X-ray sources based on carbon nanotube cold cathodes

Author Rémi Longtin    Category Publications     Tags ,

Scientists at the Swiss Federal Laboratories for Materials Science and Technology in Zurich, Switzerland, have built a functional X-ray tube using carbon nanotubes as electron sources. Carbon nanotube electron field-emission is well known effect and has been studied since the mid 1990s. Since then, several X-ray sources have been described in the scientific and technical literature.

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Benign joining of ultrafine grained aluminum alloys

Researchers at Empa in Zurich Switzerland have successfully joined nanostructured aerospace grade aluminum alloys with a minimal loss in mechanical properties using nanotechnology. The authors outline in a communication to Advanced Materials how it is possible to braze and solder benignly ultrafine grain aluminum. Nanostructured reactive foils were used as local heat sources. These foils rapidly release thermal energy directly at the interface between two materials leading to a metallurgical joint. The heat affected zone and the duration of heating are substantially limited, which in turn minimizes damage to the bulk. This is a first in the literature and is extremely relevant to several industries that have been struggling with the problem of joining temperature-sensitive materials while avoiding grain growth. This oven-less joining demonstration increases the attractiveness of nanostructured aluminum alloys as lightweight replacements material for conventional alloys.

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The geographic distribution of nanoscience and nanotechnology literature

Author Rémi Longtin    Category News, Publications     Tags ,

An essay in the journal Small (2011, 7, No. 20, 2836-C2839) discusses the growing footprint of nanoscience and nanotechnology on the global scientific landscape. The authors used query terms such as nano*, graphene* and polymer* in Web of Science by Thomson Reuters to generate search results from several key journals in the field such as ACS Nano and Nano Letters. The search results were subsequently analyzed in terms of scope, geographic distribution and footprint on the scientific literature. The essay’s main points are outlined below.

The percentage of the records returned by the search terms for each year dramatically increased from 20 % in 1991 to 80 % in 2010. Also, the term nano* was not sufficient to capture the full activity in these fields and tended to underestimate the literature, especially that of the 1990s. In terms of subject category, the increase in nanoscale studies has been of several-fold for the top 5 Web of Science categories, namely Physics, Materials Science, Chemistry (physical), Chemistry (multidisciplinary) and Nanoscience and Nanotechnology. The latter had the greatest increase from 18 to 70 % from 1997 to 2009.

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Designing diamond circuits for extreme environments

There is a new way to design computer chips and electronic circuitry for extreme environments: make them out of diamond. A team of electrical engineers at Vanderbilt University has developed all the basic components needed to create microelectronic devices out of thin films of nanodiamond. They have created diamond versions of transistors and, most recently, logical gates, which are a key element in computers.

“Diamond-based devices have the potential to operate at higher speeds and require less power than silicon-based devices,” Research Professor of Electrical Engineering Jimmy Davidson said. “Diamond is the most inert material known, so our devices are largely immune to radiation damage and can operate at much higher temperatures than those made from silicon.” Their design of a logical gate is described in the journal Electronics Letters.

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AIXTRON Black Magic systems

Author Patrice Guay    Category Industry     Tags

Based on plasma coupling technology, the “Black Magic” range of carbon nanotube and carbon fiber systems are highly flexible and reproducible. Turnkey 2”, 4” and 6” wafer-size systems, capable of single-walled and multi-walled carbon nanotube, nanofiber and graphene deposition, are available with many features for both research and production. Larger wafer-size systems are currently under development.

Manufacturer website: http://www.aixtron.com


Raman Spectroscopy as a Characterization Tool for Graphene

grapheneGraphene has attracted a great deal of attention because of its unique electronic properties that were praised by the Nobel Prize in 2010. Graphene holds promise to become a material of choice for the next generation of photovoltaic cells, field-effect devices (FED), flexible electronics, advanced composite materials, biosensors and advanced membranes. Raman spectroscopy is an easy and non-destructive method that played a critical role in characterization of graphene materials.

Materials Today in collaboration with Thermo Scientific are offering a short 45 minute webinar to introduce how Raman spectroscopy can help explore properties of graphene materials.
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RezQu: a scalable quantum computer

RezQu quantum chipRezQu is a family of devices and architecture for a scalable quantum computer based on superconducting phase qubits. RezQu is being developed by a team at the University of California, Santa Barbara led by John Martinis and Andrew Cleland. The team described their work at the American Physical Society meeting held on March 2011.

The 6cm-by-6cm chip holds nine quantum devices, among them four “quantum bits” that do the calculations. The team said further scaling up to 10 qubits should be possible this year. The team’s key innovation was to find a way to completely disconnect – or “decouple” – interactions between the elements of their quantum circuit. The delicate quantum states that they create must be manipulated, moved, and stored without destroying them. “It’s a problem I’ve been thinking about for three or four years now, how to turn off the interactions,” told John Martinis. “Now we’ve solved it, and that’s great – but there’s many other things we have to do.”

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“Carbon Nanotubes and Graphene” Symposium

EUROMAT2011A Symposium “Carbon Nanotubes and Graphene” will be organized at EUROMAT2011 in Montpellier (France), 12-15 September 2011. The symposium will especially focus on progress and hot topics related to large scale production/processing, applications and industrial issues. This specifically includes:

  • Synthesis and selection methods
  • Electronic, optical and mechanical properties of carbon nanotubes, graphene and related devices
  • Functionnalization, dispersion, processing
  • Metrology and standardization
  • Composites and materials science
  • Other applications and industrial issues

Integration of carbon nanotubes on CMOS wafers

CNT on CMOSCarbon nanotubes (CNT) – like other nanostructured materials – have high sensitivity to a large number of different gases and vapours which are important in areas as diverse as process monitoring in industry, environmental monitoring, agriculture, personal safety, medicine, or security screening. Gas sensors often operate by detecting the subtle changes that deposited gas molecules make in the way electricity moves through a surface layer. One advantage that carbon nanotubes offer for gas sensors, compared to metal oxide materials, is their fast response time and the fact that they react with gases at lower temperatures, sometimes even as low as room temperature.

In one promising application, researchers demonstrated the detection of specific odorous molecules with high resolution using a functionalized carbon nanotube based sensor. While the possibilities for CNT-based gas sensors are huge, the problem lies with the fabrication technologies, more specifically with a lack of technology for batch fabrication.

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Graphene discovery won scientists the 2010 Nobel prize in physics

Two University of Manchester scientists were awarded the 2010 Nobel Prize in physics for their pioneering research on graphene, a one-atom-thick film of carbon whose strength, flexibility and electrical conductivity have opened up new horizons for pure physics research as well as high-tech applications.

Andre Geim and his colleague (and former postdoctoral assistant) Konstantin Novoselov first produced graphene in 2004 by repeatedly peeling away graphite strips with adhesive tape to isolate a single atomic plane. They analyzed its strength, transparency, and conductive properties in a paper for Science the same year.

It’s a worthy Nobel, for the simple reason that graphene may be one of the most promising and versatile materials ever discovered. It could hold the key to everything from super small computers to high-capacity batteries. Graphene properties are attractive to materials scientists and electrical engineers for a whole host of reasons, not least of which is the fact that it might be possible to build circuits that are smaller and faster than what you can build in silicon.

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