Report: Cell phones drive market for MEMS switches


MEMS switches and varicap products are finding their way into commercial products despite the economic downturn, thanks to increased interest from cell phone companies, according to a report from the research group Yole Développement.

Yole’s report highlights the companies it says are poised to be the next leading players and which applications will drive the MEMS switch and varicap sales in the 2007-2012 period.

Six players are currently commercializing or sampling products on the market (RadantMEMS, MEW, Advantest, XCOMwireless, MEMtronics, Wispry) and more than 20 additional products development projects have been listed in the report, according to Yole.

The report also focuses on RF MEMS switches for increasingly in-demand cell phone applications.

Patent granted to nanotech-based hazard suits

Miami-based Radiation Shield Technologies has been granted a US patent that secures its rights to the nanotech inside the company’s proprietary Demron protective material, according to the company.

Patent No. 7,476,889, “Radiation Detectable and Protective Articles” covers the company’s suits made to withstand chemical, biological, radiological and nuclear incidents.

Demron contains what the company calls an “advanced radiopaque nanopolymeric compound” fused between layers of fabric and manufactured into lightweight nuclear-radiation blocking garments including full-body suits, vests, blankets and medical X-ray vests and aprons.

Researchers control assembly of nanobristles

From the structure of DNA to nautical rope to distant spiral galaxies, helical forms are as abundant as they are useful in nature and manufacturing alike. Researchers at the Harvard School of Engineering and Applied Sciences (SEAS) have discovered a way to synthesize and control the formation of nanobristles into helical clusters, and have further demonstrated the fabrication of such highly ordered clusters over multiple scales and areas. The findings, reported in the January 9 issue of Science, have potential use in energy and information storage, photonics, adhesion, capture and release systems, and as an enhancement for the mixing and transport of particles.

Nanobristles hug a polystyrene sphere.
Click here to enlarge image

“We demonstrated a fascinating phenomenon: How a nanobristle immersed in an evaporating liquid self-assembles into an ordered array of helical bundles. This is akin to the way wet, curly hair clumps together and coils to form dreadlocks–but on a scale 1000 times smaller,” said lead author Joanna Aizenberg, Gordon McKay Professor of Materials Science at SEAS and the Susan S. and Kenneth L. Wallach Professor at the Radcliffe Institute for Advanced Study.

To achieve the “clumping” effect, the scientists used an evaporating liquid on a series of upright individual pillars arrayed like stiff threads on a needlepoint canvas. The resulting capillary forces caused the individual strands to deform and to adhere to one another like braided hair, forming nanobristles.

Further work involved further characterizing the geometry and material properties that favor the adhesive, coiled self-organization of bundles, which helped the team quantify the conditions for self-assembly into structures with uniform, periodic patterns, added the study’s other lead author, L. Mahadevan, Lola England de Valpine Professor of Applied Mathematics at SEAS.

By carefully designing the specific geometry of the bristle, the researchers were able to control the twist direction (or “handedness”) of the wrapping of two or more strands. More broadly, such work is expected to help further define the emerging science and engineering of functional self-assembly and pattern formation over large spatial scales.

Potential applications of the technique include the ability to store elastic energy and information embodied in adhesive patterns that can be created at will. This also has implications for photonics.

The findings also represent a critical step towards the development of an efficient adhesive or capture and release system for drug delivery and may be used to induce chiral flow patterns to enhance the mixing and transport of various particles at the micron- and submicron scale.

Bayer building big plant to churn out nanotubes

Bayer MaterialScience says it will invest about $29M to build a new facility in Germany that could churn out up to 200 tons of carbon nanotubes a year, making it the largest nanotube factory in the world, targeting a market projected to grow 25% annually to $2B over the next decade.

In December, the US Environmental Protection Agency gave Bayer MaterialScience regulatory approval to sell its multiwall carbon nanotubes–what it calls Baytubes–in the United States. The approval covered Baytubes C 150 P and HP grades, produced in a plant in Laufenburg, Germany with an annual capacity of 60 metric tons.

Baytubes can be added to polymer matrices or metal systems as a modifier or filler to improve their mechanical strength and/or antistatic properties, and are already used in epoxy, thermoplastic and coating systems, according to the company.

Smallest quantum dots bring real world applications closer

Single-atom quantum dots created by researchers at Canada’s National Institute for Nanotechnology and the University of Alberta make possible a new level of control over individual electrons, a development that brings quantum dot-based devices within reach. Composed of a single atom of silicon and measuring less than one nanometer in diameter, these are the smallest quantum dots ever created.

Quantum dots have extraordinary electronic properties that allow controlled interactions among electrons to be put to use to do computations. Until now, they have been usable only at impractically low temperatures, but the new atom-sized quantum dots perform at room temperature.

Four atomic quantum dots are coupled to form a “cell” for containing electrons. The cell is filled with just two electrons. Control charges are placed along a diagonal to direct the two electrons to reside at just two of the four quantum dots comprising the cell. This new level of control of electrons points to new computation schemes that require extremely low power to operate. Such a device is expected to require about 1,000× less power and will be about 1,000× smaller than today’s transistors. (Credit: Robert A. Wolkow)
Click here to enlarge image

Quantum dots have previously ranged in size from 2-10nm in diameter. While typically composed of several thousand atoms, all the atoms pool their electrons as if there is only one atomic nucleus at the center. That property enables numerous revolutionary schemes for electronic devices.

The single-atom quantum dots have also demonstrated another advantage–significant control over individual electrons by using very little energy. Research project leader Robert A. Wolkow sees this low energy control as the key to quantum dot application in entirely new forms of silicon-based electronic devices, such as ultralow-power computers. “The capacity to compose these quantum dots on silicon, the most established electronic material, and to achieve control over electron placement among dots at room temperature puts new kinds of extremely low energy computation devices within reach,” he stated.

Results of the work were published in the Jan. 30 edition of Physical Review Letters.

Nanotech-based catalyst paves way for ethanol fuel cells

Scientists at the US Department of Energy’s (DOE) Brookhaven National Laboratory, in collaboration with researchers from the University of Delaware and Yeshiva University, have developed a new nanotech-based catalyst that could make ethanol-powered fuel cells feasible. The highly efficient catalyst performs two crucial, and previously unreachable steps needed to oxidize ethanol and produce clean energy in fuel cell reactions. Their results are published online in the January 25 edition of Nature Materials.

Hydrogen fuel cells convert hydrogen and oxygen into water and, as part of the process, produce electricity. However, efficient production, storage, and transport of hydrogen for fuel cell use are not easily achieved. As an alternative, researchers are studying the incorporation of hydrogen-rich compounds–for example, the use of liquid ethanol in a system called a “direct ethanol fuel cell.”

“Ethanol is one of the most ideal reactants for fuel cells,” explained Brookhaven chemist Radoslav Adzic, in a statement. “It’s easy to produce, renewable, nontoxic, relatively easy to transport, and it has a high energy density. In addition, with some alterations, we could reuse the infrastructure that’s currently in place to store and distribute gasoline.”

A major hurdle to the commercial use of direct ethanol fuel cells is the molecule’s slow, inefficient oxidation, which breaks the compound into hydrogen ions and electrons that are needed to generate electricity. Specifically, scientists have been unable to find a catalyst capable of breaking the bonds between ethanol’s carbon atoms.

Now, scientists have found an electrocatalyst made of platinum and rhodium atoms on carbon-supported tin dioxide nanoparticles, capable of breaking carbon bonds at room temperature. Also, carbon dioxide is the main reaction product; other catalysts produce acetalhyde and acetic acid, which make them unsuitable for power generation.

Model of a ternary electrocatalyst for ethanol oxidation consisting of platinum-rhodium clusters on a surface of tin dioxide. This catalyst can split the carbon-carbon bond and oxidize ethanol to carbon dioxide within fuel cells.
Click here to enlarge image

“The ability to split the carbon-carbon bond and generate CO2 at room temperature is a completely new feature of catalysis,” Adzic said. “There are no other catalysts that can achieve this at practical potentials.”

The researchers predict that the high activity of their ternary catalyst results from the synergy between all three constituents (platinum, rhodium, and tin dioxide), knowledge that could be applied to other alternative energy applications.

“These findings can open new possibilities of research not only for electrocatalysts and fuel cells ,but also for many other catalytic processes,” Adzic said. Next step is to test the new catalyst in a real fuel cell in order to observe its unique characteristics first-hand.

ISO releases new standards for nanomaterials

The International Organization for Standardization has published new health and safety practices in occupational settings to nanotechnologies.

The report is based on current information about nanotechnologies, including characterization, health effects, exposure assessments, and control practices, ISO announced in a news release.

Broadly applicable across a range of nanomaterials and applications, the report provides advice for companies, researchers, workers and other people to prevent adverse health and safety consequences during the production, handling, use and disposal of manufactured nanomaterials.

“The introduction of new engineered nanomaterials into the workplace raises questions concerning occupational safety and health that should be addressed, as appropriate, by international standards, said Peter Hatto, chair of ISO technical committee that handles nanomaterials.

The report will be revised and updated and new safety standards will be developed as knowledge increases and experience is gained in the course of technological advance.

A super-sensitive gas sensor built with nanotubes

Researchers at the National Institute of Standards and Technology (NIST) have devised a new method for creating gas detectors so sensitive that some day they may be able to register tiny emissions from a single cell. Based on metal oxide nanotubes, the new sensors are a 100-1000× more sensitive than current devices based on thin films and are able to act as multiple sensors simultaneously.

Gas sensors often work by detecting changes made by gas molecules in electrical movement through a surface area. More surface area means more sensor sensitivity–and carbon nanotubes are almost all surface. Fabricating such a nanotube-based device is challenging, though, due to the nature of conventional technique: random scattering of nanotubes with electrical contacts either preformed or layered on, which makes it hard to determine precisely where reactions are happening (prevents multiple simultaneous tests), and no way to ensure the gas is reacting with the interior of a nanotube.

A schematic diagram (not to scale) of the preparation and application of a nanotube gas sensor based on tungsten oxide deposited on a substrate of nanoporous aluminum oxide. Perforated with millions of nanoscale holes, the aluminum oxide sheet served as a template or mold for the creation of the nanotubes. The sheet was dipped in a solution of tungsten ions, allowed to dry, and sintered four times (a baking process characterized by incremental temperature increases used to ensure that a coating will stick), building up a thin film of tungsten oxide on the walls of the pores. (Source: NIST)
Click here to enlarge image

In the NIST group’s process, a sheet of aluminum oxide about the thickness of a human hair is perforated with millions of holes about 200nm wide. With the nanosized pores serving as a mold, the researchers dipped the sheet in a solution of tungsten ions, coating the interior of the pores and casting the nanotubes in place. After the nanotubes were formed, the team deposited thin layers of gold on the top and bottom of the aluminum oxide membrane to act as electrical contacts.

The sensor’s high sensitivity derives from its design, which ensures that any sensor response is the result of the gas interacting with the interior of the nanotube. The researchers also note that this same technique can easily be adapted to form nanotubes of other semiconductors and metal oxides so long as the ends of the nanotubes remain open.

The work was published in Nov. 2008 by Sensors and Actuators B: Chemical.

Duke team creates semiconducting nanotubes

After announcing last April a method for growing exceptionally long, straight, numerous and well-aligned carbon cylinders only a few atoms thick, a Duke University-led team of chemists has now modified that process to create exclusively semiconducting versions of these single-walled carbon nanotubes.

The achievement paves the way for manufacturing reliable electronic nanocircuits at the ultra-small billionths of a meter scale, stated Jie Liu, Duke’s Jerry G. and Patricia Crawford Hubbard Professor of Chemistry, who headed the effort and has filed for a patent on the method. “I think it’s the holy grail for the field,” he said. “Every piece is now there, including the control of location, orientation and electronic properties all together. We are positioned to make large numbers of electronic devices such as high-current field-effect transistors and sensors.”

A report on their achievement, co-authored by Liu and a team of collaborators from his Duke laboratory and Peking University in China, was published Jan 20, 2009 in the research journal Nano Letters.

Battelle creates nanotech coating to fight rust

Researchers at Battelle have come up with a nanotech-based smart coating that can reveal where corrosion is forming on metal before it’s seen with the naked eye.

Ramanathan Lalgudi, a principal research scientist, and Barry McGraw, a program manager, were attaching groups of chemicals on the surface of nanomaterials and studying their effectiveness towards the environment–then thought to use the same technical approach to detect corrosion. Their creation: a smart coating derived from the functional nanomaterial that could be applied between a primer and topcoat and fluoresces once a corrosion product is generated from the metal. The metal used in their work is aluminum, but they say the chemistry can be tweaked for other metals. Lalgudi said the smart coating could even be married to a primer or integrated with a scanning device.

Battelle has a provisional patent for the IP and is seeking partners to push toward commercialization, seen as two or three years away.

Repairing metal before it is demonstrably compromised could save huge amounts of time, energy, materials, and money. Case in point: the US Department of Defense estimates that corrosion of its equipment costs $10B-$20B per year.

Mazda3 improves nanocatalyst tech

Mazda Motor Corp. says it is applying a new single-nanocatalyst technology in automobile catalytic converters to significantly reduce the amount of precious metals used and effectively purifies vehicle exhaust gases. The product will first be introduced in the new Mazda3 model (known as the Mazda Axela in Japan) that will launch globally this year.

With the single-nanocatalyst, the underfloor catalytic converter in the all-new Mazda3 requires only 0.15g/L of precious metals, ~70% less than the 0.55g/L required in the previous model. Additionally, the Mazda3 qualifies as a super ultralow-emissions vehicle (SU-LEV) in Japan by achieving exhaust emissions =75% cleaner than the government’s 2005 regulations.

Mazda’s new catalyst method features single-nanosized (<5nm-dia.) precious metal particles embedded in fixed positions, so there is no agglomeration of the particles and the amount of rare metals used can be significantly reduced. Moreover, the new catalyst material will enable very efficient purification with minimal deterioration over time even under the harshest operating conditions.
Click here to enlarge image

Automotive catalysts consist of a base material coated with precious metal particles which promote chemical reactions that purify exhaust gases. In conventional catalysts, exposure to hot exhaust gases causes these particles to agglomerate into larger clumps, which reduces their effective surface area and catalytic activity; more precious metals must be added to counteract this and maintain purification performance.