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Strain Speeds Organic Transistors

Big boost in charge-carrier mobility could open organic semiconductors to new applications

4 min read
optical microscopy image of an organic semiconductor

Quicker Crystals: An optical microscopy image of an organic semiconductor shows that shearing at different speeds caused different crystalline texture and degrees of strain in the film. Just the right amount of strain made charge move a lot faster through the film.

Gaurav Giri/Stanford University
Materials scientists have found a way to double or even quadruple the speed with which charge moves through organic semiconductors, potentially opening a path toward cheap, plastic 3-D TVs.

Organic semiconductors have been intensely studied because they can be printed onto flexible plastic to produce large areas of cheap, durable circuits. But these circuits have been limited because charge moves through them at a snail's pace compared to the way it speeds through silicon.

The new technique, invented in the laboratory of Zhenan Bao at Stanford University, could lead to organic circuits that operate at frequencies up to four times as high as the best of today's organic devices. That's still barely one-hundredth the speed through crystalline silicon, but it would mean cheap printed organics could more easily substitute for amorphous silicon in displays and other gadgets.

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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.


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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