Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



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

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Gene therapy relieves back pain, repairs damaged disc in mice: Study suggests nanocarriers loaded with DNA could replace opioids May 17th, 2024

Shedding light on perovskite hydrides using a new deposition technique: Researchers develop a methodology to grow single-crystal perovskite hydrides, enabling accurate hydride conductivity measurements May 17th, 2024

Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in cuprate superconductor May 17th, 2024

Laboratories

A battery’s hopping ions remember where they’ve been: Seen in atomic detail, the seemingly smooth flow of ions through a battery’s electrolyte is surprisingly complicated February 16th, 2024

NRL discovers two-dimensional waveguides February 16th, 2024

Catalytic combo converts CO2 to solid carbon nanofibers: Tandem electrocatalytic-thermocatalytic conversion could help offset emissions of potent greenhouse gas by locking carbon away in a useful material January 12th, 2024

Three-pronged approach discerns qualities of quantum spin liquids November 17th, 2023

Govt.-Legislation/Regulation/Funding/Policy

International research team uses wavefunction matching to solve quantum many-body problems: New approach makes calculations with realistic interactions possible May 17th, 2024

Aston University researcher receives £1 million grant to revolutionize miniature optical devices May 17th, 2024

NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024

Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024

Nanotubes/Buckyballs/Fullerenes/Nanorods/Nanostrings

Catalytic combo converts CO2 to solid carbon nanofibers: Tandem electrocatalytic-thermocatalytic conversion could help offset emissions of potent greenhouse gas by locking carbon away in a useful material January 12th, 2024

TU Delft researchers discover new ultra strong material for microchip sensors: A material that doesn't just rival the strength of diamonds and graphene, but boasts a yield strength 10 times greater than Kevlar, renowned for its use in bulletproof vests November 3rd, 2023

Tests find no free-standing nanotubes released from tire tread wear September 8th, 2023

Detection of bacteria and viruses with fluorescent nanotubes July 21st, 2023

Discoveries

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Diamond glitter: A play of colors with artificial DNA crystals May 17th, 2024

Finding quantum order in chaos May 17th, 2024

Advances in priming B cell immunity against HIV pave the way to future HIV vaccines, shows quartet of new studies May 17th, 2024

Announcements

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Diamond glitter: A play of colors with artificial DNA crystals May 17th, 2024

Finding quantum order in chaos May 17th, 2024

Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in cuprate superconductor May 17th, 2024

Research partnerships

Gene therapy relieves back pain, repairs damaged disc in mice: Study suggests nanocarriers loaded with DNA could replace opioids May 17th, 2024

Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024

Researchers’ approach may protect quantum computers from attacks March 8th, 2024

How surface roughness influences the adhesion of soft materials: Research team discovers universal mechanism that leads to adhesion hysteresis in soft materials March 8th, 2024

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