Here's another use for graphene—wrap transistor wires with it and boost computer chip speeds.
Scientists have discovered that replacing tantalum nitride, the existing wire sheathing material between transistors, with graphene allows chips to exchange data faster.
It's yet another use for this super-material. I've written about graphene before in a post titled "Materials breakthrough promises smaller chips."
Thin graphite material
If you're unfamiliar with this breakthrough material, graphene is the world's most conductive substance. It's better than copper.
The substance itself is a one-atom-thick sheet of graphite material. It's made headlines as a super material.
Not only is it an ultra conductor, but it's also incredibly strong and hard, and is cheap to make.
Recently discovered properties of graphene include the fact that it's photovoltaic—it drives an electrical current when exposed to light.
Plus, it can be magnetized under certain conditions, and frying it in hot solvent might create efficient batteries, some scientists think.
But you can now add super-charging microprocessors to the list, too.
Engineers at Stanford University have been experimenting with the substance and claim to have demonstrated that graphene can help electrons speed through the tiny copper wires in chips more quickly.
They've done it by replacing the existing sheath with ones made out of graphene. Chips use sheaths to protect the copper conductors, just like any other wire.
Now, you may be asking: Just how can the insulating part of a wire allow the electrons to travel faster? It's an insulator, right? Surely it doesn't have anything to do with the conductivity.
Well, the answer is that the protective sheath in this case has a dual-function, says Ling Li, one of the graduate students interviewed on the university's news website.
On the one hand the sheath isolates the copper from the silicon, which makes up the chip, but it also conducts electricity.
Normally, the transistors process data by switching. Then the copper wires between the transistors transport the data after it's been processed; and finally the isolating material acts as a barrier to stop the copper from "migrating" into the silicon transistors and preventing them from working, Li says.
Graphene's lattice-like structure, however, lets the electrons jump from one carbon atom to another, but also contains the copper atoms within the copper wire—the transistors therefore still work.
It acts as an "auxiliary conductor" allowing the "wire technology to carry more data between transistors, speeding overall chip performance in the process."
Graphene's advantage is partly that it lets the components become smaller—graphene is thinner than the incumbent tantalum nitride.
So the smaller the parts, the more you can have in the same space, and consequently the more benefit you gain.
But it also has this isolating conductivity advantage.
The Stanford scientists estimate that using the current generation of transistors and this new wire can obtain speed gains of 4% to 17%. But as transistors become smaller, gains could rise to 30%.
Ironically, the one thing graphene isn't good for is being used as a material for transistors—it doesn't switch well. This has disappointed scientists. Getting it to work right in transistors has been the one major failing of this super-conductor, and many have been resigned to not seeing graphene in transistors.
However, if these Stanford scientist are right, we may be about to see it connecting the transistors instead.
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