Featured Research

from universities, journals, and other organizations

Nano-piezotronics: New Class Of Electronic Components Created By Bending Zinc Oxide Nanowires

Date:
March 2, 2007
Source:
Georgia Institute of Technology Research News
Summary:
Researchers have taken advantage of the unique coupled semiconducting and piezoelectric properties of zinc oxide nanowires to create a new class of electronic components and devices that could provide the foundation for a broad range of new applications.

A piezotronic diode is shown (a, c and e) in a sequence of scanning electron microscope images of bending a single zinc oxide nanowire between two probes. The graphs (b, d and f) show the corresponding current flow through the nanowire. (Credit: Image courtesy of Zhong Lin Wang)
Credit: Image courtesy of Zhong Lin Wang

Researchers have taken advantage of the unique coupled semiconducting and piezoelectric properties of zinc oxide nanowires to create a new class of electronic components and devices that could provide the foundation for a broad range of new applications.

Related Articles


So far, the researchers have demonstrated field-effect transistors, diodes, sensors -- and current-producing nanogenerators -- that operate by bending zinc oxide nanowires and nanobelts. The new components take advantage of the relationship between the mechanical and electronic coupled behavior of piezoelectric nanomaterials, a mechanism the researchers call "nano-piezotronics™."

"Nano-piezotronics utilizes the coupling of piezoelectric and semiconducting properties to fabricate novel electronic components," said Zhong Lin Wang, a Regents Professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. "These devices could provide the fundamental building blocks that would allow us to create a new area of electronics."

For example, in a nano-piezotronic transistor, bending a one-dimensional zinc oxide nanostructure alters the distribution of electrical charges, providing control over the current flowing through it. By measuring changes in current flow through them, piezotronic sensors can detect forces in the nano- or even pico-Newton range. Other piezotronic sensors can determine blood pressure within the body by measuring the current flowing through the nanostructures. And, an electrical connection made to one side of a bent zinc oxide nanostructure creates a piezotronic diode that limits current flow to one direction.

The nano-piezotronic mechanism takes advantage of the fundamental property of nanowires or nanobelts made from piezoelectric materials: bending the structures creates a charge separation -- positive on one side and negative on the other. The connection between bending and charge creation has also been used to create nanogenerators that produce measurable electrical currents when an array of zinc oxide nanowires is bent and then released

Development of a piezotronic gated diode based on zinc oxide nanowires was reported February 13 in the online advance issue of the journal Advanced Materials. Other nano-piezotronic components have been reported in the journals Nano Letters and Science. The research has been sponsored by the National Science Foundation (NSF), Defense Advanced Research Projects Agency (DARPA), the National Institutes of Health (NHI) and NASA.

"The future of nanotechnology research is in building integrated nanosystems from individual components," said Wang. "Piezotronic components based on zinc oxide nanowires and nanobelts have several important advantages that will help make such integrated nanosystems possible."

These advantages include:

  • Zinc oxide nanostructures can tolerate large amounts of deformation without damage, allowing their use in flexible electronics such folding power sources.
  • The large amount or deformation permits a large volume density of power output.
  • Zinc oxide materials are biocompatible, allowing their use in the body without toxic effects.
  • The flexible polymer substrate used in nanogenerators would allow implanted devices to conform to internal structures in the body.
  • Nanogenerators based on the structures could directly produce power for use in implantable systems.

In comparison to conventional electronic components, the nano-piezotronic devices operate much differently and exhibit unique characteristics.

In conventional field-effect transistors, for instance, an electrical potential -- called the gate voltage -- is applied to create an electrical field that controls the flow of current between the device's source and its drain. In the piezotronic transistors developed by Wang and his research team, the current flow is controlled by changing the conductance of the nanostructure by bending it between the source and drain electrodes. The bending produces a "gate" potential across the nanowire, and the resulting conductance is directly related to the degree of bending applied.

"The effect is to reduce the width of the channel to carry the current, so you can have a 10-fold difference in the conductivity before and after the bending," Wang explained.

Diodes, which restrict the flow of current to one direction, have also been created through nano-piezotronic mechanisms to take advantage of a potential barrier created at the interface between the electrode and the tensile (stretched) side of the nanowire by mechanical bending. The potential barrier created by the piezoelectric effect limits the follow of current to one direction.

Nanogenerators, which were announced in the April 14, 2006 issue of the journal Science, harvest energy from the environment around them, converting mechanical energy from body movement, muscle stretching, fluid flow or other sources into electricity. By producing current from the bending and releasing of zinc oxide nanowires, these devices could eliminate the need for batteries or other bulky sources for powering nanometer-scale systems.

Piezotronic nanosensors can measure nano-Newton (10 -9) forces by examining the shape of the structure under pressure. Implantable sensors based on the principle could continuously measure blood pressure inside the body and relay the information wirelessly to an external device similar to a watch, Wang said. The device could be powered by a nanogenerator harvesting energy from blood flow.

Other nanosensors can detect very low levels of specific compounds by measuring the current change created when molecules of the target are adsorbed to the nanostructure's surface. "Utilizing this kind of device, you could potentially sense a single molecule because the surface area-to-volume ratio is so high," Wang said.

In addition to Wang, the research team included J.H. Song, X.D. Wang, P.X. Gao, J.H. He, J. Zhou, N.S. Xu, L.J. Chen and J. Liu from Georgia Tech, the National Tsing Hua University in Taiwan and Sun Yat-Sen University in China.


Story Source:

The above story is based on materials provided by Georgia Institute of Technology Research News. Note: Materials may be edited for content and length.


Cite This Page:

Georgia Institute of Technology Research News. "Nano-piezotronics: New Class Of Electronic Components Created By Bending Zinc Oxide Nanowires." ScienceDaily. ScienceDaily, 2 March 2007. <www.sciencedaily.com/releases/2007/03/070301102731.htm>.
Georgia Institute of Technology Research News. (2007, March 2). Nano-piezotronics: New Class Of Electronic Components Created By Bending Zinc Oxide Nanowires. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2007/03/070301102731.htm
Georgia Institute of Technology Research News. "Nano-piezotronics: New Class Of Electronic Components Created By Bending Zinc Oxide Nanowires." ScienceDaily. www.sciencedaily.com/releases/2007/03/070301102731.htm (accessed October 24, 2014).

Share This



More Matter & Energy News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
Real-Life Transformer Robot Walks, Then Folds Into a Car

Real-Life Transformer Robot Walks, Then Folds Into a Car

Buzz60 (Oct. 24, 2014) Brave Robotics and Asratec teamed with original Transformers toy company Tomy to create a functional 5-foot-tall humanoid robot that can march and fold itself into a 3-foot-long sports car. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Police Testing New Gunfire Tracking Technology

Police Testing New Gunfire Tracking Technology

AP (Oct. 24, 2014) A California-based startup has designed new law enforcement technology that aims to automatically alert dispatch when an officer's gun is unholstered and fired. Two law enforcement agencies are currently testing the technology. (Oct. 24) 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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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