Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > 'Cloning' could make structurally pure nanotubes for nanoelectronics

Cloning nanotubes: In this computer model, small, pre-selected nanotube "seeds" (yellow) are grown to long nanotubes of the same twist or "chirality" in a high-temperature gas of small carbon compounds

Credit: Courtesy USC
Cloning nanotubes: In this computer model, small, pre-selected nanotube "seeds" (yellow) are grown to long nanotubes of the same twist or "chirality" in a high-temperature gas of small carbon compounds

Credit: Courtesy USC

Abstract:
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.

'Cloning' could make structurally pure nanotubes for nanoelectronics

Gaithersburg, MD | Posted on November 15th, 2012

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 conductors—essentially a nanoscale wire—others are semiconductors.

"Experts in the electronics industry believe that single-wall carbon nanotubes are a promising option for nanoelectronics—semiconductor 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 twists—along 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 up—and 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."

The research was funded in part by the Semiconductor Research Corporation's Focus Center Research Program, Functional Engineered Nano Architectonics, and the Office of Naval Research.

* J. Liu, C. Wang, X.Tu, B. Liu, L. Chen, M. Zheng and C. Zhou. Chirality-controlled synthesis of single-wall carbon nanotubes using vapor phase epitaxy. Nature Communications, 3, Article number: 1199. doi:10.1038/ncomms2205.

** See, for example, the Aug. 2, 2011, NIST news item, "Armchair Science: DNA Strands That Select Nanotubes Are First Step to a Practical 'Quantum Wire'" at www.nist.gov/public_affairs/tech-beat/tb20110802.cfm#dna.

####

For more information, please click here

Contacts:
Michael Baum

301-975-2763

Copyright © National Institute of Standards and Technology (NIST)

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Halas wins American Chemical Society Award in Colloid Chemistry: Rice University nanophotonics pioneer honored for colloid research September 18th, 2018

Leti & EFI Aim to Dramatically Improve Reliability & Speed of Low-Cost Electronic Devices for Autos: Project Will Extend Model Predictive Control Technique to Microcontrollers, Digital Signal Processors and Other Devices that Lack Powerful Computation Capabilities September 18th, 2018

Researchers managed to prevent the disappearing of quantum information September 14th, 2018

Tiny camera lens may help link quantum computers to network September 14th, 2018

Laboratories

Cannibalistic materials feed on themselves to grow new nanostructures September 1st, 2018

A Novel Graphene Quantum Dot Structure Takes the Cake August 24th, 2018

Virginia Tech researchers develop novel process to 3D print one of the strongest materials on Earth August 23rd, 2018

Connecting the (Nano) Dots: NIST Says Big-Picture Thinking Can Advance Nanoparticle Manufacturing August 22nd, 2018

Govt.-Legislation/Regulation/Funding/Policy

Researchers managed to prevent the disappearing of quantum information September 14th, 2018

New photonic chip promises more robust quantum computers September 14th, 2018

Could a demon help to create a quantum computer? Physicists implement a version of Maxwell's famous thought experiment for reducing entropy September 5th, 2018

Ultracold atoms used to verify 1963 prediction about 1D electrons: Rice University, University of Geneva study focuses on theory that's increasingly relevant to chipmakers September 5th, 2018

Nanotubes/Buckyballs/Fullerenes/Nanorods

Carbon nanodots do an ultrafine job with in vitro lung tissue: New experiments highlight the role of charge and size when it comes to carbon nanodots that mimic the effect of nanoscale pollution particles on the human lung. September 12th, 2018

Graphene nanotubes outperform ammonium salts and carbon black in PU applications September 11th, 2018

S, N co-doped carbon nanotube-encapsulated CoS2@Co: Efficient and stable catalysts for water splitting September 10th, 2018

Peering into private life of atomic clusters -- using the world's tiniest test tubes September 6th, 2018

Discoveries

Researchers managed to prevent the disappearing of quantum information September 14th, 2018

Tiny camera lens may help link quantum computers to network September 14th, 2018

New devices based on rust could reduce excess heat in computers: Physicists explore long-distance information transmission in antiferromagnetic iron oxide September 14th, 2018

New photonic chip promises more robust quantum computers September 14th, 2018

Announcements

Halas wins American Chemical Society Award in Colloid Chemistry: Rice University nanophotonics pioneer honored for colloid research September 18th, 2018

Leti & EFI Aim to Dramatically Improve Reliability & Speed of Low-Cost Electronic Devices for Autos: Project Will Extend Model Predictive Control Technique to Microcontrollers, Digital Signal Processors and Other Devices that Lack Powerful Computation Capabilities September 18th, 2018

New devices based on rust could reduce excess heat in computers: Physicists explore long-distance information transmission in antiferromagnetic iron oxide September 14th, 2018

New photonic chip promises more robust quantum computers September 14th, 2018

Research partnerships

Leti & EFI Aim to Dramatically Improve Reliability & Speed of Low-Cost Electronic Devices for Autos: Project Will Extend Model Predictive Control Technique to Microcontrollers, Digital Signal Processors and Other Devices that Lack Powerful Computation Capabilities September 18th, 2018

Researchers managed to prevent the disappearing of quantum information September 14th, 2018

Tiny camera lens may help link quantum computers to network September 14th, 2018

New photonic chip promises more robust quantum computers September 14th, 2018

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project