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Nanoparticle-based etching of silicon surfaces

United States Patent

December 13, 2011
View the Complete Patent at the US Patent & Trademark Office
National Renewable Energy Laboratory - Visit the NREL Technology Transfer Website
A method (300) of texturing silicon surfaces (116) such to reduce reflectivity of a silicon wafer (110) for use in solar cells. The method (300) includes filling (330, 340) a vessel (122) with a volume of an etching solution (124) so as to cover the silicon surface 116) of a wafer or substrate (112). The etching solution (124) is made up of a catalytic nanomaterial (140) and an oxidant-etchant solution (146). The catalytic nanomaterial (140) may include gold or silver nanoparticles or noble metal nanoparticles, each of which may be a colloidal solution. The oxidant-etchant solution (146) includes an etching agent (142), such as hydrofluoric acid, and an oxidizing agent (144), such as hydrogen peroxide. Etching (350) is performed for a period of time including agitating or stirring the etching solution (124). The etch time may be selected such that the etched silicon surface (116) has a reflectivity of less than about 15 percent such as 1 to 10 percent in a 350 to 1000 nanometer wavelength range.
Branz; Howard (Boulder, CO), Duda; Anna (Denver, CO), Ginley; David S. (Evergreen, CO), Yost; Vernon (Littleton, CO), Meier; Daniel (Atlanta, GA), Ward; James S. (Golden, CO)
Alliance for Sustainable Energy, LLC (Golden, CO)
12/ 053,372
March 21, 2008
CONTRACTUAL ORIGIN The United States Government has rights in this invention under Contract No. DE-AC36-99GO10337 between the United States Department of Energy and the National Renewable Energy Laboratory, a Division of the Midwest Research Institute.