INDUSTRY NEWS

Black magic

Professor Eric Mazur and his team of graduate students at Harvard University weren't looking to discover anything when they put a sliver of silicon in a vacuum chamber, added some halogen gas, and repeatedly zapped the silicon with rapid blasts from a laser. They thought perhaps they'd see the birth of a new molecule during what they call a typical scientific "magic moment." Five hundred femtosecond pulses later they had accidentally created a new type of material that has private industry and government agencies such as NASA burning up the phone lines to Mazur's physics lab.

The material causing the stir is called black silicon. Zeus-like, the pulses transform the shiny silicon surface into a soot-black chip that, under the electron microscope, contains a dense forest of spikes measuring tens of microns in height. The needle-like spires absorb light like a black hole gulps matter. They also absorb IR radiation. Black silicon "has absorption characteristics that are unlike anything that has ever been seen before," Mazur claims. Why it acts as it does, though, is "totally mystifying and baffling" and probably has something to do with the chemical reactions with the laser and surrounding gas.

Since revealing his group's findings, "We're getting bombarded with queries from industry about its many tantalizing practical applications," Mazur says. The patent-pending material could be used to monitor atmospheric particles, placed in solar cells, integrated into electronic displays, or used in fiber-optic telecom.