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Nanotechnology Spotlight

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Showing Spotlights 33 - 40 of 116 in category Graphene (newest first):

 

Nanotechnology research produces foldable graphene electronics on paper

foldable_graphene_electronicsIn contrast to flexible electronics, which rely on bendable substrates, truly foldable electronics require a foldable substrate with a very stable conductor that can withstand folding, i.e. an edge in the substrate at the point of the fold, which develops creases, and the deformation remains even after unfolding. That means that, in addition to a foldable substrate like paper, the conductor that is deposited on this substrate also needs to be foldable. Researchers have now demonstrated a fabrication process for foldable graphene circuits based on paper substrates.

Posted: Aug 22nd, 2013

Inkjet printing of graphene for flexible electronics

print_patternGraphene has a unique combination of properties that is ideal for next-generation electronics, including mechanical flexibility, high electrical conductivity, and chemical stability. Combine this with inkjet printing, already extensively demonstrated with conductive metal nanoparticle ink, and you get an inexpensive and scalable path for exploiting these properties in real-world technologies. Although liquid-phase graphene dispersions have been demonstrated, researchers are still struggling with sophisticated inkjet printing technologies that allow efficient and reliable mass production of high-quality graphene patterns for practical applications. Recent work has addressed these issues and proposes an approach to overcome these problems.

Posted: Aug 20th, 2013

Preserving the edge magnetism of graphene nanoribbons

graphene_edgeEdge magnetism is a unique property of graphene ribbons that has been predicted by theory, but not yet directly confirmed experimentally. If researchers want to utilize zigzag graphene nanoribbons (zGNRs) in spintronics, they first need to figure out a suitable termination group for zGNRs. The often used hydrogen atom termination is not a good choice since hydrogen terminated zGNRs can only be stabilized at extremely low hydrogen concentrations. In new work, researchers designed special boundaries for zGNRs that could become both stable and maintain the edge magnetism.

Posted: Jul 2nd, 2013

High-performance graphene transistor with high room-temperature mobility

graphene_transistorUtilization of graphene may help realize innovative low power replacements for III-V materials based high electron mobility transistors while extending operational frequencies closer to the THz regime for superior wireless communications, imaging, and other novel applications. Device architectures explored to date suffer a fundamental performance roadblock due to lack of compatible deposition techniques for nanoscale dielectrics required to efficiently modulate graphene transconductance while maintaining low gate capacitance-voltage product. In new work, researchers have shown that a double layer of graphene with structural transformation to a striped channel architecture can produce high field effect mobility at a very low operation voltage.

Posted: Jun 26th, 2013

Unusual behavior of graphene under irradiation: More damage - less noise

grapheneThe low-frequency 1/f noise is a ubiquitous phenomenon found everywhere from fluctuations of human heart rates to fluctuations of electrical currents in semiconductor devices. An acceptable level of flicker 1/f noise is one of the key metrics that each new material has to pass before it can be used for practical devices. Graphene has shown a great potential for applications in high-frequency communications, analog circuits and sensors. The envisioned applications require a low level of 1/f noise, which contributes to the phase-noise of communication systems and limits the sensor sensitivity. Now, researchers have discovered a unique feature of 1/f noise in graphene, which can help understand its microscopic origin and develop new techniques for noise reduction.

Posted: May 10th, 2013

Improving AFM probe performance with a coat of graphene

graphene-coated_AFM_probeMost of the research efforts on developing synthesis methods for graphene has focused on flat substrates. However, direct growth of graphene layers on prepatterned substrates has remained elusive. In new work, resarchers have grown graphene in prepatterned copper-coated substrates, and they apply this protocol for the fabrication of MEMS devices, in particular, atomic force microscope probes. This layer of graphene improves the functionality of the probes by making them conductive and more resistant to wear.

Posted: May 6th, 2013

Novel strategy to fabricate large-area graphene films and patterns

grapheneIntegration of graphene and its functional derivatives into three-dimensional macroscopic structures is an essential step to exploit the advanced properties of graphene sheets for practical applications, such as chemical filters and electrodes for energy storage devices. In new work, researchers in Singapore report a facile, scalable, and solution-processable strategy to synchronously reduce and assemble graphene oxide sheets on metal surface into large scale chemically converted graphene films under ambient conditions. Compared with other techniques currently used to prepare large-scale graphene film, this novel processing is low-temperature with scalable and high-throughput capability.

Posted: Apr 30th, 2013

Two-dimensional nanotechnology materials beyond graphene

2D_materialThe fascination with two-dimensional (2D) materials that has started with graphene has spurred researchers to look for other 2D structures like for instance metal carbides and nitrides. A new, very comprehensive review article takes a look at our current knowledge of 2D materials beyond graphene. The paper outlines the different chemical classes of 2D materials and discuss the various strategies to prepare single-layer, few-layer, and multilayer assembly materials in solution, on substrates, and on the wafer scale.

Posted: Apr 15th, 2013