Featured Research

from universities, journals, and other organizations

Graphene: What projections and humps can be good for

Date:
April 21, 2010
Source:
Physikalisch-Technische Bundesanstalt (PTB)
Summary:
Scientists in Germany have investigated how a rough base affects the electronic properties of graphene. Their results suggest that it will soon be possible to control plasmons -- collective oscillations of electrons -- purposefully in graphene, by virtually establishing a lane composed of projections and humps.

A residual interaction with the SiC substrate causes the formation of the six-fold satellite reflex structure.
Credit: Christoph Tegenkamp, Leibniz University Hanover

At present, graphene probably is the most investigated new material system worldwide. Due to its astonishing mechanical, chemical and electronic properties, it promises manifold future applications -- for example, in microelectronics. The electrons in graphene are particularly movable and could, therefore, replace silicon which is used today as the basic material of fast computer chips.

Related Articles


In a research cooperation, scientists of Leibniz University Hanover and of the Physikalisch-Technische Bundesanstalt (PTB) have now investigated in which way a rough base affects the electronic properties of the graphene layer. Their results suggest that it will soon be possible to control plasmons, i.e. collective oscillations of electrons, purposefully in the graphene, by virtually establishing a lane composed of projections and humps for them.

The results were published in the current edition of the New Journal of Physics.

The structure of graphene itself is fascinating: It consists of exactly one single, regular layer of carbon atoms. To manufacture this incredibly thin layer absolutely neatly is a great challenge. A possible method to recipitate graphene extensively on an insulating substrate is epitaxy, i.e. the controlled growth of graphene on insulating silicon carbide. For this purpose, a silicon carbide crystal is heated in vacuum. Starting from a specific temperature, carbon atoms migrate to the surface and form a monoatomic layer on the -- still solid -- silicon carbide. An important question for later applications is, how defects and steps of the silicon carbide surface affect the electronic properties of the graphene grown on it.

Within the scope of a research cooperation between PTB and Leibniz University Hanover, the influence of defects in the graphene on the electronic properties has been investigated. During the investigations, special attention was paid to the influence of the defects on a special electronic excitation, the so-called plasmons.

By different sample preparation, first of all silicon carbide crystals with different surface roughness and, thus, with a different concentration of surface defects were investigated, on which, subsequently, graphene formed. The influence of the defects on the plasmon excitations was then investigated by means of low-energy electron diffraction (SPA-LEED) and electron loss spectroscopy (EELS).

The process revealed a strong dependence of the lifetime of plasmon on the surface quality. Defects, as they are caused on step edges and grain boundaries, strongly impede the propagation of the plasmons and drastically shorten their lifetime. Here it is remarkable that the other electronic properties of the plasmons, in particular their dispersion, remain largely unaffected.

This opens up interesting possibilities for the future technical application and use of plasmons (the so-called "plasmonics") in graphene. By selective adjustment of the surface roughness, different graphene ranges could be generated in which the plasmons are either strongly dampened or can propagate almost unobstructedly. In this way, the plasmons could be conducted along "plasmon conductors" with low surface roughness specifically from one point of a graphene chip to another.


Story Source:

The above story is based on materials provided by Physikalisch-Technische Bundesanstalt (PTB). Note: Materials may be edited for content and length.


Journal Reference:

  1. T Langer, J Baringhaus, H Pfnür, H W Schumacher, C Tegenkamp. Plasmon damping below the Landau regime: the role of defects in epitaxial graphene. New Journal of Physics, 2010; 12 (3): 033017 DOI: 10.1088/1367-2630/12/3/033017

Cite This Page:

Physikalisch-Technische Bundesanstalt (PTB). "Graphene: What projections and humps can be good for." ScienceDaily. ScienceDaily, 21 April 2010. <www.sciencedaily.com/releases/2010/04/100419102415.htm>.
Physikalisch-Technische Bundesanstalt (PTB). (2010, April 21). Graphene: What projections and humps can be good for. ScienceDaily. Retrieved November 21, 2014 from www.sciencedaily.com/releases/2010/04/100419102415.htm
Physikalisch-Technische Bundesanstalt (PTB). "Graphene: What projections and humps can be good for." ScienceDaily. www.sciencedaily.com/releases/2010/04/100419102415.htm (accessed November 21, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, November 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

AFP (Nov. 21, 2014) — Toyota presented its hydrogen fuel-cell compact car called "Mirai" to US consumers at the Los Angeles auto show. The car should go on sale in 2015 for around $60.000. It combines stored hydrogen with oxygen to generate its own power. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Google Announces Improvements To Balloon-Borne Wi-Fi Project

Google Announces Improvements To Balloon-Borne Wi-Fi Project

Newsy (Nov. 21, 2014) — In a blog post, Google said its balloons have traveled 3 million kilometers since the start of Project Loon. Video provided by Newsy
Powered by NewsLook.com
NSA Director: China Can Damage US Power Grid

NSA Director: China Can Damage US Power Grid

AP (Nov. 20, 2014) — China and "one or two" other countries are capable of mounting cyberattacks that would shut down the electric grid and other critical systems in parts of the United States, according to Adm. Michael Rogers, director of the National Security Agency and hea Video provided by AP
Powered by NewsLook.com
Latest Minivan Crash Tests Aren't Pretty

Latest Minivan Crash Tests Aren't Pretty

Newsy (Nov. 20, 2014) — Five minivans were put to the test in head-on crash simulations by the Insurance Institute for Highway Safety. 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