Featured Research

from universities, journals, and other organizations

Duke Researchers Report Technique To Make More-Uniform "Buckytubes"

Date:
October 29, 2002
Source:
Duke University
Summary:
Duke University chemists report they have made a significant advance toward producing tiny hollow tubes of carbon atoms, called "nanotubes," with electronic properties reliable enough to use in molecular-sized circuits.

DURHAM, N.C. -- Duke University chemists report they have made a significant advance toward producing tiny hollow tubes of carbon atoms, called "nanotubes," with electronic properties reliable enough to use in molecular-sized circuits.

In a report posted Oct. 28, 2002, in the online version of the Journal of the American Chemical Society, the Duke group described a method to synthesize starting catalytic "nanocluster" particles of identical size that, in turn, can foster the growth of carbon nanotubes that vary in size far less than those produced previously.

"This is really a first step toward a big future," said Jie Liu, a Duke associate professor of chemistry and the group's leader, of the unprecedented nanotube uniformity they achieved using this process.

Sometimes called "buckytubes," carbon nanotubes' properties were first studied by Japanese researchers in the early 1990s. The nanotubes, measuring just billionths of a meter in diameter (nano means "billionths"), were found to be lightweight but exceptionally strong, with unusual electronic properties.

Depending upon their atomic arrangements, nanotubes can act like conducting metals or like semiconductors, Liu said.

Since microelectronic devices such as computer chips use both semiconductors and metals, researchers foresee nanotubes as the building blocks for even smaller electronic circuitry than the millionths-of-a-meter scale resolutions of today's microchips.

However, "controlling the electronic properties of the nanotubes is becoming the biggest bottleneck that limits the development of nanotube research," Liu said in an interview.

The control problem arises because those electronic properties vary with the way nanotubes' atoms are arranged. And how their atoms are arranged is directly tied to the nanotubes' diameters -- which, until the fabrication advance by Liu and his colleagues, could vary considerably.

In their journal report, Liu's graduate student Lei An, Liu and two University of North Carolina at Chapel Hill researchers describe a technique for growing nanotubes with diameters that varied by about 17 percent.

Using a technique called chemical vapor deposition, An and Liu sprouted the nanotubes from tiny catalyst particles called "nanoclusters." The researchers were able to make each of the nanoclusters completely identical.

"We have shown quite convincingly that by controlling the size of the starting catalyst we can control the diameter of the nanotubes," Liu said. "This is the first time that an identical catalyst has been used.

"The ultimate goal of the research is to produce multiple identical nanotubes using the same kind of catalyst particle," said Liu. "We're still pretty far from there. But it really represents a step forward to show that we have a collection of identical catalyst particles to start with."

The specific nanocluster made in An and Liu's Duke laboratory is one of a large family of catalytic molecules based on molybdenum oxide, he said.

Their nanoclusters contain 30 iron and 84 molybdenum atoms, plus carbon, hydrogen and oxygen atoms. While such clusters are not available from chemical supply houses, they are quite easy to make, Liu said. "And because it's so easy to make these clusters, it should also be easy to scale up to make large amounts of catalyst and large amounts of nanotubes," he said.

The researchers credited the use of a growth-regulating chemical called 3-aminopropyltriethoxysilane (APTES) for achieving more-uniform nanotubes diameters. The APTES kept the nanocluster particles confined to separate islands of discrete size as the nanotubes budded from a silicon dioxide surface.

If researchers can precisely control the nanotubes' diameters, said Liu, the researchers hope in the near future to make pure semiconducting and pure metallic nanotubes. "All the samples we are able to make now are a mix of metallic and semiconducting tubes," he said.

Carbon nanotubes are sometimes called buckytubes because of their structural similarities to carbon-based polyhedral molecules called buckminsterfullerenes, or "buckyballs." Pioneering work with buckyballs won a Nobel Prize for Richard Smalley's research group at Rice University, where Liu did postdoctoral work before coming to Duke.

The problems controlling nanotubes' electronic properties were recently noted in a news feature in the Oct. 10, 2002, issue of the journal Nature. "These difficulties may not be insurmountable," that article said, "but they have persuaded some scientists to turn their attention elsewehere."

In 2001, IBM researchers announced a "constructive destruction" method for separating semiconducting from metallic nanotubes by destroying the metallic ones with bursts of electricity.

An IBM news release said that other researchers have found semiconducting carbon nanotubes should be able to perform as well as silicon when configured into transistors. But nanotubes' molecular-scale sizes could result in computers that are smaller and operate faster using less power than today's silicon-based technology.


Story Source:

The above story is based on materials provided by Duke University. Note: Materials may be edited for content and length.


Cite This Page:

Duke University. "Duke Researchers Report Technique To Make More-Uniform "Buckytubes"." ScienceDaily. ScienceDaily, 29 October 2002. <www.sciencedaily.com/releases/2002/10/021029065429.htm>.
Duke University. (2002, October 29). Duke Researchers Report Technique To Make More-Uniform "Buckytubes". ScienceDaily. Retrieved August 2, 2014 from www.sciencedaily.com/releases/2002/10/021029065429.htm
Duke University. "Duke Researchers Report Technique To Make More-Uniform "Buckytubes"." ScienceDaily. www.sciencedaily.com/releases/2002/10/021029065429.htm (accessed August 2, 2014).

Share This




More Matter & Energy News

Saturday, August 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Tesla, Panasonic Ink Deal To Make Huge Battery 'Gigafactory'

Tesla, Panasonic Ink Deal To Make Huge Battery 'Gigafactory'

Newsy (July 31, 2014) The deal will help build a massive battery factory that Tesla says will produce 500,000 lithium batteries by 2020. Video provided by Newsy
Powered by NewsLook.com
Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
7 Ways to Use Toothpaste: Howdini Hacks

7 Ways to Use Toothpaste: Howdini Hacks

Howdini (July 30, 2014) Fresh breath and clean teeth are great, but have you ever thought, "my toothpaste could be doing more". Well, it can! Lots of things! Howdini has 7 new uses for this household staple. Video provided by Howdini
Powered by NewsLook.com
Smoked: 2015 Ducati Diavel Vs 2014 Chevy Corvette Stingray Drag Race

Smoked: 2015 Ducati Diavel Vs 2014 Chevy Corvette Stingray Drag Race

Cycle World (July 30, 2014) The Bonnier Motorcycle Group presents Smoked; a three part video series. In this episode the 2015 Ducati Diavel takes on the 2014 Chevy Corvette Stingray Video provided by Cycle World
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