Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

What can happen when graphene meets a semiconductor

22.11.2013
UWM study shows another feature that affects electron transport in graphene

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.

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.

Other contributors on the paper include Mingxing Chen, postdoctoral researcher working with Weinert, Yaoyi Li and Ying Liu, postdoctoral researchers in the Li lab (Liu is now at the Institute for Quantum Computing in Waterloo, Canada.)

Lian Li | EurekAlert!
Further information:
http://www.uwm.edu

More articles from Materials Sciences:

nachricht Materials scientist creates fabric alternative to batteries for wearable devices
12.11.2018 | University of Massachusetts at Amherst

nachricht A new path through the looking-glass
12.11.2018 | Deutsches Elektronen-Synchrotron DESY

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

The dawn of a new era for genebanks - molecular characterisation of an entire genebank collection

13.11.2018 | Life Sciences

Fish recognize their prey by electric colors

13.11.2018 | Life Sciences

Ultrasound Connects

13.11.2018 | Awards Funding

VideoLinks
Science & Research
Overview of more VideoLinks >>>