Featured Research

from universities, journals, and other organizations

Hot Electrons In Carbon: Graphite Behaves Like Semiconductor

Date:
March 13, 2009
Source:
Forschungsverbund Berlin e.V. (FVB)
Summary:
Scientists have found that graphite behaves like a semiconductor in ultrafast time scales. The results are of fundamental importance for future electronic devices based on carbon, in which high electrical fields or frequencies are processed.

Nanomaterials like carbon possess unique properties, which have led to first applications in novel electronic devices and sensors. These materials are based on ordered, atomically thin layers of carbon atoms, for example in the form of a single layer as so-called "graphene", or rolled-up in carbon nanotubes.
Credit: Image courtesy of Forschungsverbund Berlin e.V. (FVB)

Scientists have found that graphite behaves like a semiconductor in ultrafast time scales. The results are of fundamental importance for future electronic devices based on carbon, in which high electrical fields or frequencies are processed.

Related Articles


Nanomaterials like carbon possess unique properties, which have led to first applications in novel electronic devices and sensors. These materials are based on ordered, atomically thin layers of carbon atoms, for example in the form of a single layer as so-called “graphene”, or rolled-up in carbon nanotubes. The electronic properties of such structures are closely related to those of graphite, which consists of a stack of graphene sheets.

Despite intensive research in the past, the fundamental behavior of electrons in this material are not fully understood and still controversially debated.

Markus Breusing, Claus Ropers und Thomas Elsaesser, three scientists from the Max-Born-Institute in Berlin, have now investigated the behavior of electrons in thin graphite films in real time.

As they now report in Physical Review Letters,* they recorded the dynamics of electrons with an unprecedented temporal resolution of only 10 femtoseconds (one femtosecond is a millionth of a billionth of a second). Electrons were excited to high energy states with ultrashort laser pulses, and their return to equilibrium was observed. The individual steps of this process are temporally resolved, and the momentary distribution of electrons in the material is identified. Within 30 femtoseconds, electrons form a hot gas with temperatures of 2500 C, which cools down to about 200 C in only 500 femtoseconds. The energy dissipated in this process is transferred to the crystal lattice. After this process, the electrons slowly return to their initial states.

For the first time, the study shows conclusively that, on ultrashort time scales, graphite behaves like a semiconductor, such as silicon or gallium arsenide, and not like a metal.

The observed dynamics have significant consequences for electrical transport, such as currents flowing through the material at high frequencies. The results are of fundamental importance for future electronic devices based on carbon, in which high electrical fields or frequencies are processed.

*Volume 102, Issue 08, 086809/1-4, 2009


Story Source:

The above story is based on materials provided by Forschungsverbund Berlin e.V. (FVB). Note: Materials may be edited for content and length.


Cite This Page:

Forschungsverbund Berlin e.V. (FVB). "Hot Electrons In Carbon: Graphite Behaves Like Semiconductor." ScienceDaily. ScienceDaily, 13 March 2009. <www.sciencedaily.com/releases/2009/03/090304091512.htm>.
Forschungsverbund Berlin e.V. (FVB). (2009, March 13). Hot Electrons In Carbon: Graphite Behaves Like Semiconductor. ScienceDaily. Retrieved November 25, 2014 from www.sciencedaily.com/releases/2009/03/090304091512.htm
Forschungsverbund Berlin e.V. (FVB). "Hot Electrons In Carbon: Graphite Behaves Like Semiconductor." ScienceDaily. www.sciencedaily.com/releases/2009/03/090304091512.htm (accessed November 25, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Tuesday, November 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Who Will Failed Nuclear Talks Hurt Most?

Who Will Failed Nuclear Talks Hurt Most?

Reuters - Business Video Online (Nov. 25, 2014) With no immediate prospect of sanctions relief for Iran, and no solid progress in negotiations with the West over the country's nuclear programme, Ciara Lee asks why talks have still not produced results and what a resolution would mean for both parties. Video provided by Reuters
Powered by NewsLook.com
Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Reuters - Innovations Video Online (Nov. 25, 2014) A virtual flying enthusiast converts parts of a written-off Airbus aircraft into a working flight simulator in his northern Slovenian home. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Car Park Solution for Flexible Green Energy

Car Park Solution for Flexible Green Energy

Reuters - Innovations Video Online (Nov. 24, 2014) A British solar power start-up says that by covering millions of existing car park spaces around the UK with flexible solar panels, the country's power problems could be solved. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Newsy (Nov. 23, 2014) Microsoft has robotic security guards working at its Silicon Valley Campus. Video provided by Newsy
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