Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanotubes with 2 walls have singular qualities

16.04.2015

Rice University lab calculates unique electronic qualities of double-walled carbon nanotubes

Rice University researchers have determined that two walls are better than one when turning carbon nanotubes into materials like strong, conductive fibers or transistors.


Researchers at Rice University are working to determine the electronic properties of double-walled carbon nanotubes. In this example, the team analyzed a nanotube with two zigzag components. The individual nanotubes have band gaps and are semiconductors, but when combined, the band gaps overlap and make the double-walled a semimetal.

Credit: Illustration by Matías Soto/Rice University

Rice materials scientist Enrique Barrera and his colleagues used atomic-level models of double-walled nanotubes to see how they might be tuned for applications that require particular properties. They knew from others' work that double-walled nanotubes are stronger and stiffer than their single-walled cousins. But they found it may someday be possible to tune double-walled tubes for specific electronic properties by controlling their configuration, chiral angles and the distance between the walls.

The research reported in Nanotechnology was chosen as the journal's "publisher's pick" this month. The journal also published an interview with the study's lead author, Rice graduate student Matías Soto.

Carbon nanotubes, grown by various methods, come in two basic varieties: single-walled and multiwalled (those with two or more walls). But double-walled tubes hold a special place in the hierarchy because, the researchers wrote, they behave somewhat like single-walled tubes but are stronger and better able to survive extreme conditions.

The Rice team found there's even more to them when they started looking at how the inner and outer walls match up using tubes with zigzag chirality. Because the electrical properties of single-walled tubes depend on their chirality - the angles of their hexagonal arrangement of atoms - the researchers thought it would be interesting to learn more about those properties in double-walled tubes.

"We saw that the interwall interaction could affect the electronic properties of double-walled carbon nanotubes and decided to study this effect in a more systematic way using computational simulations," Soto said.

It turned out that both the distance between the walls -- as small as a fraction of a nanometer -- and the individual chirality of the tubes impact the double-walls' electrical properties. In addition, the researchers found the diameter of the tube -- especially the inner one, with its more pronounced curvature -- has a small but significant impact on the structure's semiconducting properties.

Breaking it down further, they determined that semiconducting nanotubes wrapped around metallic, highly conductive nanotubes could be the best candidates for tuning the band gap, the property that defines the value of a semiconductor.

"The most interesting thing we found was that when you combine a metallic with a semiconductor, the band gap depends on the distance between them," Soto said.

It's not yet possible to do so, but the ability to adjust the distance between walls may lead to nanotube transistors, he said.

Other nanotube configurations may be best for turning into macroscopic carbon nanotube conducting wires, particularly with metallic-metallic nanotubes, the researchers found.

###

Co-authors of the paper are Rice graduate students Travis Boyer and postdoctoral researchers Santoshkumar Biradar and Liehui Ge; Robert Vajtai, a senior faculty fellow at Rice; Alex Elías-Zúñiga, a professor at Tecnológico de Monterrey, Mexico; and Pulickel Ajayan, Rice's Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of materials science and nanoengineering and of chemistry. Barrera is a professor of materials science and nanoengineering.

Read the abstract at http://iopscience.iop.org/0957-4484/26/16/165201/article

This news release can be found online at http://news.rice.edu/2015/04/14/nanotubes-with-two-walls-have-singular-qualities-2/

Follow Rice News and Media Relations via Twitter @RiceUNews

Related Materials:

Lab talk post about the discovery: http://nanotechweb.org/cws/article/lab/60669

Enrique Barrera: https://msne.rice.edu/Content.aspx?id=105

Rice Department of Materials Science and NanoEngineering: https://msne.rice.edu

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,888 undergraduates and 2,610 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked among some of the top schools for best quality of life by the Princeton Review and for best value among private universities by Kiplinger's Personal Finance.

Media Contact

David Ruth
david@rice.edu
713-348-6327

 @RiceUNews

http://news.rice.edu 

David Ruth | EurekAlert!

More articles from Physics and Astronomy:

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
17.07.2018 | Forschungsverbund Berlin

nachricht Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>