US Patent 8075792 - Metal nanoparticle etchant for silicon surfaces

http://www.freepatentsonline.com/8075792.html

One way to improve the efficiency of silicon solar cells is to minimize the reflectivity of silicon surfaces. This patent from the Alliance for Sustainable Energy teaches a way to use gold or silver nanoparticles in an etching solution to roughen silicon surfaces and improve the efficiency of silicon solar cells. Claim 1 reads:

1. A method of texturing a silicon surface, comprising:

positioning a substrate with a silicon surface in a vessel;

filling the vessel with a volume of an etching solution that covers the silicon surface of the substrate, wherein the etching solution comprises a catalytic nanomaterial and a oxidant-etchant solution comprising an etching agent and a silicon oxidizing agent; and

etching the silicon surface by agitating the etching solution in the vessel.