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Graphene’s New Rival

Molybdenum disulfide helps graphene transistors work better—and it makes good nanocircuits on its own, too

3 min read

Graphene has become the darling of the postsilicon crowd in the eight years since Andre Geim and Konstantin Novoselov isolated it by ripping Scotch tape off a chunk of graphite. But there are other two-dimensional nanowonders. Molybdenum disulfide (MoS2), which can be pulled off a block of molybdenite through the same process, could offer new approaches to making high-speed logic circuits—on its own or in combination with graphene.


“We spent the last seven, eight years looking at how to make transistors out of graphene,” Geim says. “But there was an elephant in the room—that you can’t really switch off current in graphene.”


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Two Startups Are Bringing Fiber to the Processor

Avicena’s blue microLEDs are the dark horse in a race with Ayar Labs’ laser-based system

5 min read
Diffuse blue light shines from a patterned surface through a ring. A blue cable leads away from it.

Avicena’s microLED chiplets could one day link all the CPUs in a computer cluster together.

Avicena

If a CPU in Seoul sends a byte of data to a processor in Prague, the information covers most of the distance as light, zipping along with no resistance. But put both those processors on the same motherboard, and they’ll need to communicate over energy-sapping copper, which slow the communication speeds possible within computers. Two Silicon Valley startups, Avicena and Ayar Labs, are doing something about that longstanding limit. If they succeed in their attempts to finally bring optical fiber all the way to the processor, it might not just accelerate computing—it might also remake it.

Both companies are developing fiber-connected chiplets, small chips meant to share a high-bandwidth connection with CPUs and other data-hungry silicon in a shared package. They are each ramping up production in 2023, though it may be a couple of years before we see a computer on the market with either product.

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