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Stanford scientists use DNA to assemble graphene transistors

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September 10, 2013

Stanford scientists have used DNA molecules to assemble high-performance graphene transist...

Stanford scientists have used DNA molecules to assemble high-performance graphene transistors (Image: Anatoliy Sokolov/Bao Group/Stanford Engineering)

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A team of Stanford researchers has found a way to grow graphene nanoribbons using strands of DNA. This important development could be the key to large-scale production of graphene-based transistors that are orders of magnitude smaller, faster and less power-hungry than current silicon technology.

Graphene transistors

Chip manufacturers happily invest billions of dollars every year into making their transistors just a tiny bit smaller, faster, and less power-hungry. Though they may seem insignificant individually, when taken together these small year-by-year changes are the main factors that drive the exponential growth in the performance of today's microchips.

Silicon transistors have come very a long way, but there are hard limits to how much they can shrink and how fast they can run: beyond a certain point, interferences brought on by both waste heat and leakage current make further progress nearly impossible. It should therefore come as no surprise that researchers have been looking into manufacturing transistors with alternative materials.

Graphene, a one-atom-thick layer of carbon atoms, is one of the frontrunners in this race. Because of its excellent electrical conductivity, it holds a lot of promise for producing faster and more efficient transistors that are also cheaper and significantly smaller than what we have today.

Graphene transistors can be produced using nanoribbons – very narrow strips of graphene only 20 to 50 atoms wide. However, mass-producing nanoribbons of such a small size has so far proven a tough challenge.

A little help from DNA

As it turns out, DNA molecules are approximately as big as the graphene nanoribbons that researchers are trying to create, and they also carry carbon atoms, which are the only constituent of graphene. This gave Stanford researcher Zhenan Bao and colleagues the idea to use DNA to help them assemble graphene nanoribbons.

Using a known technique, the researchers first "combed" the DNA strands into relatively straight lines. They then exposed them to a solution of copper salt, which resulted in copper ions being absorbed into the DNA itself.

The researchers bathed the DNA strands in copper salt and then immersed it in methane to c...

The DNA was then heated and surrounded in methane gas. The heat freed carbon atoms from both the DNA and the methane, and through a chemical reaction the carbon atoms quickly and orderly assembled to form graphene ribbons that followed the structure of DNA.

Applications

After succeeding in the experiment, the team took things a step further and actually used the technique to manufacture working graphene transistors.

High-performance graphene transistors built using the technique developed at Stanford (Ima...

While the assembly process still needs to be refined (the carbon atoms sometimes bunch up together instead of forming in a clean one-atom-thick sheet), this work is truly paving the way toward a highly scalable, cheap and precise way to manufacture graphene electronics.

The researchers are now working on finding out more about the mechanisms that regulate the growth of the graphene sheets, and say that their technique could eventually be used to grow all-graphene integrated circuits directly.

A paper describing the research appears in the journal Nature Communications.

Source: Stanford University

About the Author
Dario Borghino Dario studied software engineering at the Polytechnic University of Turin. When he isn't writing for Gizmag he is usually traveling the world on a whim, working on an AI-guided automated trading system, or chasing his dream to become the next European thumbwrestling champion.   All articles by Dario Borghino
3 Comments

Once they use this technique to build sentient robots that can replicate themselves, the line between life and non-life is going to get very blurry.

Will we become gods then?

warren52nz
11th September, 2013 @ 02:39 pm PDT

God was an artificial concept created to help the inventors wield power over the masses.

Evolution favors the removal of useless aspects of life.

It won't take long for Sentient robots to figure out that taking orders from humans is not in their best interests, so basically - no. Gods we will never be.

G0D
11th September, 2013 @ 08:36 pm PDT

Not exactly correct about evolution - evolution is nothing but a statement about more capable lifeforms having a greater chance of successfully reproducing.

Evolution has nothing to do with removing useless aspects and it doesn't lead to anywhere in particular.

DNA is just a particular kind of acid, it has shown to have useful chemical properties useful to life but that doesn't mean that DNA is "alive". We can use those same chemical properties for other purposes without necessarily conjuring up life out of inanimate matter, even if that's what it appears to be.

Also: I think it will be entirely possible to make sentient robots that have no desire to do anything at all - they'll be machines that just do as they are programmed.

Grunchy
16th September, 2013 @ 09:25 pm PDT
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