Featured Research

from universities, journals, and other organizations

'Cloning' could make structurally pure nanotubes for nanoelectronics

Date:
November 15, 2012
Source:
National Institute of Standards and Technology (NIST)
Summary:
Researchers have demonstrated a technique for growing virtually pure samples of single-wall carbon nanotubes 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 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

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 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.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. Jia Liu, Chuan Wang, Xiaomin Tu, Bilu Liu, Liang Chen, Ming Zheng, Chongwu Zhou. Chirality-controlled synthesis of single-wall carbon nanotubes using vapour-phase epitaxy. Nature Communications, 2012; 3: 1199 DOI: 10.1038/ncomms2205

Cite This Page:

National Institute of Standards and Technology (NIST). "'Cloning' could make structurally pure nanotubes for nanoelectronics." ScienceDaily. ScienceDaily, 15 November 2012. <www.sciencedaily.com/releases/2012/11/121115133802.htm>.
National Institute of Standards and Technology (NIST). (2012, November 15). 'Cloning' could make structurally pure nanotubes for nanoelectronics. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2012/11/121115133802.htm
National Institute of Standards and Technology (NIST). "'Cloning' could make structurally pure nanotubes for nanoelectronics." ScienceDaily. www.sciencedaily.com/releases/2012/11/121115133802.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Newsy (July 28, 2014) Stanford University published its findings for a "pure" lithium ion battery that could have our everyday devices and electric cars running longer. Video provided by Newsy
Powered by NewsLook.com
The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Shipping Crates Get New 'lease' On Life

Shipping Crates Get New 'lease' On Life

Reuters - Business Video Online (July 25, 2014) Shipping containers have been piling up as America imports more than it exports. Some university students in Washington D.C. are set to get a first-hand lesson in recycling. Their housing is being built using refashioned shipping containers. Lily Jamali reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins