Featured Research

from universities, journals, and other organizations

Functional Nanoribbons Carved Using Super-heated, Nano-sized Particles Of Iron

Date:
August 2, 2008
Source:
University of Pennsylvania
Summary:
Physicists at the University of Pennsylvania have demonstrated a new method by which graphene films can be etched along flawless, crystallographic axes using hot nanoparticles, a technique that results in precise, macroscopic length ribbons of graphene. The advance could enable atomically precise and simple construction of integrated circuits from single graphene sheets with a wide range of technological applications.

Due to its remarkable electronic properties, few layer graphene, or FLG, has emerged as a promising new material for use in post-silicon devices that incorporate the quantum effects that emerge at the nanoscale. Now, physicists at the University of Pennsylvania have demonstrated a new method by which FLG can be etched along flawless, crystallographic axes by using thermally activated nanoparticles, a technique that results in atomically precise, macroscopic length ribbons of graphene. The advance could enable atomically precise, and far simpler, construction of integrated circuits from single graphene sheets with a wide range of technological applications.

A.T. Charlie Johnson, professor in the Department of Physics and Astronomy at Penn, and his team have demonstrated this new etching process which relies on catalytic metal particles to etch the graphene along precise atomic directions.

Johnson’s team is now attempting to refine their control of the process and test Penn’s capability to fabricate devices whose properties will reflect the intrinsic quality of atomically precise graphene.

“Graphene is a great material for electronics, but it would be even better if it were possible to create devices with crystallographic edges, that is, edges where the atoms lie along single lines in the graphene plane,” Johnson said. “Standard etching techniques being used in the semiconductor industry do not allow this sort of fabrication. Instead, they produce rough edges with lots of atomic scale defects that limit the performance of the fabricated devices.”

Specifically, the Penn team investigated the construction of atomically precise graphene nanoribbons in which charge-carrying electrons are confined in a nearly two-dimensional, lateral plane and the electronic properties of the ribbon are controlled by the width and specific crystallographic orientation of the material. These structures hold enormous promise as nanoscale devices, with the advantage that graphene’s two-dimensionality lends itself to existing device architectures based on planar geometries.

Attempts with current nanofabrication standards such as lithography and plasma etching, however, have left rough edges to the nanoribbons that affect their performance. Until now, these structures have been impossible to achieve because the rough, non-crystalline edges of the graphene, resulting from current state-of-the-art nanolithography techniques, are considered the limiting factor to attaining useful performance from nanoscale graphene devices. Even atomic-scale flaws would derail electrical conductivity of any graphene transistors. Johnson’s technique, employing hot iron nanoparticles to carve out patterns in graphene sheets, appears to be the first detailed example of such precise fabrication.

To create these ribbons, researchers deposited graphene onto a silicon substrate, coated them in iron nitrate and heated them to 900 C. At that temperature, the iron forms particles with diameters of about 15 nm, spreads across the surface of the substrate and etches away trenches in the graphene sheets.

By identifying areas where two iron nanoparticles carved parallel tracks like skis in fresh snow, researchers managed to isolate nanoribbons as narrow as 15 nm and as much as a few micrometers long. The nanoparticles travel predominantly along a single direction, although why this was so is a question for another study. However, scientists also observed the existence of other paths of nanoparticles, at angles of 30 and 60, suggesting possibly that the motion of the iron nanoparticles — and hence the etching — is related to the atomic structure of graphene, a honeycomb shape employing those measurements. This natural phenomena could be used in the future to fabricate devices and circuits with those required angles.

The study was performed by Johnson, Sujit S. Datta and Samuel M. Khamis of the Department of Physics and Astronomy in the School of Arts and Sciences at Penn as well as Douglas R. Strachan of the Department of Physics and Astronomy and also the Department of Materials Science and Engineering within Penn’s School of Engineering and Applied Science.

The study was funded by

Penn’s Nano/Bio Interface Center

through the National Science Foundation, the Army Research Office and the Intelligence Community Postdoctoral Fellowship Program.


Story Source:

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


Cite This Page:

University of Pennsylvania. "Functional Nanoribbons Carved Using Super-heated, Nano-sized Particles Of Iron." ScienceDaily. ScienceDaily, 2 August 2008. <www.sciencedaily.com/releases/2008/07/080731140237.htm>.
University of Pennsylvania. (2008, August 2). Functional Nanoribbons Carved Using Super-heated, Nano-sized Particles Of Iron. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2008/07/080731140237.htm
University of Pennsylvania. "Functional Nanoribbons Carved Using Super-heated, Nano-sized Particles Of Iron." ScienceDaily. www.sciencedaily.com/releases/2008/07/080731140237.htm (accessed October 20, 2014).

Share This



More Matter & Energy News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gulfstream G500, G600 Unveiling

Gulfstream G500, G600 Unveiling

Flying (Oct. 20, 2014) Watch Gulfstream's public launch of the G500 and G600 at their headquarters in Savannah, Ga., along with a surprise unveiling of the G500, which taxied up under its own power. Video provided by Flying
Powered by NewsLook.com
Japanese Scientists Unveil Floating 3D Projection

Japanese Scientists Unveil Floating 3D Projection

Reuters - Innovations Video Online (Oct. 20, 2014) Scientists in Tokyo have demonstrated what they say is the world's first 3D projection that floats in mid air. A laser that fires a pulse up to a thousand times a second superheats molecules in the air, creating a spark which can be guided to certain points in the air to shape what the human eye perceives as an image. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
What We Know About Microsoft's Rumored Smartwatch

What We Know About Microsoft's Rumored Smartwatch

Newsy (Oct. 20, 2014) Microsoft will reportedly release a smartwatch that works across different mobile platforms, has a two-day battery life and tracks heart rate. 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