NOVELTY - Aqueous alkaline composition comprises: (A) at least one quaternary ammonium hydroxide; (B) at least one component comprising water soluble sulfonic acid compounds (I) and their salts, water soluble phosphonic acids compounds (II) and their salts, water soluble sulfuric acid ester compounds (III) and their salts and water soluble phosphoric acid ester compounds (IV) and (V) and their salts; and (C) a buffer system, where at least one component other than water is volatile.    USE - The aqueous alkaline composition is useful for modifying or treating the surface of the silicon substrate, preferably a silicon wafer, which is useful for manufacturing devices generating electricity upon exposure to electromagnetic radiation, where the devices include photovoltaic cells and solar cells, preferably selective emitter solar cells, passivated emitter and rear cells, metal wrap through solar cells and emitter wrap through solar cells. The buffer system is useful for stabilizing the pH of the aqueous alkaline compositions (all claimed). The aqueous alkaline composition is useful for treating the surface of silicon substrates including silicon oxides and silicon alloy materials, preferably silicon germanium alloy materials and silicon semiconductor materials.    ADVANTAGE - The aqueous alkaline composition exhibits a stable pH or only a slight decrease or increase of its pH during their bath lifetime, and economically provides the photovoltaic or solar cells at high yield with high cleaning and improved efficiency and an uniform appearance by avoiding the formation of haze and the re-contamination of the surface of the silicon substrates.    DETAILED DESCRIPTION - Aqueous alkaline composition comprises: (A) at least one quaternary ammonium hydroxide; (B) at least one component comprising water soluble sulfonic acid compounds of formula ((R1-SO3-)nX(n+)) (I) and their salts, water soluble phosphonic acid compounds of formula (R-PO32-(X(n+)3-n)) (II) and their salts, water soluble sulfuric acid ester compounds of formula ((RO-SO3-)nX(n+)) (III) and their salts, water soluble phosphoric acid ester compounds of formulae (RO-PO32+(X(n+)3-n)) (IV) and (((RO)2PO2-)nX(n+)) (V) and their salts; and (C) a buffer system, where at least one component other than water is volatile.    X = H, ammonium, alkaline metal or alkaline earth metal;    R1 = 2-5C aliphatic group containing at least one olefinically unsaturated double bond or 4-6C cycloaliphatic group containing at least one olefinically unsaturated double bond, preferably vinyl, prop-1-en-1-yl, prop-2-en-1-yl (allyl) or alpha -methylvinyl;    R = 2-5C aliphatic group containing at least one olefinically unsaturated double bond, 4-6C cycloaliphatic group containing at least one olefinically unsaturated double bond or alkylaryl, preferably vinyl, prop-1-en-1-yl, prop-2-en-1-yl(allyl), alpha -methylvinyl or benzyl (where the aryl is phenyl or naphthalene, the alkyl is methylene, ethanediyl or propanediyl and the phosphorus atom in (II) is bonded directly and the sulfur atom in (III) and the phosphorus atom in formulae (IV) and (V) are each bonded via an oxygen atom to an aliphatic carbon atom); and    n = 1 or 2.    INDEPENDENT CLAIMS are included for:    (1) treating the surface of a silicon substrate comprising (1) providing an aqueous alkaline composition comprising (A), (B1) at least one component comprising water soluble sulfonic acids compounds of formula ((R-SO3-)nX(n+)) (Ia) and their salts, and (II)-(V), (2) contacting at least one major surface of the silicon substrate with the aqueous alkaline composition for at least once in a time at a temperature sufficient to obtain a clean hydrophilic surface, and (3) removing the major surface from the contacted aqueous alkaline composition; and    (2) manufacturing devices generating electricity upon exposure to electromagnetic radiation comprising either (a) texturing the major surface of a silicon substrate with an etching composition to generate a hydrophobic surface, (b) hydrophilizing the hydrophobic surface by the above method, (c) applying at least one spray-on emitter source onto the hydrophilic surface, (d) heating the silicon substrate contacted with the emitter source to form emitters within the silicon substrate or emitters within the silicon substrate and a silicate glass on top of the surface of the silicon substrate, (e) modifying the upper layer of the silicon substrate containing the emitters or removing the silicate glass from the surface of the silicon semiconductor and then, modifying the upper layer of the silicon substrate to obtain a hydrophobic surface, (f) hydrophilizing the hydrophobic surface by the above method, (g) depositing an antireflective layer on top of the modified upper layer of the silicon substrate to obtain an intermediate, and (h) further processing the intermediate to obtain the device, where the step (b) and/or (f) is carried, or step (a) as above per se, (b1) treating the hydrophobic surface of the silicon substrate in a heated atmosphere containing at least one gaseous emitter source to form emitters within the silicon substrate or emitters within the silicon substrate and a silicate glass on top of the surface of the silicon substrate and steps (e), (g) and (h) as above per se, where a wet edge isolation step is carried out before the step (g).    R = 2-5C aliphatic group containing at least one olefinically unsaturated double bond, 4-6C cycloaliphatic group containing at least one olefinically unsaturated double bond or alkylaryl, preferably vinyl, prop-1-en-1-yl, prop-2-en-1-yl (allyl), alpha -methylvinyl or benzyl (where the sulfur atom and the phosphorus atom in (Ia) and (II) are each bonded directly and the sulfur atom in (III) and the phosphorus atom in (IV) and (V) are each bonded via an oxygen atom to an aliphatic carbon atom).