Easier Way of Making Black Silicon Discovered

[Guest_Jim_*]

In general, simplifying a process by reducing steps is a good thing for a number of reasons, such as reducing costs and improving scalability. Researchers at Rice University have recently discovered a way to remove some steps to the production of black silicon for use as solar cells. This discovery could bring the technology closer to commercialization.

Black silicon is silicon with a special textured surface with features smaller than the wavelength of light. This makes it very efficient at capturing light at any angle. The Rice researchers have been working to fine tune the creation process for a while, but were surprised to find that the electrodes were actually able to catalyze the etching process, removing the need for other catalyst particles. Normally the metal electrodes are added last, but when the researchers had applied the electrodes earlier, and then repeated the process without the catalyst, they found black silicon formed near the electrodes.

Interestingly the etching always occurred the same distance from the electrodes, which was actually a tip-off to what was happening. An electrochemical process is causing the etching and the distance away from the electrodes is determined by the conductivity of the silicon, because after a point the charge carriers cannot move any farther. Now the trick is to optimize the process further, which the researchers suggest could be by applying a thin layer of gold on top of the silicon, with titanium sandwiched between, because it bonds well to both.

Source: Rice University

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