staff, staff, March 29, 2015

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A series that covers the true revolutionaries, Game Changers explores how innovators from Big Ten universities - students, faculty and alums - are inventing or reinventing their chosen fields.

Minnesota_blackphosWhether it?s a desktop PC or a mobile device, any computer you use is powered by processors that communicate with each other. And most improvements in computing efficiency and performance are fundamentally about making those processors send and receive messages faster.

Researchers at the University of Minnesota have found a new way to potentially speed up that communication using black phosphorus, a crystalline material that?s plentiful, versatile and easy to develop.

Phosphorus is a highly reactive element that makes standard kitchen matches burn when struck. But it can also be transformed into a stable, crystalline state, which is known as black phosphorus. The Minnesota team tested that material in high-speed data communication on tiny photonic circuits.

Mo Li and Steven Koester, professors in the university?s Department of Electrical and Computer Engineering, performed experiments with graduate students Nathan Youngblood and Che Chen in the university?s Nano Center. They also received support in the form of funding from the U.S. Air Force Office of Scientific Research and the National Science Foundation.

After extensive research, they published their findings in the optics and photonics journal Nature Photonics in early March.

Minnesota_blackphos2?We were the first to demonstrate the useful factor of black phosphorus,? said Youngblood, 24, a third-year graduate student and lead author of the study. ?Black phosphorus has some interesting properties, and it is also reasonably easy to grow.?

Communication between processors today takes place via a semiconductor known as graphene, which can transmit information through wideband photo-detection. But black phosphorus can allow that communication to happen within a tighter band that promotes efficiency by eliminating non-directed dispersion of light.

The University of Minnesota team determined that thin flakes of black phosphorus can be layered upon circuits, thereby eliminating the waste of escaped light as data is transmitted from one circuit to another.

?We are able to assign the black phosphorus to a thin layer, making it two-dimensional,? Youngblood said. ?It might actually be safer to say it is ultra-thin. Eliminating the thickness means the electrons are confined to moving in one direction.?

[btn-post-package]The research team showed data speeds of up to 3 billion bits per second could be transmitted and recovered. In practical terms, that loosely translates to being able to download an HD movie of average length in less than a minute.

The discovery of black phosphorus? application as a data-transfer component is still years away from being applied to consumer products on a large scale, Youngblood said. Even so, it could make a significant impact in the near term.

?We can put the phosphorus on a computer chip, and it can work in the processor cores,? he explained. ?When those cores talk to each other to perform computer processes, this application would be able to capture the light that moves between the cores.?

By Kent McDill