Much has been made of how graphene’s lack of an inherent band gap holds it back in electronics applications.
But there are a couple of flaws in this argument. For one, not all would-be applications require the band gap seen in silicon-based materials. And what if there is actually more than one type of graphene?
Researchers at the University of Calfornia Riverside, in collaboration with researchers from The University of Texas at Austin, The University of Texas at Dallas and Xiamen University in China have in fact developed a new form of graphene whose purpose makes its lack of a bandgap irrelevant.
The researchers, led by Aelxander Balandin, a professor of electrical engineering at UC Riverside, and Professor Rodney S. Ruoff of UT Austin, have isotopically engineered graphene so it that has concentrations of 99.99 percent 12C (carbon) as opposed to the naturally occurring graphene that is found in concentrations of 98.9 percent 12C and 1.1 percent 13C.
What difference does 1 percent make? In a paper ("Thermal conductivity of isotopically modified graphene") published in the 8 Jan online version of the journal Nature Materials, the team reported that the slight variation in graphene's composition that they were able to achieve using chemical vapor deposition yielded a material that had remarkable heat dissipation qualities. They say that the isotopically engineered graphene should should be useful in heat removal applications in a number of electronics applications as well as in photovoltaics.
“The important finding is the possibility of a strong enhancement of thermal conduction properties of isotopically pure graphene without substantial alteration of electrical, optical and other physical properties,” said Balandin in the UC Riverside press release. “Isotopically pure graphene can become an excellent choice for many practical applications provided that the cost of the material is kept under control.”
Importantly, the proposed applications do not call for graphene to replace silicon in the integrated circuit of the future, but for its use in the interconnects and thermal spreaders within computers or in transparent electrodes in photovoltaics.
Still, it's important to remember that while application proposals are intriguing at this stage, this is basic research. As Balandin remarks: “The experimental data on heat conduction in isotopically engineered graphene is also crucially important for developing an accurate theory of thermal conductivity in graphene and other two-dimensional crystals.”
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.