The Hippo


Apr 17, 2014








Faster than silicon
Graphene will be in your computer someday

By John Andrews

Carbon gets a lot of flak these days. Carbon dioxide is the primary driver of global climate change, sure, but do the two oxygen atoms share any of the blame? Everyone talks about trading “carbon credits” and reducing your “carbon footprint.” Discrimination, it is.

Fact is, when carbon hangs out by itself, it can do some pretty awesome things. Like in graphene.

Graphene is “just” carbon in much the same way diamonds are “just” carbon.  There are no other elements mixed in, but the arrangement of carbon atoms gives the substance unique properties. Diamonds, in a cubic lattice structure, are extremely hard, clear and expensive. Graphene has a hexagonal lattice structure, so a sheet of the stuff is only one atom thick.

If you’re thinking the name sounds a lot like “graphite,” there’s a reason for that. When carbon appears by itself in nature, it’s usually as graphite. Meticulously separate all the layers of graphite and you’ll end up with graphene.

Graphene is also virtually transparent and electrically conductive. With such properties, it has a lot of uses in computing.

Transistors, and the memory and processors they make up, have traditionally been made of silicon. That’s one row down on the periodic table from carbon, so they share some characteristics. When arranged as graphene, carbon suddenly becomes much more useful.
How much more? How about a thousand times more?

One possible use of graphene is in memory. Apparently cobalt is a major ingredient in our current recipe for data storage, but a single “grain” of cobalt has 50,000 atoms. Attaching graphene, which can be isolated into much smaller grains, can make memory about a thousand times more dense. That’s a lot more stuff that can be stored in the same amount of physical space.

Bigger is better, but faster is fantastic … er. A year ago, IBM showed off a transistor that operated at 100GHz. You read that right, but read carefully: that’s a single transistor, so comparing it directly to the Core i7 or Phenom processor in your laptop won’t work. When you combine thousands and thousands of individual transistors into a general-purpose processor, you introduce a lot of delay as electrons travel from one to another.

Graphene’s low resistance seriously reduces that delay, though, so in addition to switching quickly by itself, a graphene transistor passes signals very fast. A processor is unlikely to be made out of just graphene, but even combined with silicon, future CPUs could hit 1THz — that’s one terahertz, or 1000GHz.

Another application of graphene could be exceptionally thin, even flexible touchscreens. Touch overlays, measuring in excess of two feet diagonally, have already been produced. Obviously that’s plenty big enough to go over existing LCD screens on phones and computers. If the display itself can be made of atomically thin sheets, and the processor and memory can be as well, what’s to stop you from rolling up your giant-screen tablet and sticking it in your pocket? Or wearing your phone as a bracelet?

But even graphene’s golden boy status isn’t assured. On Jan. 31, ran a headline reading, “ New Transistors: An Alternative to Silicon and Better Than Graphene.” Yup, it’s famous enough that there are already young punks — in this case, molybdenite — looking to knock down the up-and-coming prince.

It’ll be years before we see these new products in stores, but it’s nice to look forward to, huh?

®2014 Hippo Press. site by wedu