Layer upon layer
Waste Management Expo 2020 MAR 12&13 BIEC, Bengaluru, India

Layer upon layer

11:49 AM, 30th June 2011
Layer upon layer
When compounds of bromine or chlorine (represented in blue) are introduced into a block of graphite (shown in green), the atoms find their way into the structure in between every third sheet, thus increasing the spacing between those sheets and making it easier to split them apart.

A new method that holds promise for making two- or three-tier graphene films that could be used for new electronic devices.

CAMBRIDGE, US: Graphene, a form of pure carbon arranged in a lattice just one atom thick, has interested countless researchers with its unique strength and its electrical and thermal conductivity. But one key property it lacks - is the ability to form a band gap, needed for devices such as transistors, computer chips and solar cells.

Now, a team of MIT scientists has found a way to produce graphene in significant quantities in a two- or three-layer form. When the layers are arranged just right, these structures give graphene the much-desired band gap.

“It’s a breakthrough in graphene technology,” said Michael Strano, Charles and Hilda Roddey Associate Professor, Chemical Engineering, MIT. The new work is described in a paper published this week in the journal Nature Nanotechnology, co-authored by graduate student Chih-Jen Shih, Professor, Chemical Engineering Daniel Blankschtein, Strano and 10 other students and postdocs.

Making graphene in quantities large enough for anything but small-scale laboratory research has been a challenge. The new method, however, can be carried out at a scale that opens up the possibility of practical applications, Strano said and makes it possible to produce the precise arrangement of the layers, that yields desirable electronic properties.

“If you want a whole lot of bilayers that are A-B stacked, this is the only way to do it,” he said.

The trick takes advantage of a technique originally developed as far back as the 1950s and ’60s by MIT Institute Professor Mildred Dresselhaus. Strano and his team found that when the graphite is dissolved, it naturally comes apart where the added atoms lie, forming graphene flakes two or three layers thick. “Because this dispersion process can be very gentle, we end up with much larger flakes” than anyone has made using other methods, Strano said. “Graphene is a very fragile material, so it requires gentle processing.”

Such formations are “One of the most promising candidates for post-silicon nanoelectronics,” the authors say in their paper. The group were able to manufacture some simple transistors on the material. A similar solvent-based method for making single-layer graphene is already being used to manufacture some flat-screen television sets, and “This is definitely a big step” toward making bilayer or trilayer devices, said Strano.

The work was supported by grants from the US Office of Naval Research through a multi-university initiative that includes Harvard University and Boston University along with MIT, as well as from the Dupont/MIT Alliance, a David H Koch fellowship, and the Army Research Office through the Institute for Soldier Nanotechnologies at MIT.

(C) MIT News Office




Your Comments (Up to 2000 characters)
Please respect our community and the integrity of its participants. WOC reserves the right to moderate and approve your comment.

Related News

Brain chemistry linked to source of stress disorders

LEICESTER, UNITED KINGDOM: An innovative Medical Research Council funded study has revealed new targeted treatment opportunities for stress-related me ...

Read more
Showa Denko to increase high-purity ammonia capacity at 3 sites

TOKYO, JAPAN: Showa Denko K K (SDK) will increase its production capacity for high-purity ammonia to meet growing demand from the electronics industry ...

Read more
BASF and EMBRAPA joint venture for R&D in Brazil

Latest agreement will speed up development and introduction of new technologies and solutions for Brazilian agriculture. Initial project will bring ...

Read more
The genius of a disorderly enzyme

USC Dornsife researchers uncover how the inefficiency of activation-induced deoxycytidine deaminase is good for your immune system. LOS ANGELES, US: ...

Read more
Pemex and Mexichem form $ 556 million vinyl chloride joint venture

MEXICO CITY, MEXICO: Pemex will form a joint venture with Mexichem to produce vinyl chloride. In order to be more competitive in the domestic oil i ...

Read more
ACS’s Kenneth G Hancock 2011 student awards in Green Chemistry

The ACS Division of Environmental Chemistry presented the Kenneth G Hancock Memorial Student Awards 2011 in Green Chemistry. It was also sponsored by ...

Read more uses cookies to ensure that we give you the best experience on our website. By using this site, you agree to our Privacy Policy and our Terms of Use. X