Abstract: An aqueous acidic solution and an aqueous acidic etching solution suitable for texturizing the surface of single crystal and polycrystal silicon substrates, hydrofluoric acid; nitric acid; and at least one anionic polyether, which is surface active; a method for texturizing the surface of single crystal and polycrystal silicon substrates comprising the step of (1) contacting at least one major surface of a substrate with the said aqueous acidic etching solution; (2) etching the at least one major surface of the substrate for a time and at a temperature sufficient to obtain a surface texturization consisting of recesses and protrusions; and (3) removing the at least one major surface of the substrate from the contact with the aqueous acidic etching solution; and a method for manufacturing photovoltaic cells and solar cells using the said solution and the said texturizing method.

Abstract: An aqueous alkaline etching and cleaning composition for treating the surface of silicon substrates, the said composition comprising: (A) a quaternary ammonium hydroxide; and (B) a component selected from the group consisting of water-soluble acids and their water-soluble salts of the general formulas (I) to (V): (R1—S03-)nXn+ (I), R—P032?(Xn+)3-n (II); (RO—S03-)nXn+ (III), RO—P032?(Xn+)3-n, (IV), and [(RO)2P02-]nXn+ (V); wherein the n=1 or 2; X is hydrogen or alkaline or alkaline-earth metal; the variable R1 is an olefinically unsaturated aliphatic or cycloaliphatic moiety and R is R1 or an alkylaryl moiety; the use of the composition for treating silicon substrates, a method for treating the surface of silicon substrates, and methods for manufacturing devices generating electricity upon the exposure to electromagnetic radiation.

Abstract: An aqueous acidic etching solution suitable for texturing the surface of single crystal and polycrystal silicon substrates and containing, based on the complete weight of the solution, 3 to 10% by weight of hydrofluoric acid; 10 to 35% by weight of nitric acid; 5 to 40% by weight of sulfuric acid; and 55 to 82% by weight of water; a method for texturing the surface of single crystal and polycrystal silicon substrates comprising the step of (1) contacting at least one major surface of a substrate with the said aqueous acidic etching solution; (2) etching the at least one major surface of the substrate for a time and at a temperature sufficient to obtain a surface texture consisting of recesses and protrusions; and (3) removing the at least one major surface of the substrate from the contact with the aqueous acidic etching solution; and a method for manufacturing photovoltaic cells and solar cells using the said solution and the said texturing method.