Navigation Links
'Cloning' could make structurally pure nanotubes for nanoelectronics
Date:11/15/2012

Researchers from the University of Southern California (USC) and the National Institute of Standards and Technology (NIST) have demonstrated a technique for growing virtually pure samples of single-wall carbon nanotubes (SWCNTs) with identical structures, a process they liken to "cloning" the nanotubes.* If it can be suitably scaled up, their approach could solve an important materials problem in nanoelectronics: producing carbon nanotubes of a specific structure to order.

Single-wall carbon nanotubes are hollow cylinders of carbon atoms bound together in a hexagonal pattern, usually about a nanometer in diameter. One fascinating feature of nanotubes is that there are many ways to wrap the hexagon sheet into a cylinder, from perfectly even rows of hexagons that wrap around in a ring, to rows that wrap in spirals at various angles"chiralities," to be technical. Even more interesting, chirality is critical to the electronic properties of carbon nanotubes. Some structures are electrical conductorsessentially a nanoscale wireothers are semiconductors.

"Experts in the electronics industry believe that single-wall carbon nanotubes are a promising option for nanoelectronicssemiconductor devices beyond today's CMOS technology," says NIST materials scientist Ming Zheng, "But for that particular application, the structure is critically important. A fundamental issue in that field is how to make single-wall nanotubes with a defined structure."

The problem is that methods for manufacturing carbon nanotubes, which often use a metal catalyst to initiate growth, usually produce a mixture of many different chiralities or twistsalong with a lot of junk that's just soot. A lot of research has concentrated on schemes for "purifying" the batch to extract one particular kind of nanotube. And also you have to get rid of the catalyst.

The team led by Zheng and Professor Chongwu Zhou of USC took a different tack. NIST researchers had developed a technique for extracting nanotubes of a specific twist from a solution by using specially tailored DNA molecules that bind to one particular nanotube chirality.** The DNA trick is very selective, but unfortunately only works well with fairly short pieces of nanotube.

"That approach laid the foundation for this work," says Zheng. "We are using the short purified nanotubes to grow bigger structures of the same kind. We call it 'cloning', like cloning an organism from its DNA and a single cell, but in this case, we use a purified nanotube as a seed."

Small segments of nanotubes of identical chirality, extracted using the DNA technique, were put in a high-temperature reaction chamber at USC with methane gas, which breaks down in the heat to smaller carbon molecules that attach themselves to the ends of the nanotubes, gradually building them upand preserving their structural chirality. "A bit like building a skyscraper," Zheng observes, though in these early experiments, the tubes are laying on a substrate.

"I think the most important thing this work shows is that from a chemistry point of view, it's entirely possible to grow nanotubes without a catalyst, and even maintain control of the structure," says Zheng, "It's a different approach, to do the separation first to obtain the 'seeds' and then do the synthesis to grow the desired nanotubes."


'/>"/>

Contact: Michael Baum
michael.baum@nist.gov
301-975-2763
National Institute of Standards and Technology (NIST)
Source:Eurekalert  

Related biology technology :

1. Microfabrication breakthrough could set piezoelectric material applications in motion
2. Pitt discoveries in quantum physics could change face of technology
3. Nanoparticle electrode for batteries could make grid-scale power storage feasible
4. New magnetic-field-sensitive alloy could find use in novel micromechanical devices
5. Low-cost paper-based wireless sensor could help detect explosive devices
6. New method for enhancing thermal conductivity could cool computer chips, lasers and other devices
7. Discovery of a dark state could mean a brighter future for solar energy
8. Research could improve laser-manufacturing technique
9. Manipulating way bacteria talk could have practical applications, Texas A&M profs say
10. Honeycombs of magnets could lead to new type of computer processing
11. Quantum control protocols could lead to more accurate, larger scale quantum computations
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
'Cloning' could make structurally pure nanotubes for nanoelectronics
(Date:5/25/2016)... ... May 25, 2016 , ... Lajollacooks4u has become a rising ... been rated one of its top attractions. Fortune 500 companies, such as Illumina, ... a unique and intimate team-building experience. , Each event kicks off with an olive ...
(Date:5/25/2016)... ... May 25, 2016 , ... The American Medical ... Office of the National Coordinator for Health IT (ONC) outlining a measurement approach ... data were available when and where it was needed. The organization of health ...
(Date:5/25/2016)... ... May 25, 2016 , ... ... and Drug Administration (FDA) has granted the company’s orphan drug designation request covering ... orphan drug designation granted by the FDA. , Spinocerebellar ataxia is a ...
(Date:5/24/2016)... ... May 24, 2016 , ... Media Cybernetics, global image ... Cybernetics corporate branding reflects a results-driven revitalization for a company with a renewed ... components include a crisp, refreshed logo and a new web presence. , “I ...
Breaking Biology Technology:
(Date:5/9/2016)... DUBAI , UAE, May 9, 2016 ... choice when it comes to expanding freedom for high ... Even in today,s globally connected world, there ... online conferencing system could ever duplicate sealing your deal ... are obtaining second passports by taking advantage of citizenship ...
(Date:4/28/2016)... 28, 2016 First quarter 2016:   ... compared with the first quarter of 2015 The gross ... M (loss: 18.8) and the operating margin was 40% (-13) ... Cash flow from operations was SEK 249.9 M (21.2) , ... is unchanged, SEK 7,000-8,500 M. The operating margin for ...
(Date:4/19/2016)... UAE, April 20, 2016 The ... as a compact web-based "all-in-one" system solution for all ... fingerprint reader or the door interface with integration authorization ... access control systems. The minimal dimensions of the access ... into the building installations offer considerable freedom of design ...
Breaking Biology News(10 mins):