Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > New theory explains electronic and thermal behavior of nanotubes

New theory explains electronic and thermal behavior of nanotubes

Champaign, IL | Posted on January 19, 2006

Researchers at the University of Illinois at Urbana-Champaign have made an important theoretical breakthrough in the understanding of energy dissipation and thermal breakdown in metallic carbon nanotubes. Their discovery will help move nanotube wires from laboratory to marketplace.

The remarkable electrical and mechanical properties of metallic carbon nanotubes make them promising candidates for interconnects in future nanoscale electronic devices. But, like tiny metal wires, nanotubes grow hotter as electrical current is increased. At some point, a nanotube will burn apart like an element in a blown fuse.

"Heat dissipation is a fundamental problem of electronic transport at the nanoscale," said Jean-Pierre Leburton, the Gregory Stillman Professor of Electrical and Computer Engineering at Illinois and co-author of a paper published in the Dec. 21 issue of the journal Physical Review Letters. "To fully utilize nanotubes as interconnects, we must characterize them and understand their behavior and operating limits."

Up to now, no coherent interpretation had been proposed that reconciled heat dissipation and electronic transport, and described thermal effects in metallic carbon nanotubes under electronic stress, said Leburton, who is also a researcher at the Beckman Institute for Advanced Science and Technology, at the Micro and Nanotechnology Laboratory and at the Frederick Seitz Materials Research Laboratory. "Our theoretical results not only reproduce experimental data for electronic transport, they also explain the odd behavior of thermal breakdown in these nanotubes."

For example, in both theory and experiment, the shorter the nanotube, the larger the current that can be carried before thermal breakdown occurs. Also, the longer the nanotube, the faster the rise in temperature as the threshold current for thermal heating is reduced.

In nanotubes, heat generated by electrical resistance creates atomic vibrations in the nanostructure, which causes more collisions with the charge carriers. The additional collisions generate more heat and more vibrations, followed by even more collisions in a vicious cycle that ends when the nanotube burns apart, breaking the circuit.

"Short nanotubes can carry more current before burning apart because they dissipate heat better than longer nanotubes," Leburton said. "Although the entire nanotube experiences resistance heating, the electrical contacts at each end act as heat sinks, which in short nanotubes are relatively close to one another, leading to efficient heat removal."

This phenomenon also explains why the highest temperature always occurs in the middle of the nanostructure, Leburton said, "which is the furthest point away from the two ends, and where burning occurs in longer nanotubes under electrical stress."

In another important finding, Leburton and his colleagues have revised the common belief that charge carriers go ballistic in short metallic nanotubes having high currents. Researchers had previously thought that charge carriers traveled from one terminal to the other like a rocket; that is, without experiencing collisions.

"We have shown that the high current level in short metallic nanotubes is not due to ballistic transport, but to reduced heating effects," Leburton said. "Owing to their large concentration, the charge carriers collide efficiently among themselves, which prevent them from going ballistic. Even in short nanostructures, the current level is determined by a balance between the attractive force of the external electric field and the frictional force caused by the nanotube thermal vibrations. The collisions among charge carriers help the energy transfer to the nanotubes which results in heat dissipation."

Co-authors of the paper are Leburton, electrical and computer engineering professor Andreas Cangellaris and graduate student Marcelo Kuroda.

The work was funded by the National Science Foundation and the Beckman Institute.

Editor's note: To reach Jean-Pierre Leburton, call 217-333-6813; jleburto@uiuc.edu

####
Contact:
James E. Kloeppel
Physical Sciences Editor
217-244-1073
kloeppel@uiuc.edu

Copyright © University of Illinois at Urbana-Champaign

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

Possible Futures

Doubling down on Schrödinger's cat May 27th, 2016

Harnessing solar and wind energy in one device could power the 'Internet of Things' May 26th, 2016

Thermal modification of wood and a complex study of its properties by magnetic resonance May 26th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Nanotubes/Buckyballs/Fullerenes

Programmable materials find strength in molecular repetition May 23rd, 2016

Nanotubes are beacons in cancer-imaging technique: Rice University researchers use spectral triangulation to pinpoint location of tumors May 21st, 2016

Unveiling the electron's motion in a carbon nanocoil: Development of a precise resistivity measurement system for quasi-one-dimensional nanomaterials using a focused ion beam May 16th, 2016

New research shows how silver could be the key to gold-standard flexible gadgets: Silver nanowires are an ideal material for current and future flexible touch-screen technologies May 13th, 2016

Nanoelectronics

Researchers demonstrate size quantization of Dirac fermions in graphene: Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices May 20th, 2016

Graphene: A quantum of current - When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene May 20th, 2016

New type of graphene-based transistor will increase the clock speed of processors: Scientists have developed a new type of graphene-based transistor and using modeling they have demonstrated that it has ultralow power consumption compared with other similar transistor devices May 19th, 2016

Self-healing, flexible electronic material restores functions after many breaks May 17th, 2016

Discoveries

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

PETA science group publishes a review on pulmonary effects of nanomaterials: Archives of Toxicology publishes a review of scientific studies on fibrotic potential of nanomaterials May 26th, 2016

Harnessing solar and wind energy in one device could power the 'Internet of Things' May 26th, 2016

Announcements

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Deep Space Industries and SFL selected to provide satellites for HawkEye 360’s Pathfinder mission: The privately-funded space-based global wireless signal monitoring system will be developed by Deep Space Industries and UTIAS Space Flight Laboratory May 26th, 2016

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




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic