Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Techniques Pave Way for Carbon Nanotubes in Electronic Devices

08.11.2006
Many of the vaunted applications of carbon nanotubes require the ability to attach these super-tiny cylinders to electrically conductive surfaces, but to date researchers have only been successful in creating high-resistance interfaces between nanotubes and substrates.
Now a team from Rensselaer Polytechnic Institute reports two new techniques, each following a different approach, for placing carbon nanotube patterns on metal surfaces of just about any shape and size.

The results, which appear in separate papers from the November issue of Nature Nanotechnology and the Oct. 16 issue of Applied Physics Letters (APL), could help overcome some of the key hurdles to using carbon nanotubes in computer chips, displays, sensors, and many other electronic devices.

“Carbon nanotubes offer promising applications in fields ranging from electronics to biotechnology,” said Saikat Talapatra, a postdoctoral research associate with the Rensselaer Nanotechnology Center and lead author of the Nature Nanotechnology paper. But since many of these applications are based on the superior conductivity of carbon nanotubes, good contact between nanotubes and conducting metal components is essential.

Both of the newly developed techniques could bring the use of nanotubes as interconnects on computer chips closer to reality — a long-sought goal in the nanotechnology community. As chip makers seek to continually increase computing power, they are looking to shrink the dimensions of chip components to the nanometer scale, or about 1-100 billionths of a meter. Communication between components becomes increasingly difficult at this incredibly small scale, making carbon nanotubes a natural choice to replace metal wires, according to the researchers.

In the first technique — dubbed “floating catalyst chemical vapor deposition” — they heat a carbon-rich compound at extremely high temperatures until the material vaporizes. As the system cools, carbon deposits directly on the metal surface in the form of nanotube arrays. For this experiment, the team used surfaces made from Inconel, a nickel-based “super alloy” with good electrical conductivity. Until now this technique has only been used to grow nanotubes on substrates that are poor conductors of electricity.

There are many potential advantages to growing carbon nanotubes directly on metals with this simple, single-step process, according to Talapatra. Nanotubes attach to the surface with much greater strength; excellent electrical contact is established between the two materials; and nanotubes can be grown on surfaces of almost any shape and size, from curved sheets to long metal rods.

But chemical vapor deposition is a high-temperature process, which makes it incompatible with some sensitive electronic applications. “We have developed an alternate process of obtaining carbon nanotube arrays on any conducting substrate by contact printing methods,” said Ashavani Kumar, a postdoctoral research associate in materials science and engineering at Rensselaer and lead author of the APL paper.

In collaboration with Rajashree Baskaran, a staff research engineer in the Components Research Division at Intel Corporation, the team developed a procedure that mimics the way photographs are printed from a film negative. They first grow patterns of carbon nanotubes on silicon surfaces using chemical vapor deposition, and then the nanotubes are transferred to metal surfaces that are coated with solder — a metal alloy that is melted to join metallic surfaces together. The nanotubes stick in the solder, maintaining their original arrangement on the new surface.

And since solder has a low melting point, the process takes place at low temperature. “The contact printing process we have developed provides a potentially versatile method of incorporating carbon nanotubes in applications which cannot tolerate the typical high temperature of growth,” Baskaran said.

In addition to showing promise for interconnects in computer chips, carbon nanotubes also exhibit a physical property called “field emission.” When a voltage is applied, electrons are pulled out from the surface, which means that nanotubes could be combined with metals to produce high-resolution electronic displays, chemical sensors, and flash memory devices for computers.

The researchers also demonstrated that the chemical vapor deposition procedure can be used to make nanotube electrodes for “super capacitors” — devices that have unusually high energy densities when compared to common capacitors, which are used to store energy in electrical circuits. These are of particular interest in automotive applications for hybrid vehicles and as supplementary storage for battery electric vehicles, according to the researchers.

The research published in Nature Nanotechnology was funded by the National Science Foundation and the Interconnect Focus Center. The APL work was funded by Intel Corporation via a gift grant.

Both projects were performed under the guidance of Pulickel Ajayan, the Henry Burlage Professor of Materials Science and Engineering at Rensselaer and a world-renowned expert in fabricating nanotube-based materials. Other Rensselaer researchers involved with the project are: Robert Vajtai, Swastik Kar, Omkaram Nalamasu, Victor Pushparaj, Sunil Pal, Lijie Ci, Mancheri Shaijumon, and Sumanjeet Kaur.

Nanotechnology at Rensselaer

In September 2001, the National Science Foundation selected Rensselaer as one of the six original sites for a new Nanoscale Science and Engineering Center (NSEC). As part of the U.S. National Nanotechnology Initiative, the program is housed within the Rensselaer Nanotechnology Center and forms a partnership between Rensselaer, the University of Illinois at Urbana-Champaign, and Los Alamos National Laboratory. The mission of Rensselaer’s Center for Directed Assembly of Nanostructures is to integrate research, education, and technology dissemination, and to serve as a national resource for fundamental knowledge in directed assembly of nanostructures. The five other original NSECs are located at Harvard University, Columbia University, Cornell University, Northwestern University, and Rice University.

About Rensselaer

Rensselaer Polytechnic Institute, founded in 1824, is the nation’s oldest technological university. The university offers bachelor’s, master’s, and doctoral degrees in engineering, the sciences, information technology, architecture, management, and the humanities and social sciences. Institute programs serve undergraduates, graduate students, and working professionals around the world. Rensselaer faculty are known for pre-eminence in research conducted in a wide range of fields, with particular emphasis in biotechnology, nanotechnology, information technology, and the media arts and technology. The Institute is well known for its success in the transfer of technology from the laboratory to the marketplace so that new discoveries and inventions benefit human life, protect the environment, and strengthen economic development.

Jason Gorss | EurekAlert!
Further information:
http://www.rpi.edu

More articles from Physics and Astronomy:

nachricht New quantum phenomena in graphene superlattices
19.09.2017 | Graphene Flagship

nachricht Solar wind impacts on giant 'space hurricanes' may affect satellite safety
19.09.2017 | Embry-Riddle Aeronautical University

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: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

Im Focus: Artificial Enzymes for Hydrogen Conversion

Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.

Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

New quantum phenomena in graphene superlattices

19.09.2017 | Physics and Astronomy

A simple additive to improve film quality

19.09.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>