Navigation Links
Rice researchers make graphene hybrid

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
Rice University

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:
(Date:11/10/2015)... LONDON , Nov. 10, 2015 /PRNewswire/ ... segmented on the basis of product, type, ... segments included in this report are consumables, ... this report are safety biomarkers, efficacy biomarkers, ... in this report are diagnostics development, drug ...
(Date:11/9/2015)... , Nov. 9, 2015  Synaptics Inc. (NASDAQ: ... solutions, today announced broader entry into the automotive market ... that match the pace of consumer electronics human interface ... sensors are ideal for the automotive industry and will ... Europe , Japan ...
(Date:10/29/2015)... MINNETONKA, Minn. , Oct. 29, 2015   ... that supports the entire spectrum of clinical research, is ... the Minnesota High Tech Association (MHTA) as one of ... in the "Software – Small and Growing" category. The ... and individuals who have shown superior technology innovation and ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... , Nov. 24, 2015 Halozyme Therapeutics, Inc. (NASDAQ: ... in New York on Wednesday, December 2 ... Torley , president and CEO, will provide a corporate overview. ... York at 1:00 p.m. ET/10:00 a.m. PT . ... relations, will provide a corporate overview. --> th ...
(Date:11/24/2015)... Inc., a worldwide provider of clinical research services headquartered in ... has set a new quarterly earnings record in Q3 of 2015.  ... Q3 of 2014 to Q3 of 2015.   ... the establishment of an Asia-Pacific office to ... and Mexico , with the establishment ...
(Date:11/24/2015)... 24, 2015 --> ... report released by Transparency Market Research, the global non-invasive ... CAGR of 17.5% during the period between 2014 and ... Global Industry Analysis, Size, Volume, Share, Growth, Trends and ... testing market to reach a valuation of US$2.38 bn ...
(Date:11/24/2015)... ... , ... InSphero AG, the leading supplier of easy-to-use solutions for production, culture, ... serve as Chief Operating Officer. , Having joined InSphero in November 2013 ... was promoted to Head of InSphero Diagnostics in 2014. There she has built ...
Breaking Biology Technology: