Strange Bedfellows

Marriage of silicon and previously incompatible semiconductors is consummated

3 min read

SILICON IS THE STUFF OF MEMORIES and microprocessors. III-V semiconductors�compounds made of elements inhabiting the third and fifth columns of the periodic table, like gallium arsenide�are the stuff of high-frequency communications chips, LEDs, and solid-state lasers. But these two types of materials have never been able to live together on the same chip. Now, researchers in Europe have found that at the nanometer scale, they can get along just fine. The researchers grew indium-phosphide and gallium-phosphide nanowires on a silicon substrate, clearing the path for the manufacture of cheaper high-frequency chips and silicon devices embedding LEDs and lasers.

A typical chip integrating these materials might consist of a silicon substrate with a large number of vertical nanowires, says Jorden van Dam of the Kavli Institute of Nanoscience at Delft University of Technology, in the Netherlands. The nano-wires could contain p-n junctions and could be embedded in an insulating polymer layer. Then, passing a current through the nanowires would cause emission of light from close to the junctions, making the device function as a tiny LED. Such nanowires could form a pixel in a display.

Keep Reading ↓Show less

This article is for IEEE members only. Join IEEE to access our full archive.

Join the world’s largest professional organization devoted to engineering and applied sciences and get access to all of Spectrum’s articles, podcasts, and special reports. Learn more →

If you're already an IEEE member, please sign in to continue reading.

Membership includes:

  • Get unlimited access to IEEE Spectrum content
  • Follow your favorite topics to create a personalized feed of IEEE Spectrum content
  • Save Spectrum articles to read later
  • Network with other technology professionals
  • Establish a professional profile
  • Create a group to share and collaborate on projects
  • Discover IEEE events and activities
  • Join and participate in discussions

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.

Keep Reading ↓Show less