15 August 2012

Graphene’s conductivity depends on the underlying material

Researchers at MIT have shown that graphene behaves differently depending on the material it's wrapped around.

When the team placed sheets of graphene on substrates made of different materials, properties such as how the graphene conducts electricity and how it interacts chemically with other materials were found to be drastically different, depending on the nature of the underlying material.

When the material underneath was silicon dioxide, a standard material used in electronics, the graphene became 'functionalised' when exposed to certain chemicals. But when graphene sat on boron nitride, it hardly reacted to the same chemicals.

"It's very counterintuitive," commented Michael Strano, the Charles and Hilda Roddey professor of chemical engineering at MIT. "You can turn off and turn on graphene's ability to form chemical bonds, based on what's underneath."

The team found that this is because the material is so thin that how it reacts is strongly affected by the electrical fields of atoms in the material beneath it. Therefore it is possible to create devices with a micropatterned substrate covered with a layer of graphene whose chemical behaviour will then vary according to the hidden patterning. This could enable the production of microarrays of sensors to detect trace biological or chemical materials.

"You could get different molecules of a delicate biological marker to interact [with these regions on the graphene surface] without disrupting the biomolecules themselves," said MIT postdoc Qing Hua Wang. Most current fabrication techniques for such patterned surfaces involve heat and reactive solvents that can destroy these sensitive biological molecules.

The next step for the MIT team is to investigate whether bi layer graphene reacts differently to the single layer material.

The image shows a graphene layer on top of a patterned substrate and highlights the difference in chemical reactivity of the side opposite the substrate. The wide red stripe is an area over a silicon dioxide substrate, making the top surface of the graphene highly reactive. The narrow blue stripe is graphene over a layer of hydrocarbon (called OTS), and there is almost no reactivity on the side not in contact with the substrate.

Author
Simon Fogg

Supporting Information

Websites
http://web.mit.edu/

This material is protected by Findlay Media copyright
See Terms and Conditions.
One-off usage is permitted but bulk copying is not.
For multiple copies contact the sales team.

Do you have any comments about this article?


Add your comments

Name
 
Email
 
Comments
 

Your comments/feedback may be edited prior to publishing. Not all entries will be published.
Please view our Terms and Conditions before leaving a comment.

Related Articles

£2.75m for feasibility studies

The Technology Strategy Board, Invest Northern Ireland and Highlands and ...

Amp works at 50% efficiency

Researchers from the Universities of Bristol and Cardiff have created an ...

Materials breakthrough

A technique to study the interface between materials, developed at the National ...

Down to the wire

Once the plain old telephone service, the role of the telephone wire continues ...

Within touching distance

Graphene is starting to filter onto the market. HEAD claims its tennis racquets ...

Making light work of photonics

Today's world is permeated by electronics, from industry to communications, ...

NI Trend Watch 2014

This report from National Instruments summarises the latest trends in the ...

Capactive sensing

This whitepaper looks at a number of capacitive sensing applications to ...

Altium's Innovation Station

An introduction to the Altium Innovation Station. It includes an overview of ...

IBM tackles 22nm challenges

IBM has announced the semiconductor industry’s first computationally based ...

BEEAs 2013

9th October 2014, 8 Northumberland, London

Self-destructing electronics

Researchers at Iowa State University have created transient electronics that ...

MEMS switch for 'true 4G'

General Electric has created a 3GHz RF MEMS switch that can handle up to 5kW of ...

Smart fabrics developed at NPL

NPL has developed a new method to produce conductive textiles. The technique ...

Electronic charge to 800mph

Breaking the land speed record would require a very special blend of latest ...

Flash drives semi technologies

Demand for NAND flash is said to be growing at 45% per year, driven mainly by ...

Top tech trends for 2013

Bee Thakore, European technical marketing manager for element14, gives an ...

Nathan Hill, director, NGI

Research into graphene won Andre Geim and Kostya Novoselov the Nobel prize in ...

Brent Hudson, Sagentia

Sagentia's ceo tells Graham Pitcher how the consulting company is anticipating ...

Prof Donal Bradley, Imperial

Graham Pitcher talks to a researcher who was 'there at the start' of the ...