Graphene, Graphene, Graphene. Read all about it.

An exclusive interview with Paul Sheehan of the Office of Naval Research reveals the amazing properties of graphene and downplays its potential to replace silicon as the material of choice for electronics.
Written by Boonsri Dickinson, Contributing Editor

Graphene could one day replace silicon and improve electronics, displays, and automobiles.

There are so many research papers coming about about graphene, even the experts have a hard time keeping up. Its electronic and optical properties, chemical, thermal, and mechanical properties have garnered serious attention from academics and industry professionals alike.

After British researchers discovered graphene in 2004, and since then, other researchers have made nanometer sized transistors. Manipulating the properties of this material proved to be popular in the lab, but no one can really mass produce it

Paul Sheehan, head of nanoscience and sensors section at the Office of Naval Research, might be able to change that.

Sheehan has been using a heated tip of an atomic force microscope to change the electronic properties of graphene from insulating to a conducting material — so it can be used to one day make circuits. So far, the technique works on different forms of graphene.

If Sheehan manipulates graphene as he wishes, it's not far-fetched to think circuits could be programmed so each wafer could be custom-made. Any changes to the process could be easily programmed in the factory to suit particular needs.

What's the buzz about?

People have known since the 70's about monolayer graphite. There was no way to test its electronic properties.

This changed in 2004, when researchers discovered how to isolate graphene on an insulator.

This allowed us to test its conductive properties. You can't test a single layer of graphene when it's on metal. You have to be able to test electronic properties so you can make things.

Many people have different interests in graphene. Some want to exploit the mechanical properties, but most are interested in the electronic properties. One of the main interests is to generate graphene nanoribbons. Semiconductors have band gaps. So if you slice up graphene into ribbons, it has band gaps.

What are you working on?

Our immediate focus is figuring out how to pattern it. We've done it in a way to generate a whole wafer at a time. The benefit is a one step process.

We use these heated tips as nanoscale soldering irons. Our other effort is to make the tips indestructible. Recently, we've been coating it with diamond.

So will graphene replace silicon?

Graphene has the potential to do it, but it is a ways out.

Why focus on graphene?

You can change its properties just by changing its shape. If you make it into a nanoribbon, you can give it a band gap. If you make it into a bow tie, it becomes magnetic. You can generate a flip-flop circuit by changing the shape of the graphene.

So it's like playing with Legos.

It's strong and easy to make. The chemistry allows you to make many things with it.

This is the first few years of playing with the material. Everyone is excited about the material again. The outpouring of research on graphene is unprecedented.

Anyone can make it pretty quickly and people have made it different ways. It's not expensive to make graphene. You need an oven, a tube, argon, hydrogen, and something that is carbon rich.

How could graphene change electronics?

It will let us directly write circuitry. Right now, you have an expensive fabrication process with lots of expensive machinery. If you could directly write it, you simplify the process. Everything would be custom-made, allowing us to generate circuits on demand.

Credit: University of Illinois at Urbana-Champaign


This post was originally published on Smartplanet.com

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