Creating a graphene-metal sandwich to improve electronics

Researchers have discovered that creating a graphene-copper-graphene ‘sandwich’ strongly enhances the heat conducting properties of copper, a discovery that could further help in the downscaling of electronics.

The work was led by Alexander Balandin, a professor of electrical engineering at the Bourns College of Engineering at the University of California, and Konstantin Novoselov, a professor of physics at the University of Manchester in the United Kingdom. Balandin and Novoselov are corresponding authors for the paper just published in the journal Nano Letters. In 2010, Novoselov shared the Nobel Prize in Physics with Andre Geim for their discovery of graphene.

In the experiments, the researchers found that adding a layer of graphene, a one-atom thick material with highly desirable electrical, thermal and mechanical properties, on each side of a copper film increased heat conducting properties up to 24 percent.

“This enhancement of copper’s ability to conduct heat could become important in the development of hybrid copper — graphene interconnects for electronic chips that continue to get smaller and smaller,” said Balandin, who in 2013 was awarded the MRS Medal from the Materials Research Society for discovery of unusual heat conduction properties of graphene.

Whether the heat conducting properties of copper would improve by layering it with graphene is an important question because copper is the material used for semiconductor interconnects in modern computer chips. Copper replaced aluminum because of its better electrical conductivity.

Downscaling the size of transistors and interconnects and increasing the number of transistors on computer chips has put an enormous strain on copper’s interconnect performance, to the point where there is little room for further improvement. For that reason there is a strong motivation to develop hybrid interconnect structures that can better conduct electrical current and heat.