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Nanotechnology Spotlight

Behind the buzz and beyond the hype:
Our Nanowerk-exclusive feature articles

Showing Spotlights 105 - 112 of 372 in category Fabrication Technologies and Devices (newest first):

 

Conformal printing of 3D electrically small antennas

antenna_printingElectrically small antennas (ESA) find use in a wide variety of communications platforms - e.g. mobile phones an other handheld devices, RFID, aerospace and defense systems - but their construction requires advances in printing as well as a robust antenna design so that their operating frequency, size, and system impedance could be easily varied. Researchers have now demonstrated the conformal printing of electrically small antennas on spherical shapes with a key performance metric (radiation quality factor or Q) that very closely approaches the fundamental limit dictated by physics. This fundamental design approach enables specification of both operating frequency and size, while achieving near-optimal bandwidth at several frequencies of interest for wireless communications.

Posted: Feb 3rd, 2011

Nanostructured scaffolds offer a promising route to repairing spinal cord injuries

spinal_cordSpinal cord injury in humans remains a devastating and incurable disorder. Rapid progress in tissue engineering, especially electrospinning techniques that lead to micro- and nanofibrous flexible tubular scaffolds for nerve cell regeneration, may lead to promising therapies for spinal cord injuries. have now demonstrated the repair of a chronically injured spinal cord by attempting to replace the fluid-filled cyst found in these lesions with a neuroprosthetics conducive to tissue reconstruction and axonal regeneration. They managed, for the first time, to obtain a consistent regeneration of the nervous tissue in chronicized injuries at the spinal cord by using a nanostructured composite scaffold with no cells in it.

Posted: Feb 2nd, 2011

Nanocomposite approach enhances the performance of thermoelectric materials

nanocompositeThermoelectric materials therefore hold great promise for turning waste heat back into useful power and are touted for use in hybrid cars, new and efficient refrigerators, and other cooling or heating applications. Thermoelectric devices are energy converters - they are based on the fact that when certain materials are heated, they generate a significant electrical voltage; conversely, when a voltage is applied to them, they become hotter on one side, and colder on the other. But they have one big drawback: they are very inefficient. Efficient thermoelectric materials need to be very good at conducting electricity, but not heat - and that's the problem; these materials are not efficient enough to be practical. In most materials, electrical and thermal conductivity go hand in hand. So researchers have to find ways of boosting the performance of thermoelectric materials by separating the two properties.

Posted: Jan 20th, 2011

Nanofabrication enables mass production of non-reflective polymer surfaces

A key hurdle in realizing high-efficiency, cost-effective solar energy technology is the low efficiency of current power cells. In order to achieve maximum efficiency when converting solar power into electricity, ideally you need a solar panel that can absorb nearly every single photon of light - across the entire spectrum of sunlight and regardless of the sun's position in the sky. One way to achieve suppression of sunlight's reflection over a broad spectral range is by using nanotextured surfaces that form a graded transition of the refractive index from air to the substrate. Researchers in Finland have now demonstrated a scalable, high-throughput fabrication method for such non-reflecting nanostructured surfaces.

Posted: Jan 5th, 2011

Hollow capsules expand graphene nano-toolbox

graphene_capsuleGraphene has attracted a huge amount of attention in recent years with its extraordinarily high electrical and thermal conductivities, mechanical, chemical properties, and large surface area. In order to meet the various demands for a variety of applications, preparation of desired structures of graphene sheets with controlled dimension and architecture are of significant importance. While research on flat graphene oxide structures has become quite common, there have been few reports on the preparation of hollow capsules of graphene through the nanosize, controlled assembly of graphene. Researchers in South Korea have now demonstrated the formation of graphene-based capsules through layer-by-layer (LbL) assembly of surface-functionalized reduced graphene oxide nanosheets of opposite charges onto polystyrene colloidal particles to produce multilayer thin films of graphene nanosheets.

Posted: Dec 14th, 2010

Novel, fast DNA nanopore detector features integrated tunneling electrodes

nanoporeResearchers worldwide are working on fast and low-cost strategies to sequence DNA, that is, to read off the content of our genome. Particularly promising for future genome sequencing are devices that measure single molecules. In this respect, the creation of nanochannels or nanopores in thin membranes has attracted much interest due to the potential to isolate and sense single DNA molecules while they translocate through the highly confined channels. Particularly interesting are techniques that can offer fast and low cost readout of long DNA molecules without the need of DNA labelling or amplification. In very interesting work performed at Imperial College London, researchers have now successfully developed a protocol for the fabrication of a solid state nanopore aligned to a tunneling junction.

Posted: Dec 13th, 2010

Nanoscopic patterning of nonplanar surfaces

nanopatterningProjection photolithography is mostly limited to flat surfaces. However, many emerging areas of micro- and nanotechnology applications, be it in optics, imaging, sensors or bioengineering, increasingly require the fabrication of microscopic and nanoscopic patterns on nonplanar surfaces. Contact printing and imprinting methods can cope with certain curved surfaces but appear to be restricted to those having a constant magnitude of curvature and a large radius of curvature relative to the arc length at least in one dimension. Researchers have now demonstrated that hexagonal noncontiguously packed (HNCP) colloidal crystals trapped at the air-water interface can be directly transferred onto solid substrates to give HNCP and distorted HNCP patterns. This bottom-up method uses self-assembled nanoparticle arrays and is not limited to flat surfaces at all.

Posted: Dec 6th, 2010

Dip-pen nanolithography as EBL alternative for fabricating graphene devices

nanolithographyDip-Pen Nanolithography (DPN) is a scanning probe lithography technique in which the tip of an atomic force microscope (AFM) is used to deliver molecules to a surface, allowing nanostructured surface patterning on scales of under 100 nm. This direct-write technique offers high-resolution patterning capabilities for a number of molecular and biomolecular 'inks' on a variety of substrates, such as metals, semiconductors, and monolayer functionalized surfaces. It's becoming a work-horse tool for the scientist interested in fabricating and studying soft- and hard-matter on the sub-100nm length scale. Using DPN for fabricating graphene devices has not been previously shown. Researchers at Stanford University have now evaluated DPN as an alternative to conventional electron-beam lithography (EBL) for tailoring such devices.

Posted: Dec 3rd, 2010