Navigation Links
Rice researchers make graphene hybrid
Date:3/1/2010

Rice University researchers have found a way to stitch graphene and hexagonal boron nitride (h-BN) into a two-dimensional quilt that offers new paths of exploration for materials scientists.

The technique has implications for application of graphene materials in microelectronics that scale well below the limitations of silicon determined by Moore's Law.

New research from the lab of Pulickel Ajayan, Rice's Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science and of chemistry, demonstrates a way to achieve fine control in the creation of such hybrid, 2-D structures.

Layers of h-BN a single atom thick have the same lattice structure as graphene, but electrically the materials are at opposite ends of the spectrum: h-BN is an insulator, whereas graphene, the single-atom-layer form of carbon, is highly conductive. The ability to assemble them into a single lattice could lead to a rich variety of 2-D structures with electric properties ranging from metallic conductor to semiconductor to insulator.

Because graphene is a conductor and h-BN is an insulator, the proportion of one to the other determines how well this new material conducts electrons. Lijie Ci and Li Song, both postdoctoral research scientists in Ajayan's lab, found that by putting down domains of h-BN and carbon via chemical vapor deposition (CVD), they were able to control the ratio of materials in the film that resulted.

Ci and Song are primary authors of a paper about the work that appeared in the online edition of Nature Materials this week.

Ajayan said the discovery is thrilling for a materials scientist.

"From a graphene perspective, it now gives us an opportunity to explore band-gap engineering in two-dimensional layered systems," he said. "The whole phase diagram of boron, carbon and nitrogen is fascinating, unexplored and offers a great playground for materials scientists.

"This is only the first instance showing that these structures can indeed be grown in 2-D like graphene," Ajayan said. "I think the whole new field will be exciting for basic physics and electro-optical applications."

Graphene has been the subject of intense study in recent years for its high conductivity and the possibility of manipulating it on scales that go well below the theoretical limits for silicon circuitry. A layer of graphene is a hexagonal lattice of carbon atoms. In bulk, it's called graphite, the stuff of pencil lead. Graphene was first isolated in 2004 by British scientists who used Scotch tape to pull single-atom layers from graphite.

"Graphene is a very hot material right now," said Song, who had teamed with Ci to investigate doping graphene with various materials to determine its semiconducting properties. Knowing that both boron and nitrogen had already been used in doping bulk graphite, they decided to try cooking it via CVD onto a copper base.

Structurally, h-BN is the same as graphene, a hexagon-shaped lattice of carbon atoms that looks like chicken wire. Ci and Song found that through CVD, graphene and h-BN merged into a single atomic sheet, with pools of h-BN breaking up the carbon matrix.

The critical factor for electronic materials is the band gap, which must be tuned in a controlled manner for applications. Graphene is a zero-gap material, but ways have been proposed to tailor this gap by patterning it into nanoscale strips and doping it with other elements.

Ci and Song took a different approach through CVD, controlling the ratio of carbon to h-BN over a large, useful range.

It remains challenging to produce single layers of the hybrid material, as most lab-grown films contain two or three layers. The researchers also cannot yet control the placement of h-BN pools in a single sheet or the rotational angles between layers but they're working on it.

In fact, having multiple layers of the hybrid at various angles creates even more possibilities, they said. "For pure graphene, this rotation will affect the electronic properties," said Ci, who moved with Ajayan's lab from Rensselaer Polytechnic Institute to Houston in 2007.

The researchers are considering producing these materials on industrial-scale wafers. Graphene sheets several inches wide have already been synthesized in other labs, Ci said. And because graphene can be lithographically patterned and cut into shapes, the new material has great potential to be fabricated into useful devices with controllable electrical properties.


'/>"/>

Contact: David Ruth
druth@rice.edu
713-348-6327
Rice University
Source:Eurekalert

Related biology news :

1. New dinosaur rears its head; U-M researchers part of team announcing find
2. Discovery in legumes could reduce fertilizer use, aid environment: Stanford researchers
3. Researchers fishing for cancer cure discover active DHA derivatives
4. Researchers determine how ATP, molecule bearing the fuel of life, is broken down in cells
5. NOAA, NASA and Old Dominion researchers measure impacts of changing climate on ocean biology
6. Researchers issue outlook for a significant New England red tide in 2010
7. French and Spanish researchers develop a natural alternative to antibiotics in animal feed
8. Pitt researchers report internal and environmental factors trigger unique brain activity in teens
9. MDC researchers link protein tether to touch perception
10. Caltech researchers presenting at AAAS Meeting
11. Researchers develop standard of care for breast cancer survivors with lymphedema
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:12/20/2016)... 2016 The rising popularity of mobility ... is stoking significant interest in keyless access systems. ... low energy (BLE), biometrics and near-field communication (NFC) ... of wireless technologies in the automotive industry. This ... access systems opens the market to specialist companies ...
(Date:12/16/2016)... Research and Markets has announced the addition ... to 2021" report to their offering. ... The biometric vehicle access system market, ... of 14.06% from 2016 to 2021. The market is estimated to ... 854.8 Million by 2021. The growth of the biometric vehicle access ...
(Date:12/15/2016)... ... has announced the addition of the "Global Military Biometrics Market 2016-2020" ... global military biometrics market to grow at a CAGR of 7.5% during ... on an in-depth market analysis with inputs from industry experts. The report ... The report also includes a discussion of the key vendors operating in ...
Breaking Biology News(10 mins):
(Date:1/19/2017)... LAKES, N.J. , Jan. 18, 2017 BD (Becton, ... technology company, announced today that it will host a live webcast ... at 1 p.m. (ET). The webcast can be ... be available for replay through Tuesday, January 31, 2017. ... About BD BD ...
(Date:1/18/2017)... 2017 Applied BioMath ( www.appliedbiomath.com ), ... research and development, today announced that Dr. ... of Applied BioMath, will present at the next ... Meeting on Thursday January 19, 2017 at the ... MA.   Dr. Burke,s talk "Quantitative Modeling and Simulation ...
(Date:1/18/2017)... ... January 18, 2017 , ... Whitehouse Labs ... Within Albany Molecular Research, Inc. (AMRI), the scientific staff dedicated to Extractables / ... planned for further growth in 2017. Extractable & Leachable evaluations have become increasingly ...
(Date:1/18/2017)... KING OF PRUSSIA, PA (PRWEB) , ... January ... ... to disrupt clinical operations again at the CHI SCOPE Summit for Clinical Ops ... and AstraZeneca in engaging panel discussions to examine vital clinical research issues such ...
Breaking Biology Technology: