The effects of Ag particle morphology on the antireflective properties of silicon textured using Ag-assisted chemical etching

Metal assisted chemical etching (MaCE) of silicon wafers is of interest for fabrication of antireflective layers for single-crystal Si solar cells. This paper presents an Ag-assisted chemical etching approach for single-crystal Si that generates wafer scale micro-and nano-porous textures with controlled surface morphologies and reflectance properties. The approach begins with an Ag thin film annealing process to form Ag micro- and nanoparticles on the Si substrate. This is followed by MaCE, where the Ag particles serve as a catalyst to produce a micro-and nano-porous texture on the Si surface. The morphology of the fabricated Si micro-and nanopores is controlled in accordance with the size and shape of the Ag particles, which are tuned by annealing the Ag films at different temperatures from 300 to 800 degrees C. The reflectance of the Si surface is in turn determined by the morphology of the etched texture. The fabricated Si antireflective textures have compound hierarchical structures, and an average reflectance of similar to 4.7% is obtained when the Ag film is annealed at 600 degrees C. (C) 2016 Elsevier B.V. All rights reserved.