One-atom-thick
germanium sheets could replace silicon in semiconductors
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 multi layered 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.
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