Featured Research

from universities, journals, and other organizations

Nanotubes can solder themselves, markedly improving device performance

Date:
November 25, 2013
Source:
University of Illinois at Urbana-Champaign
Summary:
Researchers have developed a way to heal gaps in wires too small for even the world's tiniest soldering iron. Junctions between nanotubes have high resistance, slowing down the current and creating hotspots. The researchers use these hot spots to trigger a local chemical reaction that deposits metal that nano-solders the junctions.

Nano-soldering: Self-healing nanotube junctions.
Credit: Image courtesy of University of Illinois at Urbana-Champaign

University of Illinois researchers have developed a way to heal gaps in wires too small for even the world's tiniest soldering iron.

Led by electrical and computer engineering professor Joseph Lyding and graduate student Jae Won Do, the Illinois team published its results in the journal Nano Letters.

Carbon nanotubes are like tiny hollow wires of carbon just 1 atom thick -- similar to graphene but cylindrical. Researchers have been exploring using them as transistors instead of traditional silicon, because carbon nanotubes are easier to transport onto alternate substrates, such as thin sheets of plastic, for low-cost flexible electronics or flat-panel displays.

Carbon nanotubes themselves are high-quality conductors, but creating single tubes suitable to serve as transistors is very difficult. Arrays of nanotubes are much easier to make, but the current has to hop through junctions from one nanotube to the next, slowing it down. In standard electrical wires, such junctions would be soldered, but how could the gaps be bridged on such a small scale?

"It occurred to me that these nanotube junctions will get hot when you pass current through them," said Lyding, "kind of like faulty wiring in a home can create hot spots. In our case, we use these hot spots to trigger a local chemical reaction that deposits metal that nano-solders the junctions."

Lyding's group teamed with Eric Pop, an adjunct professor of electrical and computer engineering, and John Rogers, Swanlund professor in materials science and engineering, experts on carbon nanotube synthesis and transfer, as well as chemistry professor Greg Girolami. Girolami is an expert in a process that uses gases to deposit metals on a surface, called chemical vapor deposition (CVD).

The nano-soldering process is simple and self-regulating. A carbon nanotube array is placed in a chamber pumped full of the metal-containing gas molecules. When a current passes through the transistor, the junctions heat because of resistance as electrons flow from one nanotube to the next. The molecules react to the heat, depositing the metal at the hot spots and effectively "soldering" the junctions. Then the resistance drops, as well as the temperature, so the reaction stops.

The nano-soldering takes only seconds and improves the device performance by an order of magnitude -- almost to the level of devices made from single nanotubes, but much easier to manufacture on a large scale.

"It would be easy to insert the CVD process in existing process flows," Lyding said. "CVD technology is commercially available off-the-shelf. People can fabricate these transistors with the ability to turn them on so that this process can be done. Then when it's finished they can finish the wiring and connect them into the circuits. Ultimately it would be a low-cost procedure."

Now, the group is working to refine the process.

"We think we can make it even better," Lyding said. "This is the prelude, we hope, but it's actually quite significant."

The National Science Foundation and the Office of Naval Research supported this work. Lyding and Rogers also are affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I.

Video: http://www.youtube.com/watch?v=fWl0XvdzvVU


Story Source:

The above story is based on materials provided by University of Illinois at Urbana-Champaign. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jae-Won Do, David Estrada, Xu Xie, Noel N. Chang, Justin Mallek, Gregory S. Girolami, John A. Rogers, Eric Pop, Joseph W. Lyding. Nanosoldering Carbon Nanotube Junctions by Local Chemical Vapor Deposition for Improved Device Performance. Nano Letters, 2013; 131114122724007 DOI: 10.1021/nl4026083

Cite This Page:

University of Illinois at Urbana-Champaign. "Nanotubes can solder themselves, markedly improving device performance." ScienceDaily. ScienceDaily, 25 November 2013. <www.sciencedaily.com/releases/2013/11/131125164820.htm>.
University of Illinois at Urbana-Champaign. (2013, November 25). Nanotubes can solder themselves, markedly improving device performance. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2013/11/131125164820.htm
University of Illinois at Urbana-Champaign. "Nanotubes can solder themselves, markedly improving device performance." ScienceDaily. www.sciencedaily.com/releases/2013/11/131125164820.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
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