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One-atom-thick germanium sheets could replace silicon in semiconductors

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April 12, 2013

A chunk of germanium in its natural form (Photo: Gibe)

A chunk of germanium in its natural form (Photo: Gibe)

It consists of one-atom-thick sheets and it could revolutionize electronics ... but it’s not graphene. Chemists at Ohio State University, instead of creating graphene from carbon atoms, have used sheets of germanium atoms to create a substance known as germanane. Because of its numerous advantages over silicon, it could become the material of choice for semiconductors.

Germanium was used to create the first experimental microchips over 60 years ago, and Ohio State assistant professor of chemistry Joshua Goldberger wondered if it could still give graphene a run for its money. “Most people think of graphene as the electronic material of the future,” he said. “But silicon and germanium are still the materials of the present. Sixty years’ worth of brainpower has gone into developing techniques to make chips out of them. So we’ve been searching for unique forms of silicon and germanium with advantageous properties, to get the benefits of a new material but with less cost and using existing technology.”

The resulting material has been shown to conduct electrons ten times faster than silicon (and five times faster than conventional germanium), meaning that it could carry a proportionately higher load if used in microchips. It’s also more chemically stable than silicon, not oxidizing in the presence of air or water, plus it’s much better at absorbing and emitting light – this means that it could prove particularly useful in solar cells.

Scientist have created germanane before, although apparently never in sufficient quantities to conduct such an extensive study of its properties, or to allow for large-scale production. To make their germanane, Goldberger and his team took a unique approach.

Ordinarily, germanium takes the form of multilayered crystals. The single-atom-thick layers are bonded to one another, and each one is quite unstable on its own. The OSU researchers created their own germanium crystals, in which calcium atoms were inserted between the layers. That calcium was then dissolved using water, leaving empty chemical bonds in its absence. Those bonds were subsequently plugged with hydrogen, resulting in much more stable layers that could be peeled from the crystal while remaining intact.

Goldberger and his team now plan on investigating how the material’s properties could be tweaked, by changing the configuration of the atoms within a single sheet.

A paper on the research was recently published in the journal ACS Nano.

Source: Ohio State University

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
4 Comments

There's still one major advantage to silicon that germanium can never match. It's abundant and cheap, a couple of orders of magnitude cheaper than germanium, the last I knew.

Gadgeteer
12th April, 2013 @ 06:13 pm PDT

So they cannot stack this to make a memristor as can be done with graphene or is this question not germane to the topic at hand.

Mitko Ian
12th April, 2013 @ 10:12 pm PDT

Doesn't the one atom thick germanane make any supply of germanium as abundant or more abundant than silicone?

dave068
13th April, 2013 @ 10:51 am PDT

dave068,

Total reserves of germanium in the US are estimated at a few hundred tons. Refined silicon is produced by the millions of tons every year. As abundant? Hardly. And what do you think would happen to the price of germanium if demand for it increased because it's being used in billions of computers every year, while supply can't be increased? Besides, this is research on the very basic properties of germanane and its production. Even assuming it pans out as a workable technology, it'll be at least 20 years before it even comes out of the lab. It's been known for decades that gallium arsenide is superior to silicon for semiconductors, but you don't see any GaAs circuits in consumer products.

FYI, silicon is not the same as silicone.

Gadgeteer
13th April, 2013 @ 06:14 pm PDT
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