Monday, October 13, 2008

'Black Silicon' startup SiOnyx could revolutionize solar, imaging


You gotta admit “black silicon” has to be near the top of the most fun cleantech terms of the year. The material, which reportedly is between 100 and 500 times more sensitive to light than standard silicon, has been licensed by Massachusetts-based venture-backed startup SiOnyx from Harvard University. The New York Times and Xconomy have the story (Xconomy’s is far more detailed and actually explains the tech) about the three year old startup, which is backed by $11 million from Polaris Ventures, Harris & Harris, and RedShift. Polaris investor and ethernet inventor Bob Metcalfe sits on SiOnyx’s board.

The black silicon technique works like this: shine a very powerful pulse of a laser on a piece of silicon in the presence of the gas sulfur hexafluoride and the result is a piece of silicon marked with tiny cones. Xconomy digs even deeper into the process and explains: “the laser pulses force unusually large numbers of dopant atoms into a thin layer of silicon on the surface of the cones,” and the new structure requires less energy “to knock electrons into the conduction band.” The result is the treated silicon can absorb twice as much visible light as regular silicon and unlike standard silicon is sensitive to invisible infrared light.

The bizarre (randomly found) process can lead to amazing results, and could potentially disrupt any industry that depends on the light sensitivity of silicon. That includes the solar industry, and imaging products like night vision, medical imaging and digital cameras. Solar cells could be made that are more sensitive to light and more efficient at producing electricity, though both stories clearly state that the solar application is far in the future. Much closer is an application in medical imaging, like using less powerful more efficient Xrays, and Metcalfe tells Xconomy that the startup has already negotiated a partnership with a company active in medical imaging.

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