bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanofunctional Materials in Cancer Research: Challenges, Novel Methods, and Emerging Applications
Authors: Nagahara Larry A. , Ferrari Mauro , Grodzinski Piotr 
Published: February 2011

AbstractDespite recent progress in the treatment of cancer, far too many cases are still diagnosed only after tumors have metastasized. As a result, patients with cancer face a grim prognosis and often need to endure toxic and uncomfortable whole-body chemotherapy and/or other radiation treatments with the hope that their cancers will be eliminated. If the disease can be detected early enough, statistics have shown that the burden of cancer is drastically reduced. Nanotechnology applied to cancer, by way of nanofunctional materials, is in a unique position to significantly transform the way the disease is diagnosed, imaged, and treated and is the focus of this issue of MRS Bulletin. Materials research in nanotechnology is already successfully implemented in several applications. For instance, photocatalysis using TiO2 nanoparticles is becoming the dominant method for the “self-cleaning” of material surfaces such as glass, ceramics, and fabrics. The nanomaterial carbon nanotubes is a promising candidate in sensor technology and field-emission technology. Our goal is to illustrate the promising new methods being developed in the research community and the challenges that need to be overcome in order to reach clinical utility. More importantly, we hope this issue helps educate and invoke the materials science community to tackle some of the hard issues in diagnosing and treating this disease.
Gold-Based Magneto/Optical Nanostructures: Challenges for In Vivo Applications in Cancer Diagnostics and Therapy
Authors: Melancon Marites P. , Lu Wei , Li Chun 
Published: February 2011

AbstractNanoparticles with a gold shell and iron core have unique optical and magnetic properties that can be utilized for simultaneous detection and treatment strategies. Several nanoparticles have been synthesized and show an ability to mediate a variety of potential applications in biomedicine, including cancer molecular optical and magnetic resonance imaging, controlled drug delivery, and photothermal ablation therapy. However, to be effective, these nanoparticles must be delivered efficiently into their targets. In this review, we will provide an updated summary of the gold-shelled magnetic nanoparticles that have been synthesized, methods for characterization, and their potential for cancer diagnosis and treatment. We will also discuss the biological barriers that need to be overcome for the effective delivery of these nanoparticles. The desired nanoparticle characteristics needed to evade these biological barriers, such as size, shape, surface charge, and surface coating are also explained.
Materials Science of High-Level Nuclear Waste Immobilization
Authors: Weber William J. , Navrotsky Alexandra , Stefanovsky Sergey , Vance Eric R. , Vernaz Etienne 
Published: February 2011

AbstractWith the increasing demand for the development of nuclear power comes the responsibility to address the issue of waste, including the technical challenges of immobilizing high-level nuclear wastes in stable solid forms for interim storage or disposition in geologic repositories. The immobilization of high-level nuclear wastes has been an active area of research and development for over 50 years. Borosilicate glasses and complex ceramic composites have been developed to meet many technical challenges and current needs, although regulatory issues, which vary widely from country to country, have yet to be resolved. Cooperative international programs to develop advanced proliferation-resistant nuclear technologies to close the nuclear fuel cycle and increase the efficiency of nuclear energy production might create new separation waste streams that could demand new concepts and materials for nuclear waste immobilization. This article reviews the current state-of-the-art understanding regarding the materials science of glasses and ceramics for the immobilization of highlevel nuclear waste and excess nuclear materials and discusses approaches to address new waste streams.
Ultimate Scaling of CMOS Logic Devices with Ge and III–V Materials
Authors: Heyns M. , Tsai W. 
Published: February 2011

AbstractOver the years, many new materials have been introduced in advanced complementary metal oxide semiconductor (CMOS) processes in order to continue the trend of reducing the gate length and increasing the performance of CMOS devices. This is clearly evidenced in the International Technology Roadmap for Semiconductors (ITRS), which indicates the requirements and technological challenges in the microelectronics industry in various technology nodes. Every new technology node, characterized by the minimal device dimensions that are used, has required innovations in new materials and transistor design. The introduction of deposited high-κ gate dielectrics and metal gates as replacements for the thermally grown SiO2 and poly-Si electrode was a major challenge that has been met in the transition toward the 32 nm technology node since it replaced the heart of the metal oxide semiconductor structure. For the next generation of technology nodes, even bigger hurdles will need to be overcome, since new device structures and high-mobility channel materials such as Ge and III–V compounds might be needed, according to the ITRS roadmap, to meet the power and performance specifications of the 16 nm CMOS node and beyond. The basic properties of these high-mobility channel materials and their impact on the device performance have to be fully understood to allow process integration and full-scale manufacturing. In addition to thermal stability, compatibility with other materials, electronic transport properties, and especially the passivation of electronically active defects at the interface with a high-κ dielectric, are enormous challenges. Many encouraging results have been obtained, but the stringent demands in terms of electrical performance and oxide thickness scaling needed for highly scaled CMOS devices are not yet fully met. Other areas where breakthroughs will be needed are the formation of low-resistivity contacts, especially on III–V materials, and III–V materials suited for pMOS channels. An overview of the major successes and remaining critical issues in the materials research on high-mobility channel materials for advanced CMOS devices is given in this issue of MRS Bulletin.
InGaAs Metal Oxide Semiconductor Devices with Ga2O3(Gd2O3) High-κ Dielectrics for Science and Technology beyond Si CMOS
Authors: Hong M. , Kwo J. , Lin T.D. , Huang M.L. 
Published: February 2011

AbstractAn overview is given on scientific and device advances for InGaAs metal oxide semiconductor heterostructures and inversion channel metal oxide semiconductor field-effect transistors (MOSFETs), with emphasis on results using ultrahigh vacuum-deposited Ga2O3(Gd2O3) [GGO] as high-κ dielectrics. Regardless of the approaches used to deposit high-κ dielectrics on InGaAs, critical material and electrical parameters of fabricating inversion channel InGaAs MOSFETs must be ready for complementary MOS technology beyond the 16-nm node, and some of these parameters have been achieved. These parameters include low interfacial density of states; low electrical leakage currents; high-temperature (800–900°C) thermal stability for high-κ dielectrics/InGaAs heterostructures, where the amorphous oxide structure and atomically smooth and sharp interfaces are retained; and oxide scalability with a capacitance equivalent thickness of ≤1 nm. Interfacial chemical properties and band parameters, which are important for device design in the high κs/InGaAs, have been thoroughly studied. Representative enhancement-mode InGaAs MOSFETs are compared and correlated with the interfacial structures. Deposition methods and electrical characteristics of high-κ dielectrics on InGaA are discussed. The inversion channel InGaAs MOSFETs of 0.4–1.0 μm gate length have exhibited excellent device performance in terms of drain current and transconductance.
Compound Semiconductors for Low-Power p-Channel Field-Effect Transistors
Authors: Bennett Brian R. , Ancona Mario G. , Boos J. Brad 
Published: February 2011

AbstractResearch in n-channel field-effect transistors based upon III–V compound semiconductors has been very productive over the last 30 years, with successful applications in a variety of high-speed analog circuits. For digital applications, complementary circuits are desirable to minimize static power consumption. Hence, p-channel transistors are also needed. Unfortunately, hole mobilities are generally much lower than electron mobilities for III–V compounds. This article reviews the recent work to enhance hole mobilities in antimonide-based quantum wells. Epitaxial heterostructures have been grown with the channel material in 1–2% compressive strain. The strain modifies the valence band structure, resulting in hole mobilities as high as 1500 cm2/Vs. The next steps toward an ultra-low-power complementary metal oxide semiconductor technology will include development of a compatible insulator technology and integration of n- and p-channel transistors.
Meso- and Macroporous Ceramics by Phase Separation and Reactive Sintering Methods
Authors: Suzuki Yoshikazu , Morgan Peter E.D. 
Published: February 2011

AbstractControlled pore glasses are formed through selective etching of one phase of a spinodally decomposed borosilicate glass, an old technique that is the basis of the porous Vycor synthesis technique developed in the 1920s. This technique is receiving renewed attention as these glasses find new applications as substrates for biosensing, bioreactors, precise filtration, and chromatography. Analogous techniques are being applied to crystalline ceramics, such as directed cooling of ZrO2/MgO and MgAl2O4/Al2O3 eutectics to drive phase separation with the subsequent dissolution of one phase. Pyrolytic reactive sintering is a combination of the phase separation method and the reactive sintering method to obtain a 3D porous structure network. For example, dolomite (CaMg[CO3]2) and ZrO2 yield a uniformly porous CaZrO3/MgO composite that utilizes evolved CO2 as a “pore-forming agent.” This article gives an overview of recent developments on meso- and macroporous ceramics based on phase separation and reactive sintering technologies.
Modeling Amorphous Porous Materials and Confined Fluids
Authors: Gelb Lev D. 
Published: February 2011

AbstractMany of the porous materials used in laboratory and industrial processes do not have simple regular or crystalline structures. This greatly complicates efforts to characterize them and to understand and optimize their performance for particular applications. This review surveys recent efforts to use simulation and modeling to better understand the structure and performance of several classes of materials, including phase-separated glasses, sol-gel–derived materials, templated silica materials, and activated carbons. Approaches to modeling these materials fall generally into two classes: reconstructions, which generate models based on experimental measurements, and mimetic simulations, which attempt to model the preparation of the materials. While significant progress has been made in many respects, both reconstructive and mimetic transferred currently available are often computationally intensive and not easily transferable between different classes of materials. Finally, since gas adsorption is used widely as a characterization tool for amorphous porous materials and is often the focus of the materials' application, recent developments in simulation and theory appropriate to the study of capillary phenomena in amorphous porous materials are reviewed.
Electromechanics on the Nanometer Scale: Emerging Phenomena, Devices, and Applications
Authors: Kalinin Sergei V. , Setter Nava , Kholkin Andrei L. 
Published: February 2011

AbstractCoupling between mechanical and electrical phenomena is ubiquitous at the nano-and molecular scales, with examples ranging from piezoelectricity and flexoelectricity in perovskites to complex molecular transformations in redox active molecules and ion channels. This article delineates the field of nanoelectromechanics enabled by recent advances in scanning probe, indentation, and interferometric techniques and provides a unified outlook at a number of related topics, including membrane and surface flexoelectricity, local piezoelectricity in ferroelectrics and associated devices, and electromechanical molecular machines. It also summarizes experimental and theoretical challenges on the pathway to visualize, control, and manipulate electromechanical activity on the nanoscale and molecular levels.
Piezoresponse Force Microscopy: A Window into Electromechanical Behavior at the Nanoscale
Authors: Bonnell D.A. , Kalinin S.V. , Kholkin A.L. , Gruverman A. 
Published: February 2011

AbstractPiezoresponse force microscopy (PFM) is a powerful method widely used for nanoscale studies of the electromechanical coupling effect in various materials systems. Here, we review recent progress in this field that demonstrates great potential of PFM for the investigation of static and dynamic properties of ferroelectric domains, nanofabrication and lithography, local functional control, and structural imaging in a variety of inorganic and organic materials, including piezoelectrics, semiconductors, polymers, biomolecules, and biological systems. Future pathways for PFM application in high-density data storage, nanofabrication, and spectroscopy are discussed.
Membrane Electromechanics in Biology, with a Focus on Hearing
Authors: Sachs F. , Brownell W. E. , Petrov A. G. 
Published: February 2011

AbstractCells are ion conductive gels surrounded by a ∼5-nm-thick insulating membrane, and molecular ionic pumps in the membrane establish an internal potential of approximately −90 mV. This electrical energy store is used for high-speed communication in nerve and muscle and other cells. Nature also has used this electric field for high-speed motor activity, most notably in the ear, where transduction and detection can function as high as 120 kHz. In the ear, there are two sets of sensory cells: the “inner hair cells” that generate an electrical output to the nervous system and the more numerous “outer hair cells” that use electromotility to counteract viscosity and thus sharpen resonance to improve frequency resolution. Nature, in a remarkable exhibition of nanomechanics, has made out of soft, aqueous materials a microphone and high-speed decoder capable of functioning at 120 kHz, limited only by thermal noise. Both physics and biology are only now becoming aware of the material properties of biomembranes and their ability to perform work and sense the environment. We anticipate new examples of this biopiezoelectricity will be forthcoming.
Nanoionics Switching Devices: “Atomic Switches”
Authors: Hasegawa Tsuyoshi , Terabe Kazuya , Sakamoto Toshitsugu , Aono Masakazu 
Published: February 2011

AbstractNovel nanoionics devices, atomic switches, have been developed using a solid-electrochemical reaction to control the formation and annihilation of the metal filament between two electrodes. The switching operation can be achieved simply by the application of a bias voltage to precipitate metal atoms in a nanogap between the two electrodes or to dissolve them onto one of the electrodes. The small size of atomic switches enables rapid switching even though atomic motion is required. They also have several novel characteristics in that they are nonvolatile, consume less power, and have a simple structure and a low on-resistance. Logic gates and 1 kbit nonvolatile memory chips have been developed using atomic switches in order to demonstrate the possibilities for improving present-day electronic devices. Their characteristics also enable the fabrication of new types of electronic devices, such as high-performance programmable logic devices that may achieve a multitude of functions on a single chip.
Solid-State Materials for Clean Energy: Insights from Atomic-Scale Modeling
Authors: Saiful Islam M. , Slater Peter R. 
Published: February 2011

AbstractFundamental advances in solid-state ionics for energy conversion and storage are crucial in addressing the global challenge of cleaner energy sources. This review aims to demonstrate the valuable role that modern computational techniques now play in providing deeper fundamental insight into materials for solid oxide fuel cells and rechargeable lithium batteries. The scope of contemporary work is illustrated by studies on topical materials encompassing perovskite-type proton conductors, gallium oxides with tetrahedral moieties, apatite-type silicates, and lithium iron phosphates. Key fundamental properties are examined, including mechanisms of ion migration, dopant-defect association, and surface structures and crystal morphologies.
Exploiting New Opportunities in Materials Research by Remembering and Applying Old Lessons
Authors: Nix William D. 
Published: February 2011

AbstractRecalling some of the progress that has been made in understanding the mechanical properties of materials over the past 50 years or so reveals the importance of remembering and applying old lessons when addressing new opportunities in materials research. Often, the classical lessons of the past are especially useful as a guide for thinking about new problems. Such an approach to new problems is intimately connected to the creation of simple models that capture the essential features of the phenomena involved. Experience shows that, although such efforts might not pay off immediately, they come to be useful many years later when new problems are confronted. The merit of applying old lessons to new problems is described herein by using examples from the author's career in characterizing and understanding the mechanical properties of materials. It is hoped that these lessons are sufficiently general to be applied to other areas of materials research. Problems ranging from the high-temperature creep resistance of titanium aluminides, to the residual stresses in deposited thin films, to diffusive relaxation processes in thin films, to the size dependence of the strength of crystalline materials at the nanometer scale, all provide examples of how applying lessons of the past can help to understand new problems. An effort is also made to identify new, emerging problems in materials research where the application of the lessons of the past, together with new capabilities of the future, can come together to produce a fresh understanding of material behavior.
A Mnemonic Scheme for Thermodynamics
Authors: Zhao J.-C. 
Published: February 2011

AbstractA mnemonic scheme is presented to help recall the equations in classical thermodynamics that connect the four state variables (temperature, pressure, volume, and entropy) to the four thermodynamic potentials (internal energy, Helmholtz free energy, enthalpy, and Gibbs free energy). Max Born created a square to help recall the thermodynamic equations. The new scheme here separates the Max Born square into two squares, resulting in easier recalling of several sets of equations, including the Maxwell equations, without complicated rules to remember the positive or negative signs.
Nanostructured Organic–Inorganic Hybrid Solar Cells
Authors: McGehee Michael D. 
Published: February 2011

AbstractWhen light is absorbed in organic semiconductors, bound electron–hole pairs known as excitons are generated. The electrons and holes separate from each other at an interface between two semiconductors by electron transfer. It is advantageous to form well-ordered nanostructures so that all of the excitons can reach the interface between the two semiconductors and all of the charge carriers have a pathway to the appropriate electrode. This article discusses charge and exciton transport in organic semiconductors, as well as the opportunities for making highly efficient solar cells and for using carbon nanotubes to replace metal oxide electrodes.
Synthesis and Processing of Organic Materials in Supercritical Carbon Dioxide
Authors: McCluskey Georgia E. , Lee Jin-Kyun , Sha Jing , Ober Christopher K. , Watkins Scott E. , Holmes Andrew B. 
Published: February 2011

AbstractCarbon dioxide (CO2) is arguably the most high-profile molecule of recent times. Although much of its bad press comes from environmental concerns associated with greenhouse gas emissions, there exists the possibility to harness this abundant resource for application to the synthesis and processing of useful materials. This article describes a selection of recent successes in using supercritical carbon dioxide (scCO2) as a solvent for polymerizations. Further, the uses of compressed CO2 as a processing tool in the fabrication of materials for applications such as coatings and biomaterials are discussed. Finally, the application of scCO2 to photolithography is demonstrated, with particular focus on CO2 as a processing solvent for the patterning of organic electronic devices.
Atomistic Simulations of Dislocations in Confined Volumes
Authors: Derlet P.M. , Gumbsch P. , Hoagland R. , Li J. , McDowell D.L. , Van Swygenhoven H. , Wang J. 
Published: February 2011

AbstractInternal microstructural length scales play a fundamental role in the strength and ductility of a material. Grain boundaries in nanocrystalline structures and heterointerfaces in nanolaminates can restrict dislocation propagation and also act as a source for new dislocations, thereby affecting the detailed dynamics of dislocation-mediated plasticity. Atomistic simulation has played an important and complementary role to experiment in elucidating the nature of the dislocation/interface interaction, demonstrating a diversity of atomic-scale processes covering dislocation nucleation, propagation, absorption, and transmission at interfaces. This article reviews some atomistic simulation work that has made progress in this field and discusses possible strategies in overcoming the inherent time scale challenge of finite temperature molecular dynamics.
Recent Advances in Bulk Crystal Growth
Authors: Fornari Roberto , Roth Michael 
Published: February 2011

AbstractThe growth of high-quality single crystals remains a challenging endeavor of materials science. Crystals of suitable size (from fiber crystals with diameters of tens of micrometers up to crystalline ingots or blocks with volumes up to 1 m3) and perfection (free from precipitates, inclusions, and twins with good uniformity and low concentration of dislocations) are required for fundamental research and practical implementation in microelectronic circuits, electro-optic switches and modulators, solid-state lasers, light-emitting diodes, sensors, and many other devices. In this introductory article of this issue of MRS Bulletin, we describe the two main challenges of today's crystal growth, namely (1) the production of well-established crystalline materials with improved structural perfection and larger size at a lower cost and (2) the bulk growth of new categories of materials with extreme thermodynamic characteristics, such as a very high melting point, high melting dissociation pressure, incongruent phase diagram, and anisotropic segregation. The subsequent six articles provide examples of how the crystal growers took up these challenges, which led to new experimental approaches and technological advances.