Modulated surface-textured substrates with high haze: From concept to application in thin-film silicon solar cells

Modulated surface-textured substrates exhibiting high haze in a broad range of wavelengths were fabricated. Glass substrates coated with different thicknesses of a sacrificial layer were wet-etched allowing the manipulation of the surface morphology with surface roughness ranging from 200 nm up to 1000 nm. Subsequently, zinc-oxide layers were sputtered and then wet-etched constituting the final modulated textures. The morphological analysis of the substrates demonstrated the modulation of surface morphology. The optical analysis revealed high haze parameters and broad angle intensity distributions, which is explained in terms of superposition of different scattering mechanisms. A small anti-reflective effect with respect to untreated glass was found for the etched glass samples. Amorphous silicon solar cells on high-haze substrates were fabricated and their performance was evaluated. The solar cells outperformed the reference cell fabricated on a randomly-textured zinc-oxide-coated flat glass. The trend in the efficiency resembled the increased surface roughness and the anti-reflective effect was confirmed also in solar cell devices.