Super material tipped to succeed silicon

 

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By Stewart Mitchell

Posted on 31 Jan 2011 at 09:08

The successor to silicon in computer chips may not be the much-trumpeted graphene, but another material developed by European researchers.

According to physicists at the Ecole Polytechnique Fédérale de Lausanne, molybdenite consumes up to 100,000 times less energy than silicon and could be easier to work with than graphene.

Molybdenite, the researchers said, is abundant in nature and is currently used in steel alloys and in lubricants, but it has not previously been studied for use in electronics.

"It's a two-dimensional material, very thin and easy to use in nanotechnology. It has real potential in the fabrication of very small transistors, light-emitting diodes (LEDs) and solar cells," said EPFL Professor Andras Kis, adding that molybdenite (MoS2) is far more compact than silicon, while still allowing electrons to circulate freely.

"In a 0.65-nanometer-thick sheet of MoS2, the electrons can move around as easily as in a two-nanometer-thick sheet of silicon," he said. "But it's not currently possible to fabricate a sheet of silicon as thin as a monolayer sheet of MoS2."

According to the research, conductors using molybdenite would consume 100,000 less electricity than silicon in stand-by mode.

"Better than graphene"

Kis said molybdenite had physical advantages over graphene, which was discovered in Manchester in 2004 and has been recognised as having huge potential for computing and electronics.

The molybdenite scientists said the material's physical properties would make it easier for manufacturers to assemble stable chips.

“In solid-state physics, band theory is a way of representing the energy of electrons in a given material and in semi-conductors, electron-free spaces exist between these bands, the so-called "band gaps", the researchers said. “If the gap is not too small or too large, certain electrons can hop across the gap."

“The existence of this gap in molybdenite also gives it an advantage over graphene," the researchers said. "Considered today by many scientists as the electronics material of the future, the 'semi-metal' graphene doesn't have a gap, and it is very difficult to artificially reproduce one in the material.”