Featured Research

from universities, journals, and other organizations

What can happen when graphene meets a semiconductor

Date:
November 21, 2013
Source:
University of Wisconsin - Milwaukee
Summary:
A new study has found that intrinsic ripples form on a sheet of graphene when it is placed on top of a semiconductor. The ripples further change the Schottky barrier height, affecting electron transport.

UWM doctoral student Shivani Rajput, first author on the paper, shows a reconstructed image of graphene with the ripples clearly visible. Two postdoctoral researchers also worked on the project: Yaoyi Li (left) and Mingxing Chen.
Credit: Troye Fox

For all the promise of graphene as a material for next-generation electronics and quantum computing, scientists still don't know enough about this high-performance conductor to effectively control an electric current.

Related Articles


Graphene, a one-atom-thick layer of carbon, conducts electricity so efficiently that the electrons are difficult to control. And control will be necessary before this wonder material can be used to make nanoscale transistors or other devices.

A new study by a research group at the University of Wisconsin-Milwaukee (UWM) will help. The group has identified new characteristics of electron transport in a two-dimensional sheet of graphene layered on top of a semiconductor.

The researchers demonstrated that when electrons are rerouted at the interface of the graphene and its semiconducting substrate, they encounter what's known as a Schottky barrier. If it's deep enough, electrons don't pass, unless rectified by applying an electric field -- a promising mechanism for turning a graphene-based device on and off.

The group also found, however, another feature of graphene that affects the height of the barrier. Intrinsic ripples form on graphene when it is placed on top of a semiconductor.

The research group, led by Lian Li and Michael Weinert, UWM professors of physics, and Li's graduate student Shivani Rajput, conducted their experiment with the semiconductor silicon carbide. The results were published in the Nov. 21 issue of Nature Communications.

The ripples are analogous to the waviness of a sheet of paper that has been wetted and then dried. Except in this case, notes Weinert, the thickness of the sheet is less than one nanometer (a billionth of a meter).

"Our study says that ripples affect the barrier height and even if there's a small variation in it, the results will be a large change in the electron transport," says Li.

The barrier needs to be the same height across the whole sheet in order to ensure that the current is either on or off, he adds.

"This is a cautionary tale," says Weinert, whose calculations provided the theoretical analysis. "If you're going to use graphene for electronics, you will encounter this phenomenon that you will have to engineer around."

With multiple conditions affecting the barrier, more work is necessary to determine which semiconductors would be best suited to use for engineering a transistor with graphene.

The work also presents opportunity. The ability to control the conditions impacting the barrier will allow conduction in three dimensions, rather than along a simple plane. This 3D conduction will be necessary for scientists to create more complicated nano-devices, says Weinert.


Story Source:

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


Journal Reference:

  1. S. Rajput, M.X. Chen, Y. Liu, Y.Y. Li, M. Weinert, L. Li. Spatial fluctuations in barrier height at the graphene–silicon carbide Schottky junction. Nature Communications, 2013; 4 DOI: 10.1038/ncomms3752

Cite This Page:

University of Wisconsin - Milwaukee. "What can happen when graphene meets a semiconductor." ScienceDaily. ScienceDaily, 21 November 2013. <www.sciencedaily.com/releases/2013/11/131121142353.htm>.
University of Wisconsin - Milwaukee. (2013, November 21). What can happen when graphene meets a semiconductor. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2013/11/131121142353.htm
University of Wisconsin - Milwaukee. "What can happen when graphene meets a semiconductor." ScienceDaily. www.sciencedaily.com/releases/2013/11/131121142353.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Building Google Into Cars

Building Google Into Cars

Reuters - Business Video Online (Dec. 19, 2014) Google's next Android version could become the standard that'll power your vehicle's entertainment and navigation features, Reuters has learned. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
AP Review: Nikon D750 and GoPro Hero 4

AP Review: Nikon D750 and GoPro Hero 4

AP (Dec. 19, 2014) What to buy an experienced photographer or video shooter? There is some strong gear on the market from Nikon and GoPro. The AP's Ron Harris takes a closer look. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Buzz60 (Dec. 19, 2014) A double-amputee makes history by becoming the first person to wear and operate two prosthetic arms using only his mind. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
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