A method to fabricate low reflectivity poly- crystalline Si (poly-Si) surface structures for solar cells has been developed by use of catalytic activity of a metal film. Immersion of Si contacted with platinum (Pt) films in hydrogen peroxide plus hydrofluoric acid solutions results in etching of Si only in the contacted areas. When the Pt surface possesses a pyramidal structure, an inverted pyramidal structure is formed on Si (111) and poly- Si surfaces on which the conventional alkaline etching method cannot form mat-textured surfaces. Poly-Si surfaces with the inverted pyramidal structure possess a reflectivity lower than that of the mattextured surfaces on the Si (100) surfaces. (c) 2010 The Electrochemical Society. [DOI: 10.1149/1.3515990] All rights reserved.