Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Record Speed for Thin-Film Transistors Could Open Door for Flexible Electronics

Abstract:
A pair of University of Wisconsin-Madison researchers have developed a method of making flexible, thin-film transistors (TFTs) that are not only inexpensive to produce, but also capable of high speeds - even microwave frequency, impossible before now.

Record Speed for Thin-Film Transistors Could Open Door for Flexible Electronics

MADISON, WI | Posted on January 4th, 2007

Assistant professor of electrical and computer engineering Zhenqiang (Jack) Ma and graduate student Hao-Chih Yuan recently demonstrated flexible TFTs capable of operating at a world-record speed of 7.8 GHz.

TFTs are transistors that are currently widely used in electronics such as liquid crystal displays (LCD) and electronic and radio-frequency tags. For example, in an LCD screen, TFTs control individual pixels for high-quality images. TFTs made on flexible substrates could have a variety of applications, says Ma, including flexible and wearable electronics, flexible sensors, large-area surveillance radar, embedded signatures and more.

Until now, flexible TFTs have been relatively slow, operating in the 0.5 GHz range, says Yuan. This is fine for applications such as LCD, but not for applications such as military surveillance antennas that require high-performance but flexible circuitry for easy storage. "The application of current low-speed TFTs is very limited," says Ma. "Fast TFTs offer significant advantages in terms of power consumption and operation frequency, beside their flexibility and robustness against breakage."

Flexible TFTs are usually made of organic materials or amorphous or poly silicon, but the research team instead uses nanoscale-thin membranes of single-crystal silicon, which has greater electron mobility and greater speed. The membranes can be peeled off from the bulk silicon used for fabrication with an inexpensive, patent-pending method. But mobility is not enough to bring the TFTs up to speed, Ma says. Low-resistance electrode contacts are also important.

However, achieving this is challenging because the high temperatures needed to activate low-resistance contact connections melt the polymer substrates on which the transistors are fabricated. "That is the major obstacle to realizing the high speed operation of TFTs, regardless of the fact that high mobility has been already demonstrated in single-crystal silicon on flexible substrate," says Ma.

Ma and Yuan overcame this obstacle with an innovative technique. They made the transistors in "hot" and "cold" steps. First, they made the contact connectors on a bulk silicon substrate to achieve low resistance, and then transferred the single-crystal nanomembranes to the flexible substrate to continue fabrication. Ma and Yuan published a paper detailing this novel method in a recent issue of Applied Physics Letters.

Another factor in the new TFT's speed is that instead of the usual silicon dioxide, they made the gates of silicon monoxide, which carries the advantage of lower processing temperatures. "In addition, silicon monoxide has higher electric capacity and can be made thinner than the dioxide. As a result, the device speed becomes even faster," says Yuan.

The next step, says Ma, is developing even more advanced processing technologies and materials for even higher speed TFTs. He also hopes for the realization of potential applications, including an entire flexible radio-frequency system. "We opened numerous possibilities with this breakthrough," he says.

####

About University of Wisconsin
Founded in 1848, UW-Madison today has a total enrollment of over 41,000 students, 2,064 faculty,11,053 staff, 348,895 living alumni,and an annual operating budget of more than $1 billion.

For more information, please click here

Contacts:
Jack Ma, (608) 261-1095,
Liz Ahlberg, (608) 265-8592,

Copyright © University of Wisconsin

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

Nanoelectronics

Silicon chip with integrated laser: Light from a nanowire: Nanolaser for information technology February 12th, 2016

Electron's 1-D metallic surface state observed: A step for the prediction of electronic properties of extremely-fine metal nanowires in next-generation semiconductors February 9th, 2016

The iron stepping stones to better wearable tech without semiconductors February 8th, 2016

Spin dynamics in an atomically thin semi-conductor February 1st, 2016

Discoveries

'Lasers rewired': Scientists find a new way to make nanowire lasers: Berkeley Lab, UC Berkeley scientists adapt next-gen solar cell materials for a different purpose February 12th, 2016

Breaking cell barriers with retractable protein nanoneedles: Adapting a bacterial structure, Wyss Institute researchers develop protein actuators that can mechanically puncture cells February 12th, 2016

Replacement of Toxic Antibacterial Agents Possible by Biocompatible Polymeric Nanocomposites February 12th, 2016

Properties of Polymeric Nanofibers Optimized to Treat Damaged Body Tissues February 12th, 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