Featured Research

from universities, journals, and other organizations

Move over, silicon, there's a new circuit in town

Date:
June 17, 2014
Source:
University of Southern California
Summary:
When it comes to electronics, silicon will now have to share the spotlight. Scientists have now overcome a major issue in carbon nanotube technology by developing a flexible, energy-efficient hybrid circuit combining carbon nanotube thin film transistors with other thin film transistors. This hybrid could take the place of silicon as the traditional transistor material used in electronic chips, since carbon nanotubes are more transparent, flexible, and can be processed at a lower cost.

Hybrid CNT/IGZO circuits fabricated on a polyimide film laminated on a polydimethylsiloxane (PDMS) substrate.
Credit: USC Viterbi / Chongwu Zhou

When it comes to electronics, silicon will now have to share the spotlight. In a paper recently published in Nature Communications, researchers from the USC Viterbi School of Engineering describe how they have overcome a major issue in carbon nanotube technology by developing a flexible, energy-efficient hybrid circuit combining carbon nanotube thin film transistors with other thin film transistors. This hybrid could take the place of silicon as the traditional transistor material used in electronic chips, since carbon nanotubes are more transparent, flexible, and can be processed at a lower cost.

Electrical engineering professor Dr. Chongwu Zhou and USC Viterbi graduate students Haitian Chen, Yu Cao, and Jialu Zhang developed this energy-efficient circuit by integrating carbon nanotube (CNT) thin film transistors (TFT) with thin film transistors comprised of indium, gallium and zinc oxide (IGZO).

"I came up with this concept in January 2013," said Dr. Chongwu Zhou, professor in USC Viterbi's Ming Hsieh Department of Electrical Engineering. "Before then, we were working hard to try to turn carbon nanotubes into n-type transistors and then one day, the idea came to me. Instead of working so hard to force nanotubes to do something that they are not good for, why don't we just find another material which would be ideal for n-type transistors -- in this case, IGZO -- so we can achieve complementary circuits?"

Carbon nanotubes are so small that they can only be viewed through a scanning electron microscope. This hybridization of carbon nanotube thin films and IGZO thin films was achieved by combining their types, p-type and n-type, respectively, to create circuits that can operate complimentarily, reducing power loss and increasing efficiency. The inclusion of IGZO thin film transistors was necessary to provide power efficiency to increase battery life. If only carbon nanotubes had been used, then the circuits would not be power-efficient. By combining the two materials, their strengths have been joined and their weaknesses hidden.

Zhou likened the coupling of carbon nanotube TFTs and IGZO TFTs to the Chinese philosophy of yin and yang.

"It's like a perfect marriage," said Zhou. "We are very excited about this idea of hybrid integration and we believe there is a lot of potential for it."

The potential applications for this kind of integrated circuitry are numerous, including Organic Light Emitting Diodes (OLEDs), digital circuits, radio frequency identification (RFID) tags, sensors, wearable electronics, and flash memory devices. Even heads-up displays on vehicle dashboards could soon be a reality.

The new technology also has major medical implications. Currently, memory used in computers and phones is made with silicon substrates, the surface on which memory chips are built. To obtain medical information from a patient such as heart rate or brainwave data, stiff electrode objects are placed on several fixed locations on the patient's body. With this new hybridized circuit, however, electrodes could be placed all over the patient's body with just a single large but flexible object.

With this development, Zhou and his team have circumvented the difficulty of creating n-type carbon nanotube TFTs and p-type IGZO TFTs by creating a hybrid integration of p-type carbon nanotube TFTs and n-type IGZO TFTs and demonstrating a large-scale integration of circuits. As a proof of concept, they achieved a scale ring oscillator consisting of over 1,000 transistors. Up to this point, all carbon nanotube-based transistors had a maximum number of 200 transistors.

"We believe this is a technological breakthrough, as no one has done this before," said Haitian Chen, research assistant and electrical engineering PhD student at USC Viterbi. "This gives us further proof that we can make larger integrations so we can make more complicated circuits for computers and circuits."

The next step for Zhou and his team will be to build more complicated circuits using a CNT and IGZO hybrid that achieves more complicated functions and computations, as well as to build circuits on flexible substrates.

"The possibilities are endless, as digital circuits can be used in any electronics," Chen said. "One day we'll be able to print these circuits as easily as newspapers."

Zhou and Chen believe that carbon nanotube technology, including this new CNT-IGZO hybrid, will be commercialized in the next 5-10 years.

"I believe that this is just the beginning of creating hybrid integrated solutions," said Zhou. "We will see a lot of interesting work coming up."


Story Source:

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


Journal Reference:

  1. Haitian Chen, Yu Cao, Jialu Zhang, Chongwu Zhou. Large-scale complementary macroelectronics using hybrid integration of carbon nanotubes and IGZO thin-film transistors. Nature Communications, 2014; 5 DOI: 10.1038/ncomms5097

Cite This Page:

University of Southern California. "Move over, silicon, there's a new circuit in town." ScienceDaily. ScienceDaily, 17 June 2014. <www.sciencedaily.com/releases/2014/06/140617164332.htm>.
University of Southern California. (2014, June 17). Move over, silicon, there's a new circuit in town. ScienceDaily. Retrieved September 21, 2014 from www.sciencedaily.com/releases/2014/06/140617164332.htm
University of Southern California. "Move over, silicon, there's a new circuit in town." ScienceDaily. www.sciencedaily.com/releases/2014/06/140617164332.htm (accessed September 21, 2014).

Share This



More Matter & Energy News

Sunday, September 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

What This MIT Sensor Could Mean For The Future Of Robotics

What This MIT Sensor Could Mean For The Future Of Robotics

Newsy (Sep. 20, 2014) MIT researchers developed a light-based sensor that gives robots 100 times the sensitivity of a human finger, allowing for "unprecedented dexterity." Video provided by Newsy
Powered by NewsLook.com
MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
Powered by NewsLook.com
Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
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