. J. , Jenny J. R. , Powell A. R. 
Published: February 2011

AbstractWe discuss continuing materials technology improvements that have transformed silicon carbide from an intriguing laboratory material into a premier manufacturable semiconductor technology. This advancement is demonstrated by reduced micropipe densities as low as 0.22 cm−2 on 3-in.-diameter conductive wafers and 16 cm−2 on 100-mm-diameter conductive wafers. For high-purity semi-insulating materials, we confirm that the carbon vacancy is the dominant deep-level trapping state, and we report very consistent cross-wafer activation energies derived from temperature-dependent resistivity.Warm-wall and hot-wall SiC epitaxy platforms are discussed in terms of capability and applications. Specific procedures that essentially eliminate forward-voltage drift in bipolar SiC devices are presented in detail.
Interface Passivation for Silicon Dioxide Layers on Silicon Carbide
Authors: Dhar Sarit , Wang Shurui , Williams John R. , Pantelides Sokrates T. , Feldman Leonard C. 
Published: February 2011

AbstractSilicon carbide is a promising semiconductor for advanced power devices that can outperform Si devices in extreme environments (high power, high temperature, and high frequency). In this article, we discuss recent progress in the development of passivation techniques for the SiO2/4H-SiC interface critical to the development of SiC metal oxide semiconductor field-effect transistor (MOSFET) technology. Significant reductions in the interface trap density have been achieved, with corresponding increases in the effective carrier (electron) mobility for inversion-mode 4H-SiC MOSFETs. Advances in interface passivation have revived interest in SiC MOSFETs for a potentially lucrative commercial market for devices that operate at 5 kV and below.
Silicon Carbide Power Field-Effect Transistors
Authors: Zhao Jian H. 
Published: February 2011

AbstractSilicon carbide power field-effect transistors, including power vertical-junction FETs (VJFETs) and metal oxide semiconductor FETs (MOSFETs), are unipolar power switches that have been investigated for high-temperature and high-power-density applications. Recent progress and results will be reviewed for different device designs such as normally-OFF and normally-ON VJFETs, double-implanted MOSFETs, and U-shaped-channel MOSFETs. The advantages and disadvantages of SiC VJFETs and MOSFETs will be discussed. Remaining challenges will be identified.
SiC MESFETs for High-Frequency Applications
Authors: Sriram S. , Ward A. , Henning J. , Allen S. T. 
Published: February 2011

AbstractSignificant progress has been made in the development of SiC metal semiconductor field-effect transistors (MESFETs) and monolithic microwave integrated-circuit (MMIC) power amplifiers for high-frequency power applications. Three-inch-diameter high-purity semi-insulating 4H-SiC substrates have been used in this development, enabling high-volume fabrication with improved performance by minimizing surface- and substrate-related trapping issues previously observed in MESFETs. These devices exhibit excellent reliability characteristics, with mean time to failure in excess of 500 h at a junction temperature of 410°C. A sampling of these devices has also been running for over 5000 h in an rf high-temperature operating-life test, with negligible changes in performance. High-power SiC MMIC amplifiers have also been demonstrated with excellent yield and repeatability. These MMIC amplifiers show power performance characteristics not previously available with conventional GaAs technology. These developments have led to the commercial availability of SiC rf power MESFETs and to the release of a foundry process for MMIC fabrication.
Hybrid Organic–Nanocrystal Solar Cells
Authors: Milliron Delia J. , Gur Ilan , Alivisatos A. Paul 
Published: February 2011

AbstractRecent results have demonstrated that hybrid photovoltaic cells based on a blend of inorganic nanocrystals and polymers possess significant potential for low-cost, scalable solar power conversion. Colloidal semiconductor nanocrystals, like polymers, are solution processable and chemically synthesized, but possess the advantageous properties of inorganic semiconductors such as a broad spectral absorption range and high carrier mobilities. Significant advances in hybrid solar cells have followed the development of elongated nanocrystal rods and branched nanocrystals, which enable more effective charge transport. The incorporation of these larger nanostructures into polymers has required optimization of blend morphology using solvent mixtures. Future advances will rely on new nanocrystals, such as cadmium telluride tetrapods, that have the potential to enhance light absorption and further improve charge transport. Gains can also be made by incorporating application-specific organic components, including electroactive surfactants which control the physical and electronic interactions between nanocrystals and polymer.
Shape-Controlled Synthesis and Surface Plasmonic Properties of Metallic Nanostructures
Authors: Xia Younan , Halas Naomi J. 
Published: February 2011

AbstractThe interaction of light with free electrons in a gold or silver nanostructure can give rise to collective excitations commonly known as surface plasmons. Plasmons provide a powerful means of confining light to metal/dielectric interfaces, which in turn can generate intense local electromagnetic fields and significantly amplify the signal derived from analytical techniques that rely on light, such as Raman scattering. With plasmons, photonic signals can be manipulated on the nanoscale, enabling integration with electronics (which is now moving into the nano regime). However, to benefit from their interesting plasmonic properties, metal structures of controlled shape (and size) must be fabricated on the nanoscale. This issue of MRS Bulletin examines how gold and silver nanostructures can be prepared with controllable shapes to tailor their surface plasmon resonances and highlights some of the unique applications that result, including enhancement of electromagnetic fields, optical imaging, light transmission, colorimetric sensing, and nanoscale waveguiding.
Shape-Controlled Synthesis of Silver and Gold Nanostructures
Authors: Wiley Benjamin , Sun Yugang , Chen Jingyi , Cang Hu , Li Zhi-Yuan , Li Xingde , Xia Younan 
Published: February 2011

AbstractThis article provides a brief account of solution-phase methods that generate silver and gold nanostructures with well-controlled shapes. It is organized into five sections: The first section discusses the nucleation and formation of seeds from which nanostructures grow. The next two sections explain how seeds with fairly isotropic shapes can grow anisotropically into distinct morphologies. Polyol synthesis is selected as an example to illustrate this concept. Specifically, we discuss the growth of silver nanocubes (with and without truncated corners), nanowires, and triangular nanoplates. In the fourth section, we show that silver nanostructures can be transformed into hollow gold nanostructures through a galvanic replacement reaction. Examples include nanoboxes, nanocages, nanotubes (both single- and multi-walled), and nanorattles. The fifth section briefly outlines a potential medical application for gold nanocages.We conclude with some perspectives on areas for future work.
Playing with Plasmons: Tuning the Optical Resonant Properties of Metallic Nanoshells
Authors: Halas Naomi 
Published: February 2011

AbstractNanoshells, concentric nanoparticles consisting of a dielectric core and a metallic shell, are simple spherical nanostructures with unique, geometrically tunable optical resonances. As with all metallic nanostructures, their optical properties are controlled by the collective electronic resonance, or plasmon resonance, of the constituent metal, typically silver or gold. In striking contrast to the resonant properties of solid metallic nanostructures, which exhibit only a weak tunability with size or aspect ratio, the optical resonance of a nanoshell is extraordinarily sensitive to the inner and outer dimensions of the metallic shell layer. The underlying reason for this lies beyond classical electromagnetic theory, where plasmon-resonant nanoparticles follow a mesoscale analogue of molecular orbital theory, hybridizing in precisely the same manner as the individual atomic wave functions in simple molecules. This plasmon hybridization picture provides an essential “design rule” for metallic nanostructures that can allow us to effectively predict their optical resonant properties. Such a systematic control of the far-field optical resonances of metallic nanostructures is accomplished simultaneously with control of the field at the surface of the nanostructure. The nanoshell geometry is ideal for tuning and optimizing the near-field response as a stand-alone surface-enhanced Raman spectroscopy (SERS) nanosensor substrate and as a surface-plasmon-resonant nanosensor.Tuning the plasmon resonance of nanoshells into the near-infrared region of the spectrum has enabled a variety of biomedical applications that exploit the strong optical contrast available with nanoshells in a spectral region where blood and tissue are optimally transparent.
Spintronics: The Future of Data Storage?
Authors: Wolf S.A. , Treger Daryl , Chtchelkanova Almadena 
Published: February 2011

AbstractReasearch and technology developments in the field of spintronics have grown tremendously in the past 10-15 years and already have had a major impact on the data storage industry.The future looks even brighter, as many new spintronic discoveries have been recently made that promise an even bigger impact in the future.This article summarizes the past accomplishments, describes some of the major discoveries that will have a lasting impact on the field, and discusses some of the technologies that may revolutionize data storage in the next decade.
Magnetic Tape: The Challenge of Reaching Hard-Disk-Drive Data Densities on Flexible Media
Authors: Dee Richard H. 
Published: February 2011

AbstractBy the end of 2006, the areal density of magnetic recording on tape will approach that seen in hard disk drives of the early to mid-1990s.These operating conditions are reviewed in relation to the operating conditions deemed necessary for the future of magnetic data storage on tape.What results is a clear set of tasks, encompassing both materials and systems architecture issues, to achieve very high-density data storage on magnetic tape, leading to 10 Tbyte tape cartridge capacities and higher.The key to achieving on tape the areal densities of tens to hundreds of Gbit in.2, common in hard disk drives (HDDs), lies primarily in the properties of the medium itself.As for volumetric density of the storage entity, HDDs and tape cartridges are roughly equivalent.The mechanical dimensional uncertainties that accompany the use of flexible, as opposed to rigid, media means that both the mechanical and magnetic properties of materials play a key role in the future of tape.The need for new architectures to overcome the track placement problem that results from increasing track density on flexible media are reviewed, as well as the “particles in a binder” concept that has served so well as the physical basis of tape media over the past 50 years.
Macroelectronics
Authors: Reuss Robert H. , Hopper Darrel G. , Park Jae-Geun 
Published: February 2011

AbstractAs revolutionary as microelectronics has been as a technology, there are functions that it does not address. Microelectronics focuses on ever-smaller integrated circuits (ICs) in ever-fewer square millimeters of space to increase clock speeds and decrease the power required for computer processing functions. However, applications requiring control, communications, computing, and sensing over a large area are difficult or costprohibitive to achieve because of the material incompatibilities of traditional ICs with structures, materials, and manufacturing technology. Macroelectronics addresses these applications with the aim of providing active control circuitry in situ over areas of many square meters for displays, solar panels, x-ray imagers, surface measurements, structural shape control, vehicle health monitoring, and other large-system applications. The materials challenges of macroelectronics integrated circuits (MEICs) reviewed in this issue include lightweight flexible substrates, thin-film transistors (TFTs) with IC or near-IC performance, modeling, and manufacturing technology. Compatible component materials, flexible substrates, processing conditions, host system composition, and functionality provide grand challenges that are just beginning to be addressed by researchers.
Development of High-Performance Organic Thin-Film Transistors for Large-Area Displays
Authors: Lee Sangyun , Koo Bonwon , Park Jae-Geun , Moon Hyunsik , Hahn Jungseok , Kim Jong Min 
Published: February 2011

AbstractOrganic thin-film transistors (OTFTs) are considered indispensable in applications requiring flexibility, large area, low processing temperature, and low cost. Key challenges to be addressed include developing solution-processable gate dielectric materials that form uniform films over large areas and exhibit excellent insulating properties, reducing contact resistance at interfaces between organic semiconductors and electrodes, and optimizing the patterning of organic semiconductors. High-performance pentacene-based OTFTs have been reported with polymeric gate dielectrics and indium tin oxide source/drain electrodes. Using such OTFT backplates, a 15-in. 1024 X 768 pixel full-color active-matrix liquid-crystal display (AMLCD) and a 4.5-in. 192 X64 pixel active-matrix organic light-emitting diode (AMOLED) have been fabricated.
Toward Manufacturing Low-Cost, Large-Area Electronics
Authors: Chason Marc , Gamota Daniel R. , Brazis Paul W. , Kalyanasundaram Krishna , Zhang Jie , Lian Keryn K. , Croswell Robert 
Published: February 2011

AbstractDevelopments originally targeted toward economical manufacturing of telecommunications products have planted the seeds for new opportunities such as low-cost, large-area electronics based on printing technologies. Organic-based materials systems for printed wiring board (PWB) construction have opened up unique opportunities for materials research in the fabrication of modular electronic systems.The realization of successful consumer products has been driven by materials developments that expand PWB functionality through embedded passive components, novel MEMS structures (e.g., meso-MEMS, in which the PWB-based structures are at the milliscale instead of the microscale), and microfluidics within the PWB. Furthermore, materials research is opening up a new world of printed electronics technology, where active devices are being realized through the convergence of printing technologies and microelectronics.
Characterization of Mechanical and Thermal Properties Using Ultrafast Optical Metrology
Authors: Antonelli G. Andrew , Perrin Bernard , Daly Brian C. , Cahill David G. 
Published: February 2011

AbstractUltrafast lasers have long been used to study the dynamics of fast optical, electronic, and chemical processes in materials. These tools can also be used in a variety of optical pump and probe spectroscopies to generate and detect acoustic signals with frequencies on the order of 100 GHz, and to generate and detect thermal waves with penetration depths on the scale of nanometers. The short wavelengths of these probes make them ideal for the study of the mechanical and thermal properties of thin films, their interfaces, and nanostructures. We describe the picosecond-laser acoustics technique and demonstrate how it can be used to extract the elastic constants and the adhesion of thin films and probe the normal modes of vibration of nanostructures. The thermal properties of thin films are also accessible through time-domain thermoreflectance. Since the mechanical and thermal properties can be obtained quickly on micrometer-scale regions of a sample, spatial mapping of the properties is also possible.
Ultrafast Imaging of Materials: Exploring the Gap of Space and Time
Authors: King Wayne E. , Armstrong Michael , Malka Victor , Reed Bryan W. , Rousse Antoine 
Published: February 2011

AbstractThe materials science community is poised to take advantage of new technologies that add unprecedented time resolution to already existing spatial-resolution capabilities. In the same way that chemists and biologists are using ultrafast optical, photon, and particle techniques to reveal transition pathways, materials scientists can expect to use variations of these methods to probe the most fundamental aspects of complex transient phenomena in materials. The combination of high-spatial-resolution imaging with high time resolution is critical because it enables the observation of specific phenomena that are important to developing fundamental understanding. Such a capability is also important because it enables experiments that are on the same time and length scales as recent high-performance computer simulations. This article describes several new techniques that have great potential for broader application in materials science, including electron, x-ray, and γ-ray imaging.
Ultrafast Processes for Bulk Modification of Transparent Materials
Authors: Itoh Kazuyoshi , Watanabe Wataru , Nolte Stefan , Schaffer Chris B. 
Published: February 2011

AbstractWhen a femtosecond laser pulse is focused inside a transparent material, the optical intensity in the focal volume can become high enough to induce permanent structural modifications such as a refractive index change or the formation of a small vacancy. Thus, one can micromachine structures inside the bulk of a transparent material in three dimensions. We review the mechanisms of and techniques for bulk modification of transparent materials using femtosecond laser pulses and discuss the fabrication of photonic and other structures in transparent materials, including waveguides, couplers, gratings, diffractive lenses, optical data storage, and microfluidic channels.