Scientists are continually looking to push the boundaries of silicon for many reasons. Silicon is used in the construction of most all the electronic devices we take for granted each day from our computers to our mobile phones and digital cameras.

In the late 1990's, a group of researchers at Harvard developed a new type of silicon called black silicon that was created by shining a very powerful laser on a silicon wafer with sulfur hexafluoride applied to it. The new material was found to have a much greater sensitivity to light than traditional silicon making it particularly interesting for applications like solar cells.

The problem with moving black silicon from the laboratory to the foundry was that the cones created during the construction process of the black silicon created some problems in manufacturing. Wafers of black silicon are harder to mass-produce than normal silicon wafers because the cones on the surface of the wafer can break off.

The researchers studied black silicon in more detail and discovered that the creation process could be further controlled to prevent the formation of cones without destroying the much greater light absorption properties of black silicon.

The new silicon material is called pink silicon because it has a slight coloring, though it is hardly able to be distinguished from normal silicon wafers. The pink silicon wafer is completely flat and has none of the mass production issues associated with the breaking of cones discovered in black silicon.

The creation process of black silicon had two things going on according to researchers -- ablation and rapid melting combined with resolidification. The rapid melting and resolidification is the step that allows doped sulfur atoms to be trapped inside the structure of the silicon.

Researcher Mark Winkler said, "Once we posed the question, it was pretty straightforward to test it. It just took changing the way we thought, from taking it as a given that we make spikes to asking how much control we have over the material that we're making."

To create the pink silicon, the researchers simply tuned the laser to a power level that didn't cause ablation, but still allowed the rapid melting and resolidification of the silicon wafer surface. The new pink silicon allows the researchers to take measurements that were impossible to perform on black silicon allowing them to get a profile of the material below the surface of the wafer. The big question that the researchers are trying to answer is why black silicon absorbs infrared light in the first place. Pink silicon still absorbs light in the same spectrums as black silicon, but should be easier to mass-produce.

Richard Meyers from Radiation Monitoring Devices who works with black silicon said, "It comes down to low cost and existing processing technology. The silicon electronics infrastructure is cheap and in place."