SiOnyx pulls in light with black silicon

Beverly, Mass.-based SiOnyx has pulled in its first round of funding for a technology that it says can boost the light sensitivity of semiconductors, creating what the Harvard University spinout calls black silicon.

The technology has the potential to be used cut the manufacturing and energy costs for applications in light detection, digital imaging and solar energy, as well as eliminate many of the toxic materials used to make light sensitive chips.

Founded in 2006 by Eric Mazur, professor of physics and applied physics at Harvard, and James Carey, who serves as the principal scientist for SiOnyx, the company raised $11 million in financing from Polaris Ventures, Harris & Harris and RedShift Ventures.

Today, the company said it has exclusively licensed Harvard's portfolio of black silicon patents, with the university getting an undisclosed equity position in SiOnyx under the deal, as well as future royalties.

"Black silicon is essentially a new material," Stephen Saylor, president and CEO of SiOnyx, told the Cleantech Group.

"Silicon is used in everything from the little detectors that turn the sink on in the men's room to imagers on satellites. And what the real benefit is is that our technology, black silicon, enhances the way those types of devices interact with light."

According to the company, the new material absorbs nearly twice the visible light of regular silicon and detects infrared light that is normally invisible to silicon based devices.

It's manufactured by shining a series of short, intense laser pulses at a silicon surface in air, causing the air to react with the silicon and etch away some of the surface, leaving a pattern of spikes.

Because it becomes so light absorbing, the normally gray and shiny surface turns deep black in the process.

Take a look at some black silicon here >>

The company said regular silicon absorbs a moderate amount of visible light, but the spiked silicon surface absorbs nearly all light at wavelengths ranging from the ultraviolet to the infrared.

Last year, another Harvard cleantech spinout raised some cash, with Quincy, Mass.-based fuel cell developer SiEnergy Systems pulling in $500,000 from Boston's Allied Minds, a pre-seed investment firm.

SiEnergy is working on a solid oxide fuel cell technology that provides low-temperature operation with high power density. The company is targeting power for small vehicles, such as forklifts, scooters, and recreational vehicles, as well as backup power applications and power for portable electronics.

For SiOnyx, solar applications could happen in the long term, but Saylor said the nearest opportunity will likely be in some very simple applications where the small semiconductor devices can deliver big benefits.

"And that would be areas like medical imaging, where you have the sensitivity of your detector has a direct relationship to how much radiation you may have to receive, for instance."

In a white paper, the company said the detector arrays for machines including PET and CT scanners also account for as much as 30 percent of the system cost and require in excess of 300 volts to extract sufficient signal for the measurement. SiOnyx said black silicon can operate at just 3 volts.

Black silicon could also cut down on the use of hazardous materials.

"A lot of infrared detectors are made of toxic materials that are very, very bad in a landfill," said Saylor. "Cadmium sulfide is a huge technology platform for infrared detection, so is mercury cadmium teluride, so are lead salts, indium gallium arsenide."

He said the company's black silicon detectors are completely inert and are compatible with standard semiconductor processing technology.

Companies like San Diego-based PowerGenix are also capitalizing on a move toward non-toxic materials. The company, which makes rechargeable nickel-zinc batteries, pulled in $30 million in its latest round of financing in September (see PowerGenix snags $30M for nickel-zinc batteries).

The first simple detector products using black silicon could be coming soon. "Those would get deployed in a variety of different applications," said Saylor. "Those will become available to customers next year."

As for the future for black silicon, Saylor said it could transform the $10 billion light detection, imaging and photovoltaic markets by offering smaller, lighter and more efficient systems.

"If you look at a digital camera, the sensor on a digital camera just happens to be millions of photo detectors. If you look at a solar panel, it just happens to be a very large photo detector. Now, they're optimized in different ways, but the basic physical chemistry, the basic device physics, is the same. You are capturing photons and converting them into electrical signals."