Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button

Home > Press > Triple-mode transistors show potential

Top left: A graphene transistor with source and drain electrodes; top right, a schematic for the triple-mode single-transistor graphene amplifier; and bottom, a graph showing the three distinct modes of operation. (Images: Mohanram Lab/Rice University)
Top left: A graphene transistor with source and drain electrodes; top right, a schematic for the triple-mode single-transistor graphene amplifier; and bottom, a graph showing the three distinct modes of operation. (Images: Mohanram Lab/Rice University)

Abstract:
Rice researchers introduce graphene-based amplifiers

Triple-mode transistors show potential

Houston, TX | Posted on October 13th, 2010

Rice University research that capitalizes on the wide-ranging capabilities of graphene could lead to circuit applications that are far more compact and versatile than what is now feasible with silicon-based technologies.

Triple-mode, single-transistor amplifiers based on graphene -- the one-atom-thick form of carbon that recently won its discoverers a Nobel Prize -- could become key components in future electronic circuits. The discovery by Rice researchers was reported this week in the online journal ACS Nano.

Graphene is very strong, nearly transparent and conducts electricity very well. But another key property is ambipolarity, graphene's ability to switch between using positive and negative carriers on the fly depending on the input signal. Traditional silicon transistors usually use one or the other type of carrier, which is determined during fabrication.

A three-terminal single-transistor amplifier made of graphene can be changed during operation to any of three modes at any time using carriers that are positive, negative or both, providing opportunities that are not possible with traditional single-transistor architectures, said Kartik Mohanram, an assistant professor of electrical and computer engineering at Rice. He collaborated on the research with Alexander Balandin, a professor of electrical engineering at the University of California, Riverside, and their students Xuebei Yang (at Rice) and Guanxiong Liu (at Riverside).

Mohanram likened the new transistor's abilities to that of a water tap. "Turn it on and the water flows," he said. "Turn it off and the water stops. That's what a traditional transistor does. It's a unipolar device -- it only opens and closes in one direction."

"But if you close a tap too much, it opens again and water flows. That's what ambipolarity is -- current can flow when you open the transistor in either direction about a point of minimum conduction."

That alone means a graphene transistor can be "n-type" (negative) or "p-type" (positive), depending on whether the carrier originates from the source or drain terminals (which are effectively interchangeable). A third function appears when the input from each carrier is equal: The transistor becomes a frequency multiplier. By combining the three modes, the Rice-Riverside team demonstrated such common signaling schemes as phase and frequency shift keying for wireless and audio applications.

"Our work, and that of others, that focuses on the applications of ambipolarity complements efforts to make a better transistor with graphene," Mohanram said. "It promises more functionality." The research demonstrated that a single graphene transistor could potentially replace many in a typical integrated circuit, he said. Graphene's superior material properties and relative compatibility with silicon-based manufacturing should allow for integration of such circuits in the future, he added.

Technological roadblocks need to be overcome, Mohanram said. Such fabrication steps as dielectric deposition and making contacts "wind up disturbing the lattice, scratching it and introducing defects. That immediately degrades its performance (limiting signal gain), so we have to exercise a lot of care in fabrication.

"But the technology will mature, since so many research groups are working hard to address these challenges," he said.

The National Science Foundation and the DARPA-Semiconductor Research Corporation's Focus Center Research Program supported the work.

Read the abstract at pubs.acs.org/doi/abs/10.1021/nn1021583.

####

For more information, please click here

Contacts:
David Ruth
713-348-6327


Mike Williams
713-348-6728

Copyright © Rice University

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

News and information

Making magnets flip like cats at room temperature: Heusler alloy NiMnSb could prove valuable as a new material for digital information processing and storage July 25th, 2016

An accelerated pipeline to open materials research: ORNL workflow system unites imaging, algorithms, and HPC to advance materials discovery and design July 24th, 2016

Russian physicists discover a new approach for building quantum computers: Physicists find a way of 'bundling together' multiple elements of a quantum computer July 24th, 2016

A 'smart dress' for oil-degrading bacteria July 24th, 2016

Govt.-Legislation/Regulation/Funding/Policy

An accelerated pipeline to open materials research: ORNL workflow system unites imaging, algorithms, and HPC to advance materials discovery and design July 24th, 2016

Quantum drag:University of Iowa physicist says current in one iron magnetic sheet can create quantized spin waves in another, separate sheet July 22nd, 2016

Weird quantum effects stretch across hundreds of miles July 21st, 2016

Scientists glimpse inner workings of atomically thin transistors July 21st, 2016

Possible Futures

Making magnets flip like cats at room temperature: Heusler alloy NiMnSb could prove valuable as a new material for digital information processing and storage July 25th, 2016

An accelerated pipeline to open materials research: ORNL workflow system unites imaging, algorithms, and HPC to advance materials discovery and design July 24th, 2016

Russian physicists discover a new approach for building quantum computers: Physicists find a way of 'bundling together' multiple elements of a quantum computer July 24th, 2016

A 'smart dress' for oil-degrading bacteria July 24th, 2016

Academic/Education

News from Quorum: The College of New Jersey use the Quorum Cryo-SEM preparation system in a project to study ice crystals in high altitude clouds July 19th, 2016

Leti and Korea Institute of Science and Technology to Explore Collaboration on Advanced Technologies for Digital Era July 14th, 2016

SUNY Poly Celebrates Its 10th Year Exhibiting at SEMICON West with Cutting Edge Developments in Integrated Photonics and Power Electronics July 8th, 2016

FEI and King Abdullah University of Science and Technology Establish New Electron Microscopy ‘Centre of Excellence’: Centre of Excellence involves materials and life sciences research and technical collaboration July 5th, 2016

Chip Technology

Making magnets flip like cats at room temperature: Heusler alloy NiMnSb could prove valuable as a new material for digital information processing and storage July 25th, 2016

An accelerated pipeline to open materials research: ORNL workflow system unites imaging, algorithms, and HPC to advance materials discovery and design July 24th, 2016

Russian physicists discover a new approach for building quantum computers: Physicists find a way of 'bundling together' multiple elements of a quantum computer July 24th, 2016

Quantum drag:University of Iowa physicist says current in one iron magnetic sheet can create quantized spin waves in another, separate sheet July 22nd, 2016

Nanotubes/Buckyballs/Fullerenes

Easier, faster, cheaper: A full-filling approach to making nanotubes of consistent quality: Approach opens a straightforward route for engineering the properties of single-wall carbon nanotubes July 19th, 2016

Sensing trouble: A new way to detect hidden damage in bridges, roads: University of Delaware engineers devise new method for monitoring structural health July 8th, 2016

Wireless, wearable toxic-gas detector: Inexpensive sensors could be worn by soldiers to detect hazardous chemical agents July 4th, 2016

Nanotubes' 'stuffing' as is: A scientist from the Lomonosov Moscow State University studied the types of carbon nanotubes' 'stuffing' June 2nd, 2016

Nanoelectronics

Making magnets flip like cats at room temperature: Heusler alloy NiMnSb could prove valuable as a new material for digital information processing and storage July 25th, 2016

Quantum drag:University of Iowa physicist says current in one iron magnetic sheet can create quantized spin waves in another, separate sheet July 22nd, 2016

Scientists glimpse inner workings of atomically thin transistors July 21st, 2016

'Green' electronic materials produced with synthetic biology July 16th, 2016

Announcements

Making magnets flip like cats at room temperature: Heusler alloy NiMnSb could prove valuable as a new material for digital information processing and storage July 25th, 2016

An accelerated pipeline to open materials research: ORNL workflow system unites imaging, algorithms, and HPC to advance materials discovery and design July 24th, 2016

Russian physicists discover a new approach for building quantum computers: Physicists find a way of 'bundling together' multiple elements of a quantum computer July 24th, 2016

A 'smart dress' for oil-degrading bacteria July 24th, 2016

Research partnerships

Quantum drag:University of Iowa physicist says current in one iron magnetic sheet can create quantized spin waves in another, separate sheet July 22nd, 2016

Rice's 'antenna-reactor' catalysts offer best of both worlds: Technology marries light-harvesting nanoantennas to high-reaction-rate catalysts July 18th, 2016

Researchers invent 'smart' thread that collects diagnostic data when sutured into tissue: Advances could pave way for new generation of implantable and wearable diagnostics July 18th, 2016

Leti and Korea Institute of Science and Technology to Explore Collaboration on Advanced Technologies for Digital Era July 14th, 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