Structural modification of diamond-wire-cut multicrystalline Si by Cu-catalyzed chemical etching for surface structuring

Abstract

During the multicrystalline Si (mc-Si) solar cell production, metal-catalyzed chemical etching (MCCE) is an effective method for constructing texture surface on diamond wire sawing (DWS) cut mc-Si wafer. A dense Cu film was formed on silicon surface by Cu-MCCE, significantly restricting the etching process. In this work, FeCl3, MnO2 and H2O2, were selected to modify the structure of texture surface by one-step Cu-MCCE method. A wedge-shaped structure was formed when the concentration of FeCl3 and etching time are 0.2 mol/L and 15 min, and its reflectivity is 22.9%. A composite structure with shallow pits and nanopores was formed when the amount of MnO2 and etching time are 50 g/L and 20 min, and its reflectivity is 23.2%. An inverted pyramid structure was formed when the concentration of H2O2 and etching time are 3 mol/L and 15 min, and its reflectivity is 18.2%. The best conversion efficiency (η) of solar cell obtained is 19.0%, and, the depth-to-width ratio of texture structure is 1.33.