A Glimmer of Light From Silicon

Engineers get silicon nanowires to emit light, but a silicon laser remains on the horizon

3 min read
A Glimmer of Light From Silicon
Surface Plasmons Light Silicon: As great as it would be to have lasers and computer chips that are made of the same stuff, silicon is a very reluctant light emitter. But electromagnetic oscillations at the boundary of a silicon nanowire and silver—surface plasmons—can overcome this problem, engineers recently found.
Illustration by Emily Cooper

Getting silicon to emit light is no easy feat, but it remains the dream of many photonics engineers, who almost reflexively refer to it as “the holy grail.” Now a team of materials scientists at the University of Pennsylvania say they might have managed it.

“This is the first demonstration of bulk silicon emitting light in the visible range,” says Ritesh Agarwal, head of the Nanoscale Phase-Change and Photonics group at UPenn.

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

3 Ways 3D Chip Tech Is Upending Computing

AMD, Graphcore, and Intel show why the industry’s leading edge is going vertical

8 min read
A stack of 3 images.  One of a chip, another is a group of chips and a single grey chip.
Intel; Graphcore; AMD

A crop of high-performance processors is showing that the new direction for continuing Moore’s Law is all about up. Each generation of processor needs to perform better than the last, and, at its most basic, that means integrating more logic onto the silicon. But there are two problems: One is that our ability to shrink transistors and the logic and memory blocks they make up is slowing down. The other is that chips have reached their size limits. Photolithography tools can pattern only an area of about 850 square millimeters, which is about the size of a top-of-the-line Nvidia GPU.

For a few years now, developers of systems-on-chips have begun to break up their ever-larger designs into smaller chiplets and link them together inside the same package to effectively increase the silicon area, among other advantages. In CPUs, these links have mostly been so-called 2.5D, where the chiplets are set beside each other and connected using short, dense interconnects. Momentum for this type of integration will likely only grow now that most of the major manufacturers have agreed on a 2.5D chiplet-to-chiplet communications standard.

Keep Reading ↓Show less